root/drivers/mux/adg792a.c

DEFINITIONS

1. adg792a_write_cmd
2. adg792a_set
3. adg792a_probe

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux
   4  *
   5  * Copyright (C) 2017 Axentia Technologies AB
   6  *
   7  * Author: Peter Rosin <peda@axentia.se>
   8  */
   9 
  10 #include <linux/err.h>
  11 #include <linux/i2c.h>
  12 #include <linux/module.h>
  13 #include <linux/mux/driver.h>
  14 #include <linux/property.h>
  15 
  16 #define ADG792A_LDSW            BIT(0)
  17 #define ADG792A_RESETB          BIT(1)
  18 #define ADG792A_DISABLE(mux)    (0x50 | (mux))
  19 #define ADG792A_DISABLE_ALL     (0x5f)
  20 #define ADG792A_MUX(mux, state) (0xc0 | (((mux) + 1) << 2) | (state))
  21 #define ADG792A_MUX_ALL(state)  (0xc0 | (state))
  22 
  23 static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset)
  24 {
  25         u8 data = ADG792A_RESETB | ADG792A_LDSW;
  26 
  27         /* ADG792A_RESETB is active low, the chip resets when it is zero. */
  28         if (reset)
  29                 data &= ~ADG792A_RESETB;
  30 
  31         return i2c_smbus_write_byte_data(i2c, cmd, data);
  32 }
  33 
  34 static int adg792a_set(struct mux_control *mux, int state)
  35 {
  36         struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent);
  37         u8 cmd;
  38 
  39         if (mux->chip->controllers == 1) {
  40                 /* parallel mux controller operation */
  41                 if (state == MUX_IDLE_DISCONNECT)
  42                         cmd = ADG792A_DISABLE_ALL;
  43                 else
  44                         cmd = ADG792A_MUX_ALL(state);
  45         } else {
  46                 unsigned int controller = mux_control_get_index(mux);
  47 
  48                 if (state == MUX_IDLE_DISCONNECT)
  49                         cmd = ADG792A_DISABLE(controller);
  50                 else
  51                         cmd = ADG792A_MUX(controller, state);
  52         }
  53 
  54         return adg792a_write_cmd(i2c, cmd, 0);
  55 }
  56 
  57 static const struct mux_control_ops adg792a_ops = {
  58         .set = adg792a_set,
  59 };
  60 
  61 static int adg792a_probe(struct i2c_client *i2c)
  62 {
  63         struct device *dev = &i2c->dev;
  64         struct mux_chip *mux_chip;
  65         s32 idle_state[3];
  66         u32 cells;
  67         int ret;
  68         int i;
  69 
  70         if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  71                 return -ENODEV;
  72 
  73         ret = device_property_read_u32(dev, "#mux-control-cells", &cells);
  74         if (ret < 0)
  75                 return ret;
  76         if (cells >= 2)
  77                 return -EINVAL;
  78 
  79         mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0);
  80         if (IS_ERR(mux_chip))
  81                 return PTR_ERR(mux_chip);
  82 
  83         mux_chip->ops = &adg792a_ops;
  84 
  85         ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1);
  86         if (ret < 0)
  87                 return ret;
  88 
  89         ret = device_property_read_u32_array(dev, "idle-state",
  90                                              (u32 *)idle_state,
  91                                              mux_chip->controllers);
  92         if (ret < 0) {
  93                 idle_state[0] = MUX_IDLE_AS_IS;
  94                 idle_state[1] = MUX_IDLE_AS_IS;
  95                 idle_state[2] = MUX_IDLE_AS_IS;
  96         }
  97 
  98         for (i = 0; i < mux_chip->controllers; ++i) {
  99                 struct mux_control *mux = &mux_chip->mux[i];
 100 
 101                 mux->states = 4;
 102 
 103                 switch (idle_state[i]) {
 104                 case MUX_IDLE_DISCONNECT:
 105                 case MUX_IDLE_AS_IS:
 106                 case 0 ... 4:
 107                         mux->idle_state = idle_state[i];
 108                         break;
 109                 default:
 110                         dev_err(dev, "invalid idle-state %d\n", idle_state[i]);
 111                         return -EINVAL;
 112                 }
 113         }
 114 
 115         ret = devm_mux_chip_register(dev, mux_chip);
 116         if (ret < 0)
 117                 return ret;
 118 
 119         if (cells)
 120                 dev_info(dev, "3x single pole quadruple throw muxes registered\n");
 121         else
 122                 dev_info(dev, "triple pole quadruple throw mux registered\n");
 123 
 124         return 0;
 125 }
 126 
 127 static const struct i2c_device_id adg792a_id[] = {
 128         { .name = "adg792a", },
 129         { .name = "adg792g", },
 130         { }
 131 };
 132 MODULE_DEVICE_TABLE(i2c, adg792a_id);
 133 
 134 static const struct of_device_id adg792a_of_match[] = {
 135         { .compatible = "adi,adg792a", },
 136         { .compatible = "adi,adg792g", },
 137         { }
 138 };
 139 MODULE_DEVICE_TABLE(of, adg792a_of_match);
 140 
 141 static struct i2c_driver adg792a_driver = {
 142         .driver         = {
 143                 .name           = "adg792a",
 144                 .of_match_table = of_match_ptr(adg792a_of_match),
 145         },
 146         .probe_new      = adg792a_probe,
 147         .id_table       = adg792a_id,
 148 };
 149 module_i2c_driver(adg792a_driver);
 150 
 151 MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver");
 152 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
 153 MODULE_LICENSE("GPL v2");