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
  20 enum adgs1408_chip_id {
  21         ADGS1408 = 1,
  22         ADGS1409,
  23 };
  24
  25 static 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
  36 static 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
  49 static const struct mux_control_ops adgs1408_ops = {
  50         .set = adgs1408_set,
  51 };
  52
  53 static 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
 105 static const struct spi_device_id adgs1408_spi_id[] = {
 106         { "adgs1408", ADGS1408 },
 107         { "adgs1409", ADGS1409 },
 108         { }
 109 };
 110 MODULE_DEVICE_TABLE(spi, adgs1408_spi_id);
 111
 112 static const struct of_device_id adgs1408_of_match[] = {
 113         { .compatible = "adi,adgs1408", .data = (void *)ADGS1408, },
 114         { .compatible = "adi,adgs1409", .data = (void *)ADGS1409, },
 115         { }
 116 };
 117 MODULE_DEVICE_TABLE(of, adgs1408_of_match);
 118
 119 static 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 };
 127 module_spi_driver(adgs1408_driver);
 128
 129 MODULE_AUTHOR("Mircea Caprioru <mircea.caprioru@analog.com>");
 130 MODULE_DESCRIPTION("Analog Devices ADGS1408 MUX driver");
 131 MODULE_LICENSE("GPL");