1072 lines
27 KiB
C
1072 lines
27 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* LTC2688 16 channel, 16 bit Voltage Output SoftSpan DAC driver
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*
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* Copyright 2022 Analog Devices Inc.
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*/
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#include <linux/bitfield.h>
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#include <linux/bits.h>
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#include <linux/clk.h>
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#include <linux/device.h>
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#include <linux/gpio/consumer.h>
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#include <linux/iio/iio.h>
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#include <linux/limits.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/property.h>
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#include <linux/regmap.h>
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#include <linux/regulator/consumer.h>
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#include <linux/spi/spi.h>
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#define LTC2688_DAC_CHANNELS 16
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#define LTC2688_CMD_CH_CODE(x) (0x00 + (x))
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#define LTC2688_CMD_CH_SETTING(x) (0x10 + (x))
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#define LTC2688_CMD_CH_OFFSET(x) (0X20 + (x))
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#define LTC2688_CMD_CH_GAIN(x) (0x30 + (x))
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#define LTC2688_CMD_CH_CODE_UPDATE(x) (0x40 + (x))
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#define LTC2688_CMD_CONFIG 0x70
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#define LTC2688_CMD_POWERDOWN 0x71
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#define LTC2688_CMD_A_B_SELECT 0x72
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#define LTC2688_CMD_SW_TOGGLE 0x73
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#define LTC2688_CMD_TOGGLE_DITHER_EN 0x74
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#define LTC2688_CMD_THERMAL_STAT 0x77
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#define LTC2688_CMD_UPDATE_ALL 0x7C
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#define LTC2688_CMD_NOOP 0xFF
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#define LTC2688_READ_OPERATION 0x80
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/* Channel Settings */
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#define LTC2688_CH_SPAN_MSK GENMASK(2, 0)
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#define LTC2688_CH_OVERRANGE_MSK BIT(3)
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#define LTC2688_CH_TD_SEL_MSK GENMASK(5, 4)
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#define LTC2688_CH_TGP_MAX 3
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#define LTC2688_CH_DIT_PER_MSK GENMASK(8, 6)
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#define LTC2688_CH_DIT_PH_MSK GENMASK(10, 9)
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#define LTC2688_CH_MODE_MSK BIT(11)
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#define LTC2688_DITHER_RAW_MASK GENMASK(15, 2)
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#define LTC2688_CH_CALIBBIAS_MASK GENMASK(15, 2)
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#define LTC2688_DITHER_RAW_MAX_VAL (BIT(14) - 1)
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#define LTC2688_CH_CALIBBIAS_MAX_VAL (BIT(14) - 1)
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/* Configuration register */
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#define LTC2688_CONFIG_RST BIT(15)
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#define LTC2688_CONFIG_EXT_REF BIT(1)
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#define LTC2688_DITHER_FREQ_AVAIL_N 5
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enum {
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LTC2688_SPAN_RANGE_0V_5V,
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LTC2688_SPAN_RANGE_0V_10V,
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LTC2688_SPAN_RANGE_M5V_5V,
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LTC2688_SPAN_RANGE_M10V_10V,
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LTC2688_SPAN_RANGE_M15V_15V,
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LTC2688_SPAN_RANGE_MAX
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};
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enum {
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LTC2688_MODE_DEFAULT,
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LTC2688_MODE_DITHER_TOGGLE,
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};
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struct ltc2688_chan {
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long dither_frequency[LTC2688_DITHER_FREQ_AVAIL_N];
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bool overrange;
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bool toggle_chan;
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u8 mode;
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};
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struct ltc2688_state {
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struct spi_device *spi;
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struct regmap *regmap;
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struct regulator_bulk_data regulators[2];
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struct ltc2688_chan channels[LTC2688_DAC_CHANNELS];
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struct iio_chan_spec *iio_chan;
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/* lock to protect against multiple access to the device and shared data */
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struct mutex lock;
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int vref;
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/*
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* DMA (thus cache coherency maintenance) requires the
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* transfer buffers to live in their own cache lines.
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*/
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u8 tx_data[6] ____cacheline_aligned;
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u8 rx_data[3];
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};
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static int ltc2688_spi_read(void *context, const void *reg, size_t reg_size,
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void *val, size_t val_size)
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{
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struct ltc2688_state *st = context;
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struct spi_transfer xfers[] = {
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{
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.tx_buf = st->tx_data,
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.bits_per_word = 8,
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.len = reg_size + val_size,
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.cs_change = 1,
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}, {
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.tx_buf = st->tx_data + 3,
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.rx_buf = st->rx_data,
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.bits_per_word = 8,
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.len = reg_size + val_size,
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},
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};
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int ret;
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memcpy(st->tx_data, reg, reg_size);
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ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
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if (ret)
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return ret;
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memcpy(val, &st->rx_data[1], val_size);
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return 0;
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}
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static int ltc2688_spi_write(void *context, const void *data, size_t count)
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{
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struct ltc2688_state *st = context;
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return spi_write(st->spi, data, count);
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}
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static int ltc2688_span_get(const struct ltc2688_state *st, int c)
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{
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int ret, reg, span;
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ret = regmap_read(st->regmap, LTC2688_CMD_CH_SETTING(c), ®);
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if (ret)
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return ret;
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span = FIELD_GET(LTC2688_CH_SPAN_MSK, reg);
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/* sanity check to make sure we don't get any weird value from the HW */
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if (span >= LTC2688_SPAN_RANGE_MAX)
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return -EIO;
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return span;
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}
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static const int ltc2688_span_helper[LTC2688_SPAN_RANGE_MAX][2] = {
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{0, 5000}, {0, 10000}, {-5000, 5000}, {-10000, 10000}, {-15000, 15000},
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};
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static int ltc2688_scale_get(const struct ltc2688_state *st, int c, int *val)
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{
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const struct ltc2688_chan *chan = &st->channels[c];
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int span, fs;
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span = ltc2688_span_get(st, c);
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if (span < 0)
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return span;
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fs = ltc2688_span_helper[span][1] - ltc2688_span_helper[span][0];
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if (chan->overrange)
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fs = mult_frac(fs, 105, 100);
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*val = DIV_ROUND_CLOSEST(fs * st->vref, 4096);
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return 0;
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}
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static int ltc2688_offset_get(const struct ltc2688_state *st, int c, int *val)
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{
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int span;
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span = ltc2688_span_get(st, c);
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if (span < 0)
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return span;
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if (ltc2688_span_helper[span][0] < 0)
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*val = -32768;
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else
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*val = 0;
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return 0;
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}
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enum {
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LTC2688_INPUT_A,
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LTC2688_INPUT_B,
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LTC2688_INPUT_B_AVAIL,
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LTC2688_DITHER_OFF,
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LTC2688_DITHER_FREQ_AVAIL,
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};
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static int ltc2688_dac_code_write(struct ltc2688_state *st, u32 chan, u32 input,
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u16 code)
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{
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struct ltc2688_chan *c = &st->channels[chan];
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int ret, reg;
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/* 2 LSBs set to 0 if writing dither amplitude */
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if (!c->toggle_chan && input == LTC2688_INPUT_B) {
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if (code > LTC2688_DITHER_RAW_MAX_VAL)
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return -EINVAL;
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code = FIELD_PREP(LTC2688_DITHER_RAW_MASK, code);
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}
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mutex_lock(&st->lock);
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/* select the correct input register to read from */
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ret = regmap_update_bits(st->regmap, LTC2688_CMD_A_B_SELECT, BIT(chan),
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input << chan);
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if (ret)
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goto out_unlock;
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/*
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* If in dither/toggle mode the dac should be updated by an
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* external signal (or sw toggle) and not here.
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*/
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if (c->mode == LTC2688_MODE_DEFAULT)
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reg = LTC2688_CMD_CH_CODE_UPDATE(chan);
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else
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reg = LTC2688_CMD_CH_CODE(chan);
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ret = regmap_write(st->regmap, reg, code);
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out_unlock:
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mutex_unlock(&st->lock);
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return ret;
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}
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static int ltc2688_dac_code_read(struct ltc2688_state *st, u32 chan, u32 input,
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u32 *code)
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{
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struct ltc2688_chan *c = &st->channels[chan];
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int ret;
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mutex_lock(&st->lock);
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ret = regmap_update_bits(st->regmap, LTC2688_CMD_A_B_SELECT, BIT(chan),
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input << chan);
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if (ret)
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goto out_unlock;
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ret = regmap_read(st->regmap, LTC2688_CMD_CH_CODE(chan), code);
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out_unlock:
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mutex_unlock(&st->lock);
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if (!c->toggle_chan && input == LTC2688_INPUT_B)
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*code = FIELD_GET(LTC2688_DITHER_RAW_MASK, *code);
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return ret;
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}
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static const int ltc2688_raw_range[] = {0, 1, U16_MAX};
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static int ltc2688_read_avail(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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const int **vals, int *type, int *length,
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long info)
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{
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switch (info) {
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case IIO_CHAN_INFO_RAW:
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*vals = ltc2688_raw_range;
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*type = IIO_VAL_INT;
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return IIO_AVAIL_RANGE;
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default:
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return -EINVAL;
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}
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}
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static int ltc2688_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int *val,
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int *val2, long info)
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{
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struct ltc2688_state *st = iio_priv(indio_dev);
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int ret;
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switch (info) {
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case IIO_CHAN_INFO_RAW:
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ret = ltc2688_dac_code_read(st, chan->channel, LTC2688_INPUT_A,
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val);
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if (ret)
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return ret;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_OFFSET:
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ret = ltc2688_offset_get(st, chan->channel, val);
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if (ret)
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return ret;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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ret = ltc2688_scale_get(st, chan->channel, val);
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if (ret)
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return ret;
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*val2 = 16;
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return IIO_VAL_FRACTIONAL_LOG2;
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case IIO_CHAN_INFO_CALIBBIAS:
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ret = regmap_read(st->regmap,
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LTC2688_CMD_CH_OFFSET(chan->channel), val);
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if (ret)
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return ret;
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*val = FIELD_GET(LTC2688_CH_CALIBBIAS_MASK, *val);
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_CALIBSCALE:
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ret = regmap_read(st->regmap,
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LTC2688_CMD_CH_GAIN(chan->channel), val);
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if (ret)
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return ret;
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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}
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static int ltc2688_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int val,
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int val2, long info)
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{
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struct ltc2688_state *st = iio_priv(indio_dev);
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switch (info) {
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case IIO_CHAN_INFO_RAW:
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if (val > U16_MAX || val < 0)
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return -EINVAL;
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return ltc2688_dac_code_write(st, chan->channel,
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LTC2688_INPUT_A, val);
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case IIO_CHAN_INFO_CALIBBIAS:
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if (val > LTC2688_CH_CALIBBIAS_MAX_VAL)
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return -EINVAL;
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return regmap_write(st->regmap,
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LTC2688_CMD_CH_OFFSET(chan->channel),
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FIELD_PREP(LTC2688_CH_CALIBBIAS_MASK, val));
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case IIO_CHAN_INFO_CALIBSCALE:
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return regmap_write(st->regmap,
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LTC2688_CMD_CH_GAIN(chan->channel), val);
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default:
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return -EINVAL;
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}
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}
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static ssize_t ltc2688_dither_toggle_set(struct iio_dev *indio_dev,
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uintptr_t private,
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const struct iio_chan_spec *chan,
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const char *buf, size_t len)
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{
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struct ltc2688_state *st = iio_priv(indio_dev);
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struct ltc2688_chan *c = &st->channels[chan->channel];
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int ret;
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bool en;
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ret = kstrtobool(buf, &en);
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if (ret)
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return ret;
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mutex_lock(&st->lock);
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ret = regmap_update_bits(st->regmap, LTC2688_CMD_TOGGLE_DITHER_EN,
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BIT(chan->channel), en << chan->channel);
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if (ret)
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goto out_unlock;
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c->mode = en ? LTC2688_MODE_DITHER_TOGGLE : LTC2688_MODE_DEFAULT;
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out_unlock:
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mutex_unlock(&st->lock);
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return ret ?: len;
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}
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static ssize_t ltc2688_reg_bool_get(struct iio_dev *indio_dev,
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uintptr_t private,
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const struct iio_chan_spec *chan,
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char *buf)
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{
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const struct ltc2688_state *st = iio_priv(indio_dev);
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int ret;
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u32 val;
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ret = regmap_read(st->regmap, private, &val);
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if (ret)
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return ret;
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return sysfs_emit(buf, "%u\n", !!(val & BIT(chan->channel)));
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}
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static ssize_t ltc2688_reg_bool_set(struct iio_dev *indio_dev,
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uintptr_t private,
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const struct iio_chan_spec *chan,
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const char *buf, size_t len)
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{
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const struct ltc2688_state *st = iio_priv(indio_dev);
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int ret;
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bool en;
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ret = kstrtobool(buf, &en);
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if (ret)
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return ret;
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ret = regmap_update_bits(st->regmap, private, BIT(chan->channel),
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en << chan->channel);
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if (ret)
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return ret;
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return len;
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}
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static ssize_t ltc2688_dither_freq_avail(const struct ltc2688_state *st,
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const struct ltc2688_chan *chan,
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char *buf)
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{
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int sz = 0;
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u32 f;
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for (f = 0; f < ARRAY_SIZE(chan->dither_frequency); f++)
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sz += sysfs_emit_at(buf, sz, "%ld ", chan->dither_frequency[f]);
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buf[sz - 1] = '\n';
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return sz;
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}
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static ssize_t ltc2688_dither_freq_get(struct iio_dev *indio_dev,
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uintptr_t private,
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const struct iio_chan_spec *chan,
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char *buf)
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{
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const struct ltc2688_state *st = iio_priv(indio_dev);
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const struct ltc2688_chan *c = &st->channels[chan->channel];
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u32 reg, freq;
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int ret;
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if (private == LTC2688_DITHER_FREQ_AVAIL)
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return ltc2688_dither_freq_avail(st, c, buf);
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ret = regmap_read(st->regmap, LTC2688_CMD_CH_SETTING(chan->channel),
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®);
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if (ret)
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return ret;
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freq = FIELD_GET(LTC2688_CH_DIT_PER_MSK, reg);
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if (freq >= ARRAY_SIZE(c->dither_frequency))
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return -EIO;
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return sysfs_emit(buf, "%ld\n", c->dither_frequency[freq]);
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}
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static ssize_t ltc2688_dither_freq_set(struct iio_dev *indio_dev,
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uintptr_t private,
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const struct iio_chan_spec *chan,
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const char *buf, size_t len)
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{
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const struct ltc2688_state *st = iio_priv(indio_dev);
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const struct ltc2688_chan *c = &st->channels[chan->channel];
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long val;
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u32 freq;
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int ret;
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if (private == LTC2688_DITHER_FREQ_AVAIL)
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return -EINVAL;
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ret = kstrtol(buf, 10, &val);
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if (ret)
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return ret;
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for (freq = 0; freq < ARRAY_SIZE(c->dither_frequency); freq++) {
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if (val == c->dither_frequency[freq])
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break;
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}
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if (freq == ARRAY_SIZE(c->dither_frequency))
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return -EINVAL;
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ret = regmap_update_bits(st->regmap,
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LTC2688_CMD_CH_SETTING(chan->channel),
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LTC2688_CH_DIT_PER_MSK,
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FIELD_PREP(LTC2688_CH_DIT_PER_MSK, freq));
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if (ret)
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return ret;
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return len;
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}
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|
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static ssize_t ltc2688_dac_input_read(struct iio_dev *indio_dev,
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uintptr_t private,
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const struct iio_chan_spec *chan,
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char *buf)
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{
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struct ltc2688_state *st = iio_priv(indio_dev);
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int ret;
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u32 val;
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|
|
|
if (private == LTC2688_INPUT_B_AVAIL)
|
|
return sysfs_emit(buf, "[%u %u %u]\n", ltc2688_raw_range[0],
|
|
ltc2688_raw_range[1],
|
|
ltc2688_raw_range[2] / 4);
|
|
|
|
if (private == LTC2688_DITHER_OFF)
|
|
return sysfs_emit(buf, "0\n");
|
|
|
|
ret = ltc2688_dac_code_read(st, chan->channel, private, &val);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return sysfs_emit(buf, "%u\n", val);
|
|
}
|
|
|
|
static ssize_t ltc2688_dac_input_write(struct iio_dev *indio_dev,
|
|
uintptr_t private,
|
|
const struct iio_chan_spec *chan,
|
|
const char *buf, size_t len)
|
|
{
|
|
struct ltc2688_state *st = iio_priv(indio_dev);
|
|
int ret;
|
|
u16 val;
|
|
|
|
if (private == LTC2688_INPUT_B_AVAIL || private == LTC2688_DITHER_OFF)
|
|
return -EINVAL;
|
|
|
|
ret = kstrtou16(buf, 10, &val);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = ltc2688_dac_code_write(st, chan->channel, private, val);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return len;
|
|
}
|
|
|
|
static int ltc2688_get_dither_phase(struct iio_dev *dev,
|
|
const struct iio_chan_spec *chan)
|
|
{
|
|
struct ltc2688_state *st = iio_priv(dev);
|
|
int ret, regval;
|
|
|
|
ret = regmap_read(st->regmap, LTC2688_CMD_CH_SETTING(chan->channel),
|
|
®val);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return FIELD_GET(LTC2688_CH_DIT_PH_MSK, regval);
|
|
}
|
|
|
|
static int ltc2688_set_dither_phase(struct iio_dev *dev,
|
|
const struct iio_chan_spec *chan,
|
|
unsigned int phase)
|
|
{
|
|
struct ltc2688_state *st = iio_priv(dev);
|
|
|
|
return regmap_update_bits(st->regmap,
|
|
LTC2688_CMD_CH_SETTING(chan->channel),
|
|
LTC2688_CH_DIT_PH_MSK,
|
|
FIELD_PREP(LTC2688_CH_DIT_PH_MSK, phase));
|
|
}
|
|
|
|
static int ltc2688_reg_access(struct iio_dev *indio_dev,
|
|
unsigned int reg,
|
|
unsigned int writeval,
|
|
unsigned int *readval)
|
|
{
|
|
struct ltc2688_state *st = iio_priv(indio_dev);
|
|
|
|
if (readval)
|
|
return regmap_read(st->regmap, reg, readval);
|
|
|
|
return regmap_write(st->regmap, reg, writeval);
|
|
}
|
|
|
|
static const char * const ltc2688_dither_phase[] = {
|
|
"0", "1.5708", "3.14159", "4.71239",
|
|
};
|
|
|
|
static const struct iio_enum ltc2688_dither_phase_enum = {
|
|
.items = ltc2688_dither_phase,
|
|
.num_items = ARRAY_SIZE(ltc2688_dither_phase),
|
|
.set = ltc2688_set_dither_phase,
|
|
.get = ltc2688_get_dither_phase,
|
|
};
|
|
|
|
#define LTC2688_CHAN_EXT_INFO(_name, _what, _shared, _read, _write) { \
|
|
.name = _name, \
|
|
.read = (_read), \
|
|
.write = (_write), \
|
|
.private = (_what), \
|
|
.shared = (_shared), \
|
|
}
|
|
|
|
/*
|
|
* For toggle mode we only expose the symbol attr (sw_toggle) in case a TGPx is
|
|
* not provided in dts.
|
|
*/
|
|
static const struct iio_chan_spec_ext_info ltc2688_toggle_sym_ext_info[] = {
|
|
LTC2688_CHAN_EXT_INFO("raw0", LTC2688_INPUT_A, IIO_SEPARATE,
|
|
ltc2688_dac_input_read, ltc2688_dac_input_write),
|
|
LTC2688_CHAN_EXT_INFO("raw1", LTC2688_INPUT_B, IIO_SEPARATE,
|
|
ltc2688_dac_input_read, ltc2688_dac_input_write),
|
|
LTC2688_CHAN_EXT_INFO("toggle_en", LTC2688_CMD_TOGGLE_DITHER_EN,
|
|
IIO_SEPARATE, ltc2688_reg_bool_get,
|
|
ltc2688_dither_toggle_set),
|
|
LTC2688_CHAN_EXT_INFO("powerdown", LTC2688_CMD_POWERDOWN, IIO_SEPARATE,
|
|
ltc2688_reg_bool_get, ltc2688_reg_bool_set),
|
|
LTC2688_CHAN_EXT_INFO("symbol", LTC2688_CMD_SW_TOGGLE, IIO_SEPARATE,
|
|
ltc2688_reg_bool_get, ltc2688_reg_bool_set),
|
|
{}
|
|
};
|
|
|
|
static const struct iio_chan_spec_ext_info ltc2688_toggle_ext_info[] = {
|
|
LTC2688_CHAN_EXT_INFO("raw0", LTC2688_INPUT_A, IIO_SEPARATE,
|
|
ltc2688_dac_input_read, ltc2688_dac_input_write),
|
|
LTC2688_CHAN_EXT_INFO("raw1", LTC2688_INPUT_B, IIO_SEPARATE,
|
|
ltc2688_dac_input_read, ltc2688_dac_input_write),
|
|
LTC2688_CHAN_EXT_INFO("toggle_en", LTC2688_CMD_TOGGLE_DITHER_EN,
|
|
IIO_SEPARATE, ltc2688_reg_bool_get,
|
|
ltc2688_dither_toggle_set),
|
|
LTC2688_CHAN_EXT_INFO("powerdown", LTC2688_CMD_POWERDOWN, IIO_SEPARATE,
|
|
ltc2688_reg_bool_get, ltc2688_reg_bool_set),
|
|
{}
|
|
};
|
|
|
|
static struct iio_chan_spec_ext_info ltc2688_dither_ext_info[] = {
|
|
LTC2688_CHAN_EXT_INFO("dither_raw", LTC2688_INPUT_B, IIO_SEPARATE,
|
|
ltc2688_dac_input_read, ltc2688_dac_input_write),
|
|
LTC2688_CHAN_EXT_INFO("dither_raw_available", LTC2688_INPUT_B_AVAIL,
|
|
IIO_SEPARATE, ltc2688_dac_input_read,
|
|
ltc2688_dac_input_write),
|
|
LTC2688_CHAN_EXT_INFO("dither_offset", LTC2688_DITHER_OFF, IIO_SEPARATE,
|
|
ltc2688_dac_input_read, ltc2688_dac_input_write),
|
|
/*
|
|
* Not IIO_ENUM because the available freq needs to be computed at
|
|
* probe. We could still use it, but it didn't felt much right.
|
|
*/
|
|
LTC2688_CHAN_EXT_INFO("dither_frequency", 0, IIO_SEPARATE,
|
|
ltc2688_dither_freq_get, ltc2688_dither_freq_set),
|
|
LTC2688_CHAN_EXT_INFO("dither_frequency_available",
|
|
LTC2688_DITHER_FREQ_AVAIL, IIO_SEPARATE,
|
|
ltc2688_dither_freq_get, ltc2688_dither_freq_set),
|
|
IIO_ENUM("dither_phase", IIO_SEPARATE, <c2688_dither_phase_enum),
|
|
IIO_ENUM_AVAILABLE("dither_phase", IIO_SEPARATE,
|
|
<c2688_dither_phase_enum),
|
|
LTC2688_CHAN_EXT_INFO("dither_en", LTC2688_CMD_TOGGLE_DITHER_EN,
|
|
IIO_SEPARATE, ltc2688_reg_bool_get,
|
|
ltc2688_dither_toggle_set),
|
|
LTC2688_CHAN_EXT_INFO("powerdown", LTC2688_CMD_POWERDOWN, IIO_SEPARATE,
|
|
ltc2688_reg_bool_get, ltc2688_reg_bool_set),
|
|
{}
|
|
};
|
|
|
|
static const struct iio_chan_spec_ext_info ltc2688_ext_info[] = {
|
|
LTC2688_CHAN_EXT_INFO("powerdown", LTC2688_CMD_POWERDOWN, IIO_SEPARATE,
|
|
ltc2688_reg_bool_get, ltc2688_reg_bool_set),
|
|
{}
|
|
};
|
|
|
|
#define LTC2688_CHANNEL(_chan) { \
|
|
.type = IIO_VOLTAGE, \
|
|
.indexed = 1, \
|
|
.output = 1, \
|
|
.channel = (_chan), \
|
|
.info_mask_separate = BIT(IIO_CHAN_INFO_CALIBSCALE) | \
|
|
BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET) | \
|
|
BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_RAW), \
|
|
.info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW), \
|
|
.ext_info = ltc2688_ext_info, \
|
|
}
|
|
|
|
static const struct iio_chan_spec ltc2688_channels[] = {
|
|
LTC2688_CHANNEL(0),
|
|
LTC2688_CHANNEL(1),
|
|
LTC2688_CHANNEL(2),
|
|
LTC2688_CHANNEL(3),
|
|
LTC2688_CHANNEL(4),
|
|
LTC2688_CHANNEL(5),
|
|
LTC2688_CHANNEL(6),
|
|
LTC2688_CHANNEL(7),
|
|
LTC2688_CHANNEL(8),
|
|
LTC2688_CHANNEL(9),
|
|
LTC2688_CHANNEL(10),
|
|
LTC2688_CHANNEL(11),
|
|
LTC2688_CHANNEL(12),
|
|
LTC2688_CHANNEL(13),
|
|
LTC2688_CHANNEL(14),
|
|
LTC2688_CHANNEL(15),
|
|
};
|
|
|
|
static void ltc2688_clk_disable(void *clk)
|
|
{
|
|
clk_disable_unprepare(clk);
|
|
}
|
|
|
|
static const int ltc2688_period[LTC2688_DITHER_FREQ_AVAIL_N] = {
|
|
4, 8, 16, 32, 64,
|
|
};
|
|
|
|
static int ltc2688_tgp_clk_setup(struct ltc2688_state *st,
|
|
struct ltc2688_chan *chan,
|
|
struct fwnode_handle *node, int tgp)
|
|
{
|
|
unsigned long rate;
|
|
struct clk *clk;
|
|
int ret, f;
|
|
|
|
clk = devm_get_clk_from_child(&st->spi->dev, to_of_node(node), NULL);
|
|
if (IS_ERR(clk))
|
|
return dev_err_probe(&st->spi->dev, PTR_ERR(clk),
|
|
"failed to get tgp clk.\n");
|
|
|
|
ret = clk_prepare_enable(clk);
|
|
if (ret)
|
|
return dev_err_probe(&st->spi->dev, ret,
|
|
"failed to enable tgp clk.\n");
|
|
|
|
ret = devm_add_action_or_reset(&st->spi->dev, ltc2688_clk_disable, clk);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (chan->toggle_chan)
|
|
return 0;
|
|
|
|
/* calculate available dither frequencies */
|
|
rate = clk_get_rate(clk);
|
|
for (f = 0; f < ARRAY_SIZE(chan->dither_frequency); f++)
|
|
chan->dither_frequency[f] = DIV_ROUND_CLOSEST(rate, ltc2688_period[f]);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ltc2688_span_lookup(const struct ltc2688_state *st, int min, int max)
|
|
{
|
|
u32 span;
|
|
|
|
for (span = 0; span < ARRAY_SIZE(ltc2688_span_helper); span++) {
|
|
if (min == ltc2688_span_helper[span][0] &&
|
|
max == ltc2688_span_helper[span][1])
|
|
return span;
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int ltc2688_channel_config(struct ltc2688_state *st)
|
|
{
|
|
struct device *dev = &st->spi->dev;
|
|
struct fwnode_handle *child;
|
|
u32 reg, clk_input, val, tmp[2];
|
|
int ret, span;
|
|
|
|
device_for_each_child_node(dev, child) {
|
|
struct ltc2688_chan *chan;
|
|
|
|
ret = fwnode_property_read_u32(child, "reg", ®);
|
|
if (ret) {
|
|
fwnode_handle_put(child);
|
|
return dev_err_probe(dev, ret,
|
|
"Failed to get reg property\n");
|
|
}
|
|
|
|
if (reg >= LTC2688_DAC_CHANNELS) {
|
|
fwnode_handle_put(child);
|
|
return dev_err_probe(dev, -EINVAL,
|
|
"reg bigger than: %d\n",
|
|
LTC2688_DAC_CHANNELS);
|
|
}
|
|
|
|
val = 0;
|
|
chan = &st->channels[reg];
|
|
if (fwnode_property_read_bool(child, "adi,toggle-mode")) {
|
|
chan->toggle_chan = true;
|
|
/* assume sw toggle ABI */
|
|
st->iio_chan[reg].ext_info = ltc2688_toggle_sym_ext_info;
|
|
/*
|
|
* Clear IIO_CHAN_INFO_RAW bit as toggle channels expose
|
|
* out_voltage_raw{0|1} files.
|
|
*/
|
|
__clear_bit(IIO_CHAN_INFO_RAW,
|
|
&st->iio_chan[reg].info_mask_separate);
|
|
}
|
|
|
|
ret = fwnode_property_read_u32_array(child, "adi,output-range-microvolt",
|
|
tmp, ARRAY_SIZE(tmp));
|
|
if (!ret) {
|
|
span = ltc2688_span_lookup(st, (int)tmp[0] / 1000,
|
|
tmp[1] / 1000);
|
|
if (span < 0) {
|
|
fwnode_handle_put(child);
|
|
return dev_err_probe(dev, -EINVAL,
|
|
"output range not valid:[%d %d]\n",
|
|
tmp[0], tmp[1]);
|
|
}
|
|
|
|
val |= FIELD_PREP(LTC2688_CH_SPAN_MSK, span);
|
|
}
|
|
|
|
ret = fwnode_property_read_u32(child, "adi,toggle-dither-input",
|
|
&clk_input);
|
|
if (!ret) {
|
|
if (clk_input >= LTC2688_CH_TGP_MAX) {
|
|
fwnode_handle_put(child);
|
|
return dev_err_probe(dev, -EINVAL,
|
|
"toggle-dither-input inv value(%d)\n",
|
|
clk_input);
|
|
}
|
|
|
|
ret = ltc2688_tgp_clk_setup(st, chan, child, clk_input);
|
|
if (ret) {
|
|
fwnode_handle_put(child);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* 0 means software toggle which is the default mode.
|
|
* Hence the +1.
|
|
*/
|
|
val |= FIELD_PREP(LTC2688_CH_TD_SEL_MSK, clk_input + 1);
|
|
|
|
/*
|
|
* If a TGPx is given, we automatically assume a dither
|
|
* capable channel (unless toggle is already enabled).
|
|
* On top of this we just set here the dither bit in the
|
|
* channel settings. It won't have any effect until the
|
|
* global toggle/dither bit is enabled.
|
|
*/
|
|
if (!chan->toggle_chan) {
|
|
val |= FIELD_PREP(LTC2688_CH_MODE_MSK, 1);
|
|
st->iio_chan[reg].ext_info = ltc2688_dither_ext_info;
|
|
} else {
|
|
/* wait, no sw toggle after all */
|
|
st->iio_chan[reg].ext_info = ltc2688_toggle_ext_info;
|
|
}
|
|
}
|
|
|
|
if (fwnode_property_read_bool(child, "adi,overrange")) {
|
|
chan->overrange = true;
|
|
val |= LTC2688_CH_OVERRANGE_MSK;
|
|
}
|
|
|
|
if (!val)
|
|
continue;
|
|
|
|
ret = regmap_write(st->regmap, LTC2688_CMD_CH_SETTING(reg),
|
|
val);
|
|
if (ret) {
|
|
fwnode_handle_put(child);
|
|
return dev_err_probe(dev, -EINVAL,
|
|
"failed to set chan settings\n");
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ltc2688_setup(struct ltc2688_state *st, struct regulator *vref)
|
|
{
|
|
struct gpio_desc *gpio;
|
|
int ret;
|
|
|
|
/*
|
|
* If we have a reset pin, use that to reset the board, If not, use
|
|
* the reset bit.
|
|
*/
|
|
gpio = devm_gpiod_get_optional(&st->spi->dev, "clr", GPIOD_OUT_HIGH);
|
|
if (IS_ERR(gpio))
|
|
return dev_err_probe(&st->spi->dev, PTR_ERR(gpio),
|
|
"Failed to get reset gpio");
|
|
if (gpio) {
|
|
usleep_range(1000, 1200);
|
|
/* bring device out of reset */
|
|
gpiod_set_value_cansleep(gpio, 0);
|
|
} else {
|
|
ret = regmap_update_bits(st->regmap, LTC2688_CMD_CONFIG,
|
|
LTC2688_CONFIG_RST,
|
|
LTC2688_CONFIG_RST);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
usleep_range(10000, 12000);
|
|
|
|
/*
|
|
* Duplicate the default channel configuration as it can change during
|
|
* @ltc2688_channel_config()
|
|
*/
|
|
st->iio_chan = devm_kmemdup(&st->spi->dev, ltc2688_channels,
|
|
sizeof(ltc2688_channels), GFP_KERNEL);
|
|
if (!st->iio_chan)
|
|
return -ENOMEM;
|
|
|
|
ret = ltc2688_channel_config(st);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (!vref)
|
|
return 0;
|
|
|
|
return regmap_set_bits(st->regmap, LTC2688_CMD_CONFIG,
|
|
LTC2688_CONFIG_EXT_REF);
|
|
}
|
|
|
|
static void ltc2688_disable_regulators(void *data)
|
|
{
|
|
struct ltc2688_state *st = data;
|
|
|
|
regulator_bulk_disable(ARRAY_SIZE(st->regulators), st->regulators);
|
|
}
|
|
|
|
static void ltc2688_disable_regulator(void *regulator)
|
|
{
|
|
regulator_disable(regulator);
|
|
}
|
|
|
|
static bool ltc2688_reg_readable(struct device *dev, unsigned int reg)
|
|
{
|
|
switch (reg) {
|
|
case LTC2688_CMD_CH_CODE(0) ... LTC2688_CMD_CH_GAIN(15):
|
|
return true;
|
|
case LTC2688_CMD_CONFIG ... LTC2688_CMD_THERMAL_STAT:
|
|
return true;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static bool ltc2688_reg_writable(struct device *dev, unsigned int reg)
|
|
{
|
|
/*
|
|
* There's a jump from 0x76 to 0x78 in the write codes and the thermal
|
|
* status code is 0x77 (which is read only) so that we need to check
|
|
* that special condition.
|
|
*/
|
|
if (reg <= LTC2688_CMD_UPDATE_ALL && reg != LTC2688_CMD_THERMAL_STAT)
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
static struct regmap_bus ltc2688_regmap_bus = {
|
|
.read = ltc2688_spi_read,
|
|
.write = ltc2688_spi_write,
|
|
.read_flag_mask = LTC2688_READ_OPERATION,
|
|
.reg_format_endian_default = REGMAP_ENDIAN_BIG,
|
|
.val_format_endian_default = REGMAP_ENDIAN_BIG,
|
|
};
|
|
|
|
static const struct regmap_config ltc2688_regmap_config = {
|
|
.reg_bits = 8,
|
|
.val_bits = 16,
|
|
.readable_reg = ltc2688_reg_readable,
|
|
.writeable_reg = ltc2688_reg_writable,
|
|
/* ignoring the no op command */
|
|
.max_register = LTC2688_CMD_UPDATE_ALL,
|
|
};
|
|
|
|
static const struct iio_info ltc2688_info = {
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.write_raw = ltc2688_write_raw,
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.read_raw = ltc2688_read_raw,
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.read_avail = ltc2688_read_avail,
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.debugfs_reg_access = ltc2688_reg_access,
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};
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|
|
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static int ltc2688_probe(struct spi_device *spi)
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|
{
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struct ltc2688_state *st;
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struct iio_dev *indio_dev;
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struct regulator *vref_reg;
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struct device *dev = &spi->dev;
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int ret;
|
|
|
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indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
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if (!indio_dev)
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return -ENOMEM;
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|
|
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st = iio_priv(indio_dev);
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|
st->spi = spi;
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|
|
|
/* Just write this once. No need to do it in every regmap read. */
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|
st->tx_data[3] = LTC2688_CMD_NOOP;
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mutex_init(&st->lock);
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|
|
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st->regmap = devm_regmap_init(dev, <c2688_regmap_bus, st,
|
|
<c2688_regmap_config);
|
|
if (IS_ERR(st->regmap))
|
|
return dev_err_probe(dev, PTR_ERR(st->regmap),
|
|
"Failed to init regmap");
|
|
|
|
st->regulators[0].supply = "vcc";
|
|
st->regulators[1].supply = "iovcc";
|
|
ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(st->regulators),
|
|
st->regulators);
|
|
if (ret)
|
|
return dev_err_probe(dev, ret, "Failed to get regulators\n");
|
|
|
|
ret = regulator_bulk_enable(ARRAY_SIZE(st->regulators), st->regulators);
|
|
if (ret)
|
|
return dev_err_probe(dev, ret, "Failed to enable regulators\n");
|
|
|
|
ret = devm_add_action_or_reset(dev, ltc2688_disable_regulators, st);
|
|
if (ret)
|
|
return ret;
|
|
|
|
vref_reg = devm_regulator_get_optional(dev, "vref");
|
|
if (IS_ERR(vref_reg)) {
|
|
if (PTR_ERR(vref_reg) != -ENODEV)
|
|
return dev_err_probe(dev, PTR_ERR(vref_reg),
|
|
"Failed to get vref regulator");
|
|
|
|
vref_reg = NULL;
|
|
/* internal reference */
|
|
st->vref = 4096;
|
|
} else {
|
|
ret = regulator_enable(vref_reg);
|
|
if (ret)
|
|
return dev_err_probe(dev, ret,
|
|
"Failed to enable vref regulators\n");
|
|
|
|
ret = devm_add_action_or_reset(dev, ltc2688_disable_regulator,
|
|
vref_reg);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = regulator_get_voltage(vref_reg);
|
|
if (ret < 0)
|
|
return dev_err_probe(dev, ret, "Failed to get vref\n");
|
|
|
|
st->vref = ret / 1000;
|
|
}
|
|
|
|
ret = ltc2688_setup(st, vref_reg);
|
|
if (ret)
|
|
return ret;
|
|
|
|
indio_dev->name = "ltc2688";
|
|
indio_dev->info = <c2688_info;
|
|
indio_dev->modes = INDIO_DIRECT_MODE;
|
|
indio_dev->channels = st->iio_chan;
|
|
indio_dev->num_channels = ARRAY_SIZE(ltc2688_channels);
|
|
|
|
return devm_iio_device_register(dev, indio_dev);
|
|
}
|
|
|
|
static const struct of_device_id ltc2688_of_id[] = {
|
|
{ .compatible = "adi,ltc2688" },
|
|
{}
|
|
};
|
|
MODULE_DEVICE_TABLE(of, ltc2688_of_id);
|
|
|
|
static const struct spi_device_id ltc2688_id[] = {
|
|
{ "ltc2688" },
|
|
{}
|
|
};
|
|
MODULE_DEVICE_TABLE(spi, ltc2688_id);
|
|
|
|
static struct spi_driver ltc2688_driver = {
|
|
.driver = {
|
|
.name = "ltc2688",
|
|
.of_match_table = ltc2688_of_id,
|
|
},
|
|
.probe = ltc2688_probe,
|
|
.id_table = ltc2688_id,
|
|
};
|
|
module_spi_driver(ltc2688_driver);
|
|
|
|
MODULE_AUTHOR("Nuno Sá <nuno.sa@analog.com>");
|
|
MODULE_DESCRIPTION("Analog Devices LTC2688 DAC");
|
|
MODULE_LICENSE("GPL");
|