LXR linux/drivers/mux/adgs1408.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * ADGS1408/ADGS1409 SPI MUX driver
   4 *
   5 * Copyright 2018 Analog Devices Inc.
   6 */
   7
   8#include <linux/err.h>
   9#include <linux/mod_devicetable.h>
  10#include <linux/module.h>
  11#include <linux/mux/driver.h>
  12#include <linux/property.h>
  13#include <linux/spi/spi.h>
  14
  15#define ADGS1408_SW_DATA       (0x01)
  16#define ADGS1408_REG_READ(reg) ((reg) | 0x80)
  17#define ADGS1408_DISABLE       (0x00)
  18#define ADGS1408_MUX(state)    (((state) << 1) | 1)
  19
  20enum adgs1408_chip_id {
  21        ADGS1408 = 1,
  22        ADGS1409,
  23};
  24
  25static int adgs1408_spi_reg_write(struct spi_device *spi,
  26                                  u8 reg_addr, u8 reg_data)
  27{
  28        u8 tx_buf[2];
  29
  30        tx_buf[0] = reg_addr;
  31        tx_buf[1] = reg_data;
  32
  33        return spi_write_then_read(spi, tx_buf, sizeof(tx_buf), NULL, 0);
  34}
  35
  36static int adgs1408_set(struct mux_control *mux, int state)
  37{
  38        struct spi_device *spi = to_spi_device(mux->chip->dev.parent);
  39        u8 reg;
  40
  41        if (state == MUX_IDLE_DISCONNECT)
  42                reg = ADGS1408_DISABLE;
  43        else
  44                reg = ADGS1408_MUX(state);
  45
  46        return adgs1408_spi_reg_write(spi, ADGS1408_SW_DATA, reg);
  47}
  48
  49static const struct mux_control_ops adgs1408_ops = {
  50        .set = adgs1408_set,
  51};
  52
  53static int adgs1408_probe(struct spi_device *spi)
  54{
  55        struct device *dev = &spi->dev;
  56        enum adgs1408_chip_id chip_id;
  57        struct mux_chip *mux_chip;
  58        struct mux_control *mux;
  59        s32 idle_state;
  60        int ret;
  61
  62        chip_id = (enum adgs1408_chip_id)device_get_match_data(dev);
  63        if (!chip_id)
  64                chip_id = spi_get_device_id(spi)->driver_data;
  65
  66        mux_chip = devm_mux_chip_alloc(dev, 1, 0);
  67        if (IS_ERR(mux_chip))
  68                return PTR_ERR(mux_chip);
  69
  70        mux_chip->ops = &adgs1408_ops;
  71
  72        ret = adgs1408_spi_reg_write(spi, ADGS1408_SW_DATA, ADGS1408_DISABLE);
  73        if (ret < 0)
  74                return ret;
  75
  76        ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
  77        if (ret < 0)
  78                idle_state = MUX_IDLE_AS_IS;
  79
  80        mux = mux_chip->mux;
  81
  82        if (chip_id == ADGS1408)
  83                mux->states = 8;
  84        else
  85                mux->states = 4;
  86
  87        switch (idle_state) {
  88        case MUX_IDLE_DISCONNECT:
  89        case MUX_IDLE_AS_IS:
  90        case 0 ... 7:
  91                /* adgs1409 supports only 4 states */
  92                if (idle_state < mux->states) {
  93                        mux->idle_state = idle_state;
  94                        break;
  95                }
  96                fallthrough;
  97        default:
  98                dev_err(dev, "invalid idle-state %d\n", idle_state);
  99                return -EINVAL;
 100        }
 101
 102        return devm_mux_chip_register(dev, mux_chip);
 103}
 104
 105static const struct spi_device_id adgs1408_spi_id[] = {
 106        { "adgs1408", ADGS1408 },
 107        { "adgs1409", ADGS1409 },
 108        { }
 109};
 110MODULE_DEVICE_TABLE(spi, adgs1408_spi_id);
 111
 112static const struct of_device_id adgs1408_of_match[] = {
 113        { .compatible = "adi,adgs1408", .data = (void *)ADGS1408, },
 114        { .compatible = "adi,adgs1409", .data = (void *)ADGS1409, },
 115        { }
 116};
 117MODULE_DEVICE_TABLE(of, adgs1408_of_match);
 118
 119static struct spi_driver adgs1408_driver = {
 120        .driver = {
 121                .name = "adgs1408",
 122                .of_match_table = adgs1408_of_match,
 123        },
 124        .probe = adgs1408_probe,
 125        .id_table = adgs1408_spi_id,
 126};
 127module_spi_driver(adgs1408_driver);
 128
 129MODULE_AUTHOR("Mircea Caprioru <mircea.caprioru@analog.com>");
 130MODULE_DESCRIPTION("Analog Devices ADGS1408 MUX driver");
 131MODULE_LICENSE("GPL");
 132