drivers/mux/adg792a.c

   1 /*
   2  * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux
   3  *
   4  * Copyright (C) 2017 Axentia Technologies AB
   5  *
   6  * Author: Peter Rosin <peda@axentia.se>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/i2c.h>
  15 #include <linux/module.h>
  16 #include <linux/mux/driver.h>
  17 #include <linux/property.h>
  18
  19 #define ADG792A_LDSW            BIT(0)
  20 #define ADG792A_RESETB          BIT(1)
  21 #define ADG792A_DISABLE(mux)    (0x50 | (mux))
  22 #define ADG792A_DISABLE_ALL     (0x5f)
  23 #define ADG792A_MUX(mux, state) (0xc0 | (((mux) + 1) << 2) | (state))
  24 #define ADG792A_MUX_ALL(state)  (0xc0 | (state))
  25
  26 static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset)
  27 {
  28         u8 data = ADG792A_RESETB | ADG792A_LDSW;
  29
  30         /* ADG792A_RESETB is active low, the chip resets when it is zero. */
  31         if (reset)
  32                 data &= ~ADG792A_RESETB;
  33
  34         return i2c_smbus_write_byte_data(i2c, cmd, data);
  35 }
  36
  37 static int adg792a_set(struct mux_control *mux, int state)
  38 {
  39         struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent);
  40         u8 cmd;
  41
  42         if (mux->chip->controllers == 1) {
  43                 /* parallel mux controller operation */
  44                 if (state == MUX_IDLE_DISCONNECT)
  45                         cmd = ADG792A_DISABLE_ALL;
  46                 else
  47                         cmd = ADG792A_MUX_ALL(state);
  48         } else {
  49                 unsigned int controller = mux_control_get_index(mux);
  50
  51                 if (state == MUX_IDLE_DISCONNECT)
  52                         cmd = ADG792A_DISABLE(controller);
  53                 else
  54                         cmd = ADG792A_MUX(controller, state);
  55         }
  56
  57         return adg792a_write_cmd(i2c, cmd, 0);
  58 }
  59
  60 static const struct mux_control_ops adg792a_ops = {
  61         .set = adg792a_set,
  62 };
  63
  64 static int adg792a_probe(struct i2c_client *i2c,
  65                          const struct i2c_device_id *id)
  66 {
  67         struct device *dev = &i2c->dev;
  68         struct mux_chip *mux_chip;
  69         s32 idle_state[3];
  70         u32 cells;
  71         int ret;
  72         int i;
  73
  74         if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  75                 return -ENODEV;
  76
  77         ret = device_property_read_u32(dev, "#mux-control-cells", &cells);
  78         if (ret < 0)
  79                 return ret;
  80         if (cells >= 2)
  81                 return -EINVAL;
  82
  83         mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0);
  84         if (IS_ERR(mux_chip))
  85                 return PTR_ERR(mux_chip);
  86
  87         mux_chip->ops = &adg792a_ops;
  88
  89         ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1);
  90         if (ret < 0)
  91                 return ret;
  92
  93         ret = device_property_read_u32_array(dev, "idle-state",
  94                                              (u32 *)idle_state,
  95                                              mux_chip->controllers);
  96         if (ret < 0) {
  97                 idle_state[0] = MUX_IDLE_AS_IS;
  98                 idle_state[1] = MUX_IDLE_AS_IS;
  99                 idle_state[2] = MUX_IDLE_AS_IS;
 100         }
 101
 102         for (i = 0; i < mux_chip->controllers; ++i) {
 103                 struct mux_control *mux = &mux_chip->mux[i];
 104
 105                 mux->states = 4;
 106
 107                 switch (idle_state[i]) {
 108                 case MUX_IDLE_DISCONNECT:
 109                 case MUX_IDLE_AS_IS:
 110                 case 0 ... 4:
 111                         mux->idle_state = idle_state[i];
 112                         break;
 113                 default:
 114                         dev_err(dev, "invalid idle-state %d\n", idle_state[i]);
 115                         return -EINVAL;
 116                 }
 117         }
 118
 119         ret = devm_mux_chip_register(dev, mux_chip);
 120         if (ret < 0)
 121                 return ret;
 122
 123         if (cells)
 124                 dev_info(dev, "3x single pole quadruple throw muxes registered\n");
 125         else
 126                 dev_info(dev, "triple pole quadruple throw mux registered\n");
 127
 128         return 0;
 129 }
 130
 131 static const struct i2c_device_id adg792a_id[] = {
 132         { .name = "adg792a", },
 133         { .name = "adg792g", },
 134         { }
 135 };
 136 MODULE_DEVICE_TABLE(i2c, adg792a_id);
 137
 138 static const struct of_device_id adg792a_of_match[] = {
 139         { .compatible = "adi,adg792a", },
 140         { .compatible = "adi,adg792g", },
 141         { }
 142 };
 143 MODULE_DEVICE_TABLE(of, adg792a_of_match);
 144
 145 static struct i2c_driver adg792a_driver = {
 146         .driver         = {
 147                 .name           = "adg792a",
 148                 .of_match_table = of_match_ptr(adg792a_of_match),
 149         },
 150         .probe          = adg792a_probe,
 151         .id_table       = adg792a_id,
 152 };
 153 module_i2c_driver(adg792a_driver);
 154
 155 MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver");
 156 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
 157 MODULE_LICENSE("GPL v2");