557 lines
14 KiB
C
557 lines
14 KiB
C
/*
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* I2C multiplexer
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*
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* Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
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* Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
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*
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* This module supports the PCA954x and PCA954x series of I2C multiplexer/switch
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* chips made by NXP Semiconductors.
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* This includes the:
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* PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547,
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* PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849.
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*
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* These chips are all controlled via the I2C bus itself, and all have a
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* single 8-bit register. The upstream "parent" bus fans out to two,
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* four, or eight downstream busses or channels; which of these
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* are selected is determined by the chip type and register contents. A
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* mux can select only one sub-bus at a time; a switch can select any
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* combination simultaneously.
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*
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* Based on:
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* pca954x.c from Kumar Gala <galak@kernel.crashing.org>
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* Copyright (C) 2006
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*
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* Based on:
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* pca954x.c from Ken Harrenstien
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* Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
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*
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* Based on:
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* i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
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* and
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* pca9540.c from Jean Delvare <jdelvare@suse.de>.
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/device.h>
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#include <linux/delay.h>
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#include <linux/gpio/consumer.h>
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#include <linux/i2c.h>
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#include <linux/i2c-mux.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/of_irq.h>
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#include <linux/pm.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <dt-bindings/mux/mux.h>
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#define PCA954X_MAX_NCHANS 8
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#define PCA954X_IRQ_OFFSET 4
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enum pca_type {
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pca_9540,
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pca_9542,
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pca_9543,
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pca_9544,
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pca_9545,
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pca_9546,
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pca_9547,
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pca_9548,
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pca_9846,
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pca_9847,
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pca_9848,
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pca_9849,
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};
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struct chip_desc {
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u8 nchans;
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u8 enable; /* used for muxes only */
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u8 has_irq;
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enum muxtype {
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pca954x_ismux = 0,
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pca954x_isswi
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} muxtype;
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struct i2c_device_identity id;
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};
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struct pca954x {
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const struct chip_desc *chip;
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u8 last_chan; /* last register value */
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/* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */
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s8 idle_state;
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struct i2c_client *client;
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struct irq_domain *irq;
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unsigned int irq_mask;
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raw_spinlock_t lock;
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};
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/* Provide specs for the PCA954x types we know about */
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static const struct chip_desc chips[] = {
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[pca_9540] = {
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.nchans = 2,
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.enable = 0x4,
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.muxtype = pca954x_ismux,
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.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
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},
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[pca_9542] = {
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.nchans = 2,
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.enable = 0x4,
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.has_irq = 1,
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.muxtype = pca954x_ismux,
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.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
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},
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[pca_9543] = {
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.nchans = 2,
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.has_irq = 1,
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.muxtype = pca954x_isswi,
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.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
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},
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[pca_9544] = {
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.nchans = 4,
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.enable = 0x4,
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.has_irq = 1,
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.muxtype = pca954x_ismux,
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.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
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},
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[pca_9545] = {
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.nchans = 4,
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.has_irq = 1,
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.muxtype = pca954x_isswi,
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.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
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},
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[pca_9546] = {
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.nchans = 4,
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.muxtype = pca954x_isswi,
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.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
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},
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[pca_9547] = {
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.nchans = 8,
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.enable = 0x8,
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.muxtype = pca954x_ismux,
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.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
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},
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[pca_9548] = {
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.nchans = 8,
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.muxtype = pca954x_isswi,
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.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
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},
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[pca_9846] = {
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.nchans = 4,
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.muxtype = pca954x_isswi,
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.id = {
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.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
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.part_id = 0x10b,
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},
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},
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[pca_9847] = {
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.nchans = 8,
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.enable = 0x8,
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.muxtype = pca954x_ismux,
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.id = {
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.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
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.part_id = 0x108,
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},
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},
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[pca_9848] = {
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.nchans = 8,
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.muxtype = pca954x_isswi,
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.id = {
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.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
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.part_id = 0x10a,
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},
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},
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[pca_9849] = {
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.nchans = 4,
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.enable = 0x4,
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.muxtype = pca954x_ismux,
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.id = {
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.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
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.part_id = 0x109,
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},
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},
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};
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static const struct i2c_device_id pca954x_id[] = {
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{ "pca9540", pca_9540 },
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{ "pca9542", pca_9542 },
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{ "pca9543", pca_9543 },
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{ "pca9544", pca_9544 },
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{ "pca9545", pca_9545 },
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{ "pca9546", pca_9546 },
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{ "pca9547", pca_9547 },
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{ "pca9548", pca_9548 },
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{ "pca9846", pca_9846 },
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{ "pca9847", pca_9847 },
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{ "pca9848", pca_9848 },
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{ "pca9849", pca_9849 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, pca954x_id);
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#ifdef CONFIG_OF
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static const struct of_device_id pca954x_of_match[] = {
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{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
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{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
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{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
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{ .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
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{ .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
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{ .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
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{ .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
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{ .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
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{ .compatible = "nxp,pca9846", .data = &chips[pca_9846] },
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{ .compatible = "nxp,pca9847", .data = &chips[pca_9847] },
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{ .compatible = "nxp,pca9848", .data = &chips[pca_9848] },
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{ .compatible = "nxp,pca9849", .data = &chips[pca_9849] },
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{}
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};
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MODULE_DEVICE_TABLE(of, pca954x_of_match);
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#endif
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/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
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for this as they will try to lock adapter a second time */
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static int pca954x_reg_write(struct i2c_adapter *adap,
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struct i2c_client *client, u8 val)
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{
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union i2c_smbus_data dummy;
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return __i2c_smbus_xfer(adap, client->addr, client->flags,
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I2C_SMBUS_WRITE, val,
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I2C_SMBUS_BYTE, &dummy);
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}
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static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
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{
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struct pca954x *data = i2c_mux_priv(muxc);
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struct i2c_client *client = data->client;
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const struct chip_desc *chip = data->chip;
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u8 regval;
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int ret = 0;
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/* we make switches look like muxes, not sure how to be smarter */
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if (chip->muxtype == pca954x_ismux)
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regval = chan | chip->enable;
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else
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regval = 1 << chan;
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/* Only select the channel if its different from the last channel */
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if (data->last_chan != regval) {
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ret = pca954x_reg_write(muxc->parent, client, regval);
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data->last_chan = ret < 0 ? 0 : regval;
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}
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return ret;
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}
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static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
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{
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struct pca954x *data = i2c_mux_priv(muxc);
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struct i2c_client *client = data->client;
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s8 idle_state;
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idle_state = READ_ONCE(data->idle_state);
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if (idle_state >= 0)
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/* Set the mux back to a predetermined channel */
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return pca954x_select_chan(muxc, idle_state);
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if (idle_state == MUX_IDLE_DISCONNECT) {
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/* Deselect active channel */
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data->last_chan = 0;
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return pca954x_reg_write(muxc->parent, client,
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data->last_chan);
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}
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/* otherwise leave as-is */
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return 0;
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}
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static ssize_t idle_state_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct i2c_mux_core *muxc = i2c_get_clientdata(client);
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struct pca954x *data = i2c_mux_priv(muxc);
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return sprintf(buf, "%d\n", READ_ONCE(data->idle_state));
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}
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static ssize_t idle_state_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct i2c_mux_core *muxc = i2c_get_clientdata(client);
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struct pca954x *data = i2c_mux_priv(muxc);
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int val;
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int ret;
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ret = kstrtoint(buf, 0, &val);
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if (ret < 0)
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return ret;
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if (val != MUX_IDLE_AS_IS && val != MUX_IDLE_DISCONNECT &&
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(val < 0 || val >= data->chip->nchans))
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return -EINVAL;
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i2c_lock_bus(muxc->parent, I2C_LOCK_SEGMENT);
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WRITE_ONCE(data->idle_state, val);
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/*
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* Set the mux into a state consistent with the new
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* idle_state.
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*/
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if (data->last_chan || val != MUX_IDLE_DISCONNECT)
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ret = pca954x_deselect_mux(muxc, 0);
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i2c_unlock_bus(muxc->parent, I2C_LOCK_SEGMENT);
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return ret < 0 ? ret : count;
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}
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static DEVICE_ATTR_RW(idle_state);
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static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
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{
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struct pca954x *data = dev_id;
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unsigned int child_irq;
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int ret, i, handled = 0;
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ret = i2c_smbus_read_byte(data->client);
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if (ret < 0)
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return IRQ_NONE;
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for (i = 0; i < data->chip->nchans; i++) {
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if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
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child_irq = irq_linear_revmap(data->irq, i);
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handle_nested_irq(child_irq);
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handled++;
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}
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}
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return handled ? IRQ_HANDLED : IRQ_NONE;
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}
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static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
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{
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if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
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return -EINVAL;
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return 0;
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}
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static struct irq_chip pca954x_irq_chip = {
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.name = "i2c-mux-pca954x",
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.irq_set_type = pca954x_irq_set_type,
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};
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static int pca954x_irq_setup(struct i2c_mux_core *muxc)
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{
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struct pca954x *data = i2c_mux_priv(muxc);
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struct i2c_client *client = data->client;
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int c, irq;
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if (!data->chip->has_irq || client->irq <= 0)
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return 0;
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raw_spin_lock_init(&data->lock);
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data->irq = irq_domain_add_linear(client->dev.of_node,
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data->chip->nchans,
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&irq_domain_simple_ops, data);
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if (!data->irq)
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return -ENODEV;
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for (c = 0; c < data->chip->nchans; c++) {
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irq = irq_create_mapping(data->irq, c);
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if (!irq) {
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dev_err(&client->dev, "failed irq create map\n");
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return -EINVAL;
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}
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irq_set_chip_data(irq, data);
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irq_set_chip_and_handler(irq, &pca954x_irq_chip,
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handle_simple_irq);
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}
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return 0;
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}
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static void pca954x_cleanup(struct i2c_mux_core *muxc)
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{
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struct pca954x *data = i2c_mux_priv(muxc);
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struct i2c_client *client = data->client;
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int c, irq;
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device_remove_file(&client->dev, &dev_attr_idle_state);
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if (data->irq) {
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for (c = 0; c < data->chip->nchans; c++) {
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irq = irq_find_mapping(data->irq, c);
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irq_dispose_mapping(irq);
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}
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irq_domain_remove(data->irq);
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}
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i2c_mux_del_adapters(muxc);
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}
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/*
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* I2C init/probing/exit functions
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*/
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static int pca954x_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct i2c_adapter *adap = client->adapter;
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struct device *dev = &client->dev;
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struct device_node *np = dev->of_node;
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bool idle_disconnect_dt;
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struct gpio_desc *gpio;
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struct i2c_mux_core *muxc;
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struct pca954x *data;
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int num;
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int ret;
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if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
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return -ENODEV;
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muxc = i2c_mux_alloc(adap, dev, PCA954X_MAX_NCHANS, sizeof(*data), 0,
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pca954x_select_chan, pca954x_deselect_mux);
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if (!muxc)
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return -ENOMEM;
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data = i2c_mux_priv(muxc);
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i2c_set_clientdata(client, muxc);
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data->client = client;
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/* Reset the mux if a reset GPIO is specified. */
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gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
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if (IS_ERR(gpio))
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return PTR_ERR(gpio);
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if (gpio) {
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udelay(1);
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gpiod_set_value_cansleep(gpio, 0);
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/* Give the chip some time to recover. */
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udelay(1);
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}
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data->chip = of_device_get_match_data(dev);
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if (!data->chip)
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data->chip = &chips[id->driver_data];
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if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) {
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struct i2c_device_identity id;
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ret = i2c_get_device_id(client, &id);
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if (ret && ret != -EOPNOTSUPP)
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return ret;
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if (!ret &&
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(id.manufacturer_id != data->chip->id.manufacturer_id ||
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id.part_id != data->chip->id.part_id)) {
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dev_warn(dev, "unexpected device id %03x-%03x-%x\n",
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id.manufacturer_id, id.part_id,
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id.die_revision);
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return -ENODEV;
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}
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}
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/* Write the mux register at addr to verify
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* that the mux is in fact present. This also
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* initializes the mux to disconnected state.
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*/
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if (i2c_smbus_write_byte(client, 0) < 0) {
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dev_warn(dev, "probe failed\n");
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return -ENODEV;
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}
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data->last_chan = 0; /* force the first selection */
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data->idle_state = MUX_IDLE_AS_IS;
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idle_disconnect_dt = np &&
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of_property_read_bool(np, "i2c-mux-idle-disconnect");
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if (idle_disconnect_dt)
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data->idle_state = MUX_IDLE_DISCONNECT;
|
|
|
|
ret = pca954x_irq_setup(muxc);
|
|
if (ret)
|
|
goto fail_cleanup;
|
|
|
|
/* Now create an adapter for each channel */
|
|
for (num = 0; num < data->chip->nchans; num++) {
|
|
ret = i2c_mux_add_adapter(muxc, 0, num, 0);
|
|
if (ret)
|
|
goto fail_cleanup;
|
|
}
|
|
|
|
if (data->irq) {
|
|
ret = devm_request_threaded_irq(dev, data->client->irq,
|
|
NULL, pca954x_irq_handler,
|
|
IRQF_ONESHOT | IRQF_SHARED,
|
|
"pca954x", data);
|
|
if (ret)
|
|
goto fail_cleanup;
|
|
}
|
|
|
|
/*
|
|
* The attr probably isn't going to be needed in most cases,
|
|
* so don't fail completely on error.
|
|
*/
|
|
device_create_file(dev, &dev_attr_idle_state);
|
|
|
|
dev_info(dev, "registered %d multiplexed busses for I2C %s %s\n",
|
|
num, data->chip->muxtype == pca954x_ismux
|
|
? "mux" : "switch", client->name);
|
|
|
|
return 0;
|
|
|
|
fail_cleanup:
|
|
pca954x_cleanup(muxc);
|
|
return ret;
|
|
}
|
|
|
|
static int pca954x_remove(struct i2c_client *client)
|
|
{
|
|
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
|
|
|
|
pca954x_cleanup(muxc);
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PM_SLEEP
|
|
static int pca954x_resume(struct device *dev)
|
|
{
|
|
struct i2c_client *client = to_i2c_client(dev);
|
|
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
|
|
struct pca954x *data = i2c_mux_priv(muxc);
|
|
|
|
data->last_chan = 0;
|
|
return i2c_smbus_write_byte(client, 0);
|
|
}
|
|
#endif
|
|
|
|
static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
|
|
|
|
static struct i2c_driver pca954x_driver = {
|
|
.driver = {
|
|
.name = "pca954x",
|
|
.pm = &pca954x_pm,
|
|
.of_match_table = of_match_ptr(pca954x_of_match),
|
|
},
|
|
.probe = pca954x_probe,
|
|
.remove = pca954x_remove,
|
|
.id_table = pca954x_id,
|
|
};
|
|
|
|
module_i2c_driver(pca954x_driver);
|
|
|
|
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
|
|
MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
|
|
MODULE_LICENSE("GPL v2");
|