418 lines
9.5 KiB
C
418 lines
9.5 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2020 Marek Vasut <marex@denx.de>
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*
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* Based on rpi_touchscreen.c by Eric Anholt <eric@anholt.net>
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*/
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#include <linux/backlight.h>
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#include <linux/err.h>
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#include <linux/gpio.h>
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#include <linux/gpio/driver.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/regmap.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/machine.h>
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#include <linux/regulator/of_regulator.h>
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#include <linux/slab.h>
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/* I2C registers of the Atmel microcontroller. */
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#define REG_ID 0x80
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#define REG_PORTA 0x81
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#define REG_PORTB 0x82
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#define REG_PORTC 0x83
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#define REG_POWERON 0x85
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#define REG_PWM 0x86
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#define REG_ADDR_L 0x8c
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#define REG_ADDR_H 0x8d
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#define REG_WRITE_DATA_H 0x90
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#define REG_WRITE_DATA_L 0x91
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#define PA_LCD_DITHB BIT(0)
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#define PA_LCD_MODE BIT(1)
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#define PA_LCD_LR BIT(2)
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#define PA_LCD_UD BIT(3)
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#define PB_BRIDGE_PWRDNX_N BIT(0)
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#define PB_LCD_VCC_N BIT(1)
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#define PB_LCD_MAIN BIT(7)
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#define PC_LED_EN BIT(0)
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#define PC_RST_TP_N BIT(1)
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#define PC_RST_LCD_N BIT(2)
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#define PC_RST_BRIDGE_N BIT(3)
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enum gpio_signals {
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RST_BRIDGE_N, /* TC358762 bridge reset */
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RST_TP_N, /* Touch controller reset */
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NUM_GPIO
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};
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struct gpio_signal_mappings {
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unsigned int reg;
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unsigned int mask;
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};
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static const struct gpio_signal_mappings mappings[NUM_GPIO] = {
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[RST_BRIDGE_N] = { REG_PORTC, PC_RST_BRIDGE_N | PC_RST_LCD_N },
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[RST_TP_N] = { REG_PORTC, PC_RST_TP_N },
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};
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struct attiny_lcd {
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/* lock to serialise overall accesses to the Atmel */
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struct mutex lock;
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struct regmap *regmap;
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bool gpio_states[NUM_GPIO];
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u8 port_states[3];
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struct gpio_chip gc;
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};
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static const struct regmap_config attiny_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.disable_locking = 1,
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.max_register = REG_WRITE_DATA_L,
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.cache_type = REGCACHE_RBTREE,
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};
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static int attiny_set_port_state(struct attiny_lcd *state, int reg, u8 val)
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{
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state->port_states[reg - REG_PORTA] = val;
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return regmap_write(state->regmap, reg, val);
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};
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static u8 attiny_get_port_state(struct attiny_lcd *state, int reg)
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{
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return state->port_states[reg - REG_PORTA];
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};
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static int attiny_lcd_power_enable(struct regulator_dev *rdev)
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{
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struct attiny_lcd *state = rdev_get_drvdata(rdev);
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mutex_lock(&state->lock);
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/* Ensure bridge, and tp stay in reset */
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attiny_set_port_state(state, REG_PORTC, 0);
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usleep_range(5000, 10000);
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/* Default to the same orientation as the closed source
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* firmware used for the panel. Runtime rotation
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* configuration will be supported using VC4's plane
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* orientation bits.
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*/
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attiny_set_port_state(state, REG_PORTA, PA_LCD_LR);
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usleep_range(5000, 10000);
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/* Main regulator on, and power to the panel (LCD_VCC_N) */
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attiny_set_port_state(state, REG_PORTB, PB_LCD_MAIN);
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usleep_range(5000, 10000);
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/* Bring controllers out of reset */
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attiny_set_port_state(state, REG_PORTC, PC_LED_EN);
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msleep(80);
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mutex_unlock(&state->lock);
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return 0;
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}
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static int attiny_lcd_power_disable(struct regulator_dev *rdev)
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{
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struct attiny_lcd *state = rdev_get_drvdata(rdev);
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mutex_lock(&state->lock);
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regmap_write(rdev->regmap, REG_PWM, 0);
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usleep_range(5000, 10000);
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attiny_set_port_state(state, REG_PORTA, 0);
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usleep_range(5000, 10000);
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attiny_set_port_state(state, REG_PORTB, PB_LCD_VCC_N);
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usleep_range(5000, 10000);
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attiny_set_port_state(state, REG_PORTC, 0);
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msleep(30);
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mutex_unlock(&state->lock);
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return 0;
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}
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static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
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{
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struct attiny_lcd *state = rdev_get_drvdata(rdev);
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unsigned int data;
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int ret, i;
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mutex_lock(&state->lock);
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for (i = 0; i < 10; i++) {
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ret = regmap_read(rdev->regmap, REG_PORTC, &data);
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if (!ret)
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break;
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usleep_range(10000, 12000);
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}
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mutex_unlock(&state->lock);
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if (ret < 0)
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return ret;
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return data & PC_RST_BRIDGE_N;
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}
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static const struct regulator_init_data attiny_regulator_default = {
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.constraints = {
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.valid_ops_mask = REGULATOR_CHANGE_STATUS,
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},
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};
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static const struct regulator_ops attiny_regulator_ops = {
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.enable = attiny_lcd_power_enable,
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.disable = attiny_lcd_power_disable,
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.is_enabled = attiny_lcd_power_is_enabled,
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};
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static const struct regulator_desc attiny_regulator = {
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.name = "tc358762-power",
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.ops = &attiny_regulator_ops,
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.type = REGULATOR_VOLTAGE,
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.owner = THIS_MODULE,
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};
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static int attiny_update_status(struct backlight_device *bl)
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{
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struct attiny_lcd *state = bl_get_data(bl);
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struct regmap *regmap = state->regmap;
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int brightness = bl->props.brightness;
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int ret, i;
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mutex_lock(&state->lock);
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if (bl->props.power != FB_BLANK_UNBLANK ||
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bl->props.fb_blank != FB_BLANK_UNBLANK)
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brightness = 0;
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for (i = 0; i < 10; i++) {
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ret = regmap_write(regmap, REG_PWM, brightness);
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if (!ret)
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break;
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}
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mutex_unlock(&state->lock);
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return ret;
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}
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static const struct backlight_ops attiny_bl = {
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.update_status = attiny_update_status,
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};
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static int attiny_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
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{
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return GPIO_LINE_DIRECTION_OUT;
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}
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static void attiny_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
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{
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struct attiny_lcd *state = gpiochip_get_data(gc);
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u8 last_val;
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if (off >= NUM_GPIO)
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return;
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mutex_lock(&state->lock);
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last_val = attiny_get_port_state(state, mappings[off].reg);
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if (val)
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last_val |= mappings[off].mask;
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else
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last_val &= ~mappings[off].mask;
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attiny_set_port_state(state, mappings[off].reg, last_val);
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if (off == RST_BRIDGE_N && val) {
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usleep_range(5000, 8000);
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regmap_write(state->regmap, REG_ADDR_H, 0x04);
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usleep_range(5000, 8000);
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regmap_write(state->regmap, REG_ADDR_L, 0x7c);
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usleep_range(5000, 8000);
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regmap_write(state->regmap, REG_WRITE_DATA_H, 0x00);
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usleep_range(5000, 8000);
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regmap_write(state->regmap, REG_WRITE_DATA_L, 0x00);
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msleep(100);
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}
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mutex_unlock(&state->lock);
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}
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static int attiny_i2c_read(struct i2c_client *client, u8 reg, unsigned int *buf)
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{
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struct i2c_msg msgs[1];
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u8 addr_buf[1] = { reg };
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u8 data_buf[1] = { 0, };
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int ret;
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/* Write register address */
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msgs[0].addr = client->addr;
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msgs[0].flags = 0;
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msgs[0].len = ARRAY_SIZE(addr_buf);
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msgs[0].buf = addr_buf;
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ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
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if (ret != ARRAY_SIZE(msgs))
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return -EIO;
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usleep_range(5000, 10000);
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/* Read data from register */
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msgs[0].addr = client->addr;
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msgs[0].flags = I2C_M_RD;
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msgs[0].len = 1;
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msgs[0].buf = data_buf;
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ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
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if (ret != ARRAY_SIZE(msgs))
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return -EIO;
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*buf = data_buf[0];
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return 0;
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}
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/*
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* I2C driver interface functions
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*/
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static int attiny_i2c_probe(struct i2c_client *i2c,
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const struct i2c_device_id *id)
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{
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struct backlight_properties props = { };
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struct regulator_config config = { };
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struct backlight_device *bl;
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struct regulator_dev *rdev;
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struct attiny_lcd *state;
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struct regmap *regmap;
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unsigned int data;
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int ret;
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state = devm_kzalloc(&i2c->dev, sizeof(*state), GFP_KERNEL);
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if (!state)
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return -ENOMEM;
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mutex_init(&state->lock);
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i2c_set_clientdata(i2c, state);
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regmap = devm_regmap_init_i2c(i2c, &attiny_regmap_config);
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if (IS_ERR(regmap)) {
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ret = PTR_ERR(regmap);
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dev_err(&i2c->dev, "Failed to allocate register map: %d\n",
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ret);
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goto error;
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}
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ret = attiny_i2c_read(i2c, REG_ID, &data);
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if (ret < 0) {
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dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
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goto error;
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}
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switch (data) {
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case 0xde: /* ver 1 */
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case 0xc3: /* ver 2 */
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break;
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default:
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dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data);
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ret = -ENODEV;
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goto error;
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}
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regmap_write(regmap, REG_POWERON, 0);
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msleep(30);
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regmap_write(regmap, REG_PWM, 0);
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config.dev = &i2c->dev;
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config.regmap = regmap;
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config.of_node = i2c->dev.of_node;
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config.init_data = &attiny_regulator_default;
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config.driver_data = state;
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rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);
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if (IS_ERR(rdev)) {
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dev_err(&i2c->dev, "Failed to register ATTINY regulator\n");
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ret = PTR_ERR(rdev);
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goto error;
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}
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props.type = BACKLIGHT_RAW;
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props.max_brightness = 0xff;
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state->regmap = regmap;
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bl = devm_backlight_device_register(&i2c->dev, dev_name(&i2c->dev),
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&i2c->dev, state, &attiny_bl,
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&props);
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if (IS_ERR(bl)) {
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ret = PTR_ERR(bl);
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goto error;
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}
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bl->props.brightness = 0xff;
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state->gc.parent = &i2c->dev;
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state->gc.label = i2c->name;
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state->gc.owner = THIS_MODULE;
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state->gc.of_node = i2c->dev.of_node;
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state->gc.base = -1;
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state->gc.ngpio = NUM_GPIO;
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state->gc.set = attiny_gpio_set;
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state->gc.get_direction = attiny_gpio_get_direction;
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state->gc.can_sleep = true;
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ret = devm_gpiochip_add_data(&i2c->dev, &state->gc, state);
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if (ret) {
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dev_err(&i2c->dev, "Failed to create gpiochip: %d\n", ret);
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goto error;
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}
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return 0;
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error:
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mutex_destroy(&state->lock);
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return ret;
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}
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static int attiny_i2c_remove(struct i2c_client *client)
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{
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struct attiny_lcd *state = i2c_get_clientdata(client);
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mutex_destroy(&state->lock);
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return 0;
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}
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static const struct of_device_id attiny_dt_ids[] = {
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{ .compatible = "raspberrypi,7inch-touchscreen-panel-regulator" },
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{},
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};
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MODULE_DEVICE_TABLE(of, attiny_dt_ids);
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static struct i2c_driver attiny_regulator_driver = {
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.driver = {
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.name = "rpi_touchscreen_attiny",
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.of_match_table = of_match_ptr(attiny_dt_ids),
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},
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.probe = attiny_i2c_probe,
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.remove = attiny_i2c_remove,
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};
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module_i2c_driver(attiny_regulator_driver);
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MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
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MODULE_DESCRIPTION("Regulator device driver for Raspberry Pi 7-inch touchscreen");
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MODULE_LICENSE("GPL v2");
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