drivers/regulator/sy8106a-regulator.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // sy8106a-regulator.c - Regulator device driver for SY8106A
   4 //
   5 // Copyright (C) 2016 Ondřej Jirman <megous@megous.com>
   6 // Copyright (c) 2017-2018 Icenowy Zheng <icenowy@aosc.io>
   7
   8 #include <linux/err.h>
   9 #include <linux/i2c.h>
  10 #include <linux/module.h>
  11 #include <linux/regmap.h>
  12 #include <linux/regulator/driver.h>
  13 #include <linux/regulator/of_regulator.h>
  14
  15 #define SY8106A_REG_VOUT1_SEL           0x01
  16 #define SY8106A_REG_VOUT_COM            0x02
  17 #define SY8106A_REG_VOUT1_SEL_MASK      0x7f
  18 #define SY8106A_DISABLE_REG             BIT(0)
  19 /*
  20  * The I2C controlled voltage will only work when this bit is set; otherwise
  21  * it will behave like a fixed regulator.
  22  */
  23 #define SY8106A_GO_BIT                  BIT(7)
  24
  25 static const struct regmap_config sy8106a_regmap_config = {
  26         .reg_bits = 8,
  27         .val_bits = 8,
  28 };
  29
  30 static const struct regulator_ops sy8106a_ops = {
  31         .set_voltage_sel = regulator_set_voltage_sel_regmap,
  32         .set_voltage_time_sel = regulator_set_voltage_time_sel,
  33         .get_voltage_sel = regulator_get_voltage_sel_regmap,
  34         .list_voltage = regulator_list_voltage_linear,
  35         /* Enabling/disabling the regulator is not yet implemented */
  36 };
  37
  38 /* Default limits measured in millivolts */
  39 #define SY8106A_MIN_MV          680
  40 #define SY8106A_MAX_MV          1950
  41 #define SY8106A_STEP_MV         10
  42
  43 static const struct regulator_desc sy8106a_reg = {
  44         .name = "SY8106A",
  45         .id = 0,
  46         .ops = &sy8106a_ops,
  47         .type = REGULATOR_VOLTAGE,
  48         .n_voltages = ((SY8106A_MAX_MV - SY8106A_MIN_MV) / SY8106A_STEP_MV) + 1,
  49         .min_uV = (SY8106A_MIN_MV * 1000),
  50         .uV_step = (SY8106A_STEP_MV * 1000),
  51         .vsel_reg = SY8106A_REG_VOUT1_SEL,
  52         .vsel_mask = SY8106A_REG_VOUT1_SEL_MASK,
  53         /*
  54          * This ramp_delay is a conservative default value which works on
  55          * H3/H5 boards VDD-CPUX situations.
  56          */
  57         .ramp_delay = 200,
  58         .owner = THIS_MODULE,
  59 };
  60
  61 /*
  62  * I2C driver interface functions
  63  */
  64 static int sy8106a_i2c_probe(struct i2c_client *i2c)
  65 {
  66         struct device *dev = &i2c->dev;
  67         struct regulator_dev *rdev;
  68         struct regulator_config config = { };
  69         struct regmap *regmap;
  70         unsigned int reg, vsel;
  71         u32 fixed_voltage;
  72         int error;
  73
  74         error = of_property_read_u32(dev->of_node, "silergy,fixed-microvolt",
  75                                      &fixed_voltage);
  76         if (error)
  77                 return error;
  78
  79         if (fixed_voltage < SY8106A_MIN_MV * 1000 ||
  80             fixed_voltage > SY8106A_MAX_MV * 1000)
  81                 return -EINVAL;
  82
  83         regmap = devm_regmap_init_i2c(i2c, &sy8106a_regmap_config);
  84         if (IS_ERR(regmap)) {
  85                 error = PTR_ERR(regmap);
  86                 dev_err(dev, "Failed to allocate register map: %d\n", error);
  87                 return error;
  88         }
  89
  90         config.dev = &i2c->dev;
  91         config.regmap = regmap;
  92
  93         config.of_node = dev->of_node;
  94         config.init_data = of_get_regulator_init_data(dev, dev->of_node,
  95                                                       &sy8106a_reg);
  96
  97         if (!config.init_data)
  98                 return -ENOMEM;
  99
 100         /* Ensure GO_BIT is enabled when probing */
 101         error = regmap_read(regmap, SY8106A_REG_VOUT1_SEL, &reg);
 102         if (error)
 103                 return error;
 104
 105         if (!(reg & SY8106A_GO_BIT)) {
 106                 vsel = (fixed_voltage / 1000 - SY8106A_MIN_MV) /
 107                        SY8106A_STEP_MV;
 108
 109                 error = regmap_write(regmap, SY8106A_REG_VOUT1_SEL,
 110                                      vsel | SY8106A_GO_BIT);
 111                 if (error)
 112                         return error;
 113         }
 114
 115         /* Probe regulator */
 116         rdev = devm_regulator_register(&i2c->dev, &sy8106a_reg, &config);
 117         if (IS_ERR(rdev)) {
 118                 error = PTR_ERR(rdev);
 119                 dev_err(&i2c->dev, "Failed to register SY8106A regulator: %d\n", error);
 120                 return error;
 121         }
 122
 123         return 0;
 124 }
 125
 126 static const struct of_device_id sy8106a_i2c_of_match[] = {
 127         { .compatible = "silergy,sy8106a" },
 128         { },
 129 };
 130 MODULE_DEVICE_TABLE(of, sy8106a_i2c_of_match);
 131
 132 static const struct i2c_device_id sy8106a_i2c_id[] = {
 133         { "sy8106a", 0 },
 134         { },
 135 };
 136 MODULE_DEVICE_TABLE(i2c, sy8106a_i2c_id);
 137
 138 static struct i2c_driver sy8106a_regulator_driver = {
 139         .driver = {
 140                 .name = "sy8106a",
 141                 .of_match_table = of_match_ptr(sy8106a_i2c_of_match),
 142         },
 143         .probe_new = sy8106a_i2c_probe,
 144         .id_table = sy8106a_i2c_id,
 145 };
 146
 147 module_i2c_driver(sy8106a_regulator_driver);
 148
 149 MODULE_AUTHOR("Ondřej Jirman <megous@megous.com>");
 150 MODULE_AUTHOR("Icenowy Zheng <icenowy@aosc.io>");
 151 MODULE_DESCRIPTION("Regulator device driver for Silergy SY8106A");
 152 MODULE_LICENSE("GPL");