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567 lines
14 KiB
567 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* I2C multiplexer |
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* |
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* Copyright (c) 2008-2009 Rodolfo Giometti <[email protected]> |
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* Copyright (c) 2008-2009 Eurotech S.p.A. <[email protected]> |
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* |
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* This module supports the PCA954x and PCA984x 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 <[email protected]> |
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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 <[email protected]> |
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* and |
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* pca9540.c from Jean Delvare <[email protected]>. |
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*/ |
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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/pm.h> |
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#include <linux/property.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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|
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#define PCA954X_MAX_NCHANS 8 |
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|
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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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|
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struct pca954x { |
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const struct chip_desc *chip; |
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|
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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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s32 idle_state; |
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struct i2c_client *client; |
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|
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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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|
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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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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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|
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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 u8 pca954x_regval(struct pca954x *data, u8 chan) |
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{ |
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/* We make switches look like muxes, not sure how to be smarter. */ |
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if (data->chip->muxtype == pca954x_ismux) |
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return chan | data->chip->enable; |
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else |
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return 1 << chan; |
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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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u8 regval; |
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int ret = 0; |
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regval = pca954x_regval(data, 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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s32 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 long pending; |
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int ret, i; |
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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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pending = (ret >> PCA954X_IRQ_OFFSET) & (BIT(data->chip->nchans) - 1); |
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for_each_set_bit(i, &pending, data->chip->nchans) |
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handle_nested_irq(irq_linear_revmap(data->irq, i)); |
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return IRQ_RETVAL(pending); |
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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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int c, irq; |
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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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static int pca954x_init(struct i2c_client *client, struct pca954x *data) |
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{ |
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int ret; |
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if (data->idle_state >= 0) |
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data->last_chan = pca954x_regval(data, data->idle_state); |
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else |
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data->last_chan = 0; /* Disconnect multiplexer */ |
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ret = i2c_smbus_write_byte(client, data->last_chan); |
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if (ret < 0) |
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data->last_chan = 0; |
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return ret; |
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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 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 = 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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|
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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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|
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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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data->idle_state = MUX_IDLE_AS_IS; |
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if (device_property_read_u32(dev, "idle-state", &data->idle_state)) { |
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if (device_property_read_bool(dev, "i2c-mux-idle-disconnect")) |
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data->idle_state = MUX_IDLE_DISCONNECT; |
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} |
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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 a channel |
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* or disconnected state. |
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*/ |
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ret = pca954x_init(client, data); |
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if (ret < 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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|
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ret = pca954x_irq_setup(muxc); |
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if (ret) |
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goto fail_cleanup; |
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|
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/* Now create an adapter for each channel */ |
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for (num = 0; num < data->chip->nchans; num++) { |
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ret = i2c_mux_add_adapter(muxc, 0, num, 0); |
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if (ret) |
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goto fail_cleanup; |
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} |
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|
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if (data->irq) { |
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ret = devm_request_threaded_irq(dev, data->client->irq, |
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NULL, pca954x_irq_handler, |
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IRQF_ONESHOT | IRQF_SHARED, |
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"pca954x", data); |
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if (ret) |
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goto fail_cleanup; |
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} |
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|
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/* |
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* The attr probably isn't going to be needed in most cases, |
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* so don't fail completely on error. |
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*/ |
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device_create_file(dev, &dev_attr_idle_state); |
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|
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dev_info(dev, "registered %d multiplexed busses for I2C %s %s\n", |
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num, data->chip->muxtype == pca954x_ismux |
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? "mux" : "switch", client->name); |
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|
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return 0; |
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|
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fail_cleanup: |
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pca954x_cleanup(muxc); |
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return ret; |
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} |
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|
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static int pca954x_remove(struct i2c_client *client) |
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{ |
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struct i2c_mux_core *muxc = i2c_get_clientdata(client); |
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|
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device_remove_file(&client->dev, &dev_attr_idle_state); |
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|
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pca954x_cleanup(muxc); |
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return 0; |
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} |
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|
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#ifdef CONFIG_PM_SLEEP |
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static int pca954x_resume(struct device *dev) |
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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 ret; |
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|
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ret = pca954x_init(client, data); |
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if (ret < 0) |
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dev_err(&client->dev, "failed to verify mux presence\n"); |
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|
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return ret; |
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} |
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#endif |
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|
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static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume); |
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|
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static struct i2c_driver pca954x_driver = { |
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.driver = { |
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.name = "pca954x", |
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.pm = &pca954x_pm, |
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.of_match_table = pca954x_of_match, |
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}, |
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.probe = pca954x_probe, |
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.remove = pca954x_remove, |
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.id_table = pca954x_id, |
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}; |
|
|
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module_i2c_driver(pca954x_driver); |
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|
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MODULE_AUTHOR("Rodolfo Giometti <[email protected]>"); |
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MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); |
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MODULE_LICENSE("GPL v2");
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