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 <[email protected]>
   6 // Copyright (c) 2017-2018 Icenowy Zheng <[email protected]>
   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 struct sy8106a {
  26         struct regulator_dev *rdev;
  27         struct regmap *regmap;
  28         u32 fixed_voltage;
  29 };
  30
  31 static const struct regmap_config sy8106a_regmap_config = {
  32         .reg_bits = 8,
  33         .val_bits = 8,
  34 };
  35
  36 static const struct regulator_ops sy8106a_ops = {
  37         .set_voltage_sel = regulator_set_voltage_sel_regmap,
  38         .set_voltage_time_sel = regulator_set_voltage_time_sel,
  39         .get_voltage_sel = regulator_get_voltage_sel_regmap,
  40         .list_voltage = regulator_list_voltage_linear,
  41         /* Enabling/disabling the regulator is not yet implemented */
  42 };
  43
  44 /* Default limits measured in millivolts */
  45 #define SY8106A_MIN_MV          680
  46 #define SY8106A_MAX_MV          1950
  47 #define SY8106A_STEP_MV         10
  48
  49 static const struct regulator_desc sy8106a_reg = {
  50         .name = "SY8106A",
  51         .id = 0,
  52         .ops = &sy8106a_ops,
  53         .type = REGULATOR_VOLTAGE,
  54         .n_voltages = ((SY8106A_MAX_MV - SY8106A_MIN_MV) / SY8106A_STEP_MV) + 1,
  55         .min_uV = (SY8106A_MIN_MV * 1000),
  56         .uV_step = (SY8106A_STEP_MV * 1000),
  57         .vsel_reg = SY8106A_REG_VOUT1_SEL,
  58         .vsel_mask = SY8106A_REG_VOUT1_SEL_MASK,
  59         /*
  60          * This ramp_delay is a conservative default value which works on
  61          * H3/H5 boards VDD-CPUX situations.
  62          */
  63         .ramp_delay = 200,
  64         .owner = THIS_MODULE,
  65 };
  66
  67 /*
  68  * I2C driver interface functions
  69  */
  70 static int sy8106a_i2c_probe(struct i2c_client *i2c,
  71                             const struct i2c_device_id *id)
  72 {
  73         struct sy8106a *chip;
  74         struct device *dev = &i2c->dev;
  75         struct regulator_dev *rdev = NULL;
  76         struct regulator_config config = { };
  77         unsigned int reg, vsel;
  78         int error;
  79
  80         chip = devm_kzalloc(&i2c->dev, sizeof(struct sy8106a), GFP_KERNEL);
  81         if (!chip)
  82                 return -ENOMEM;
  83
  84         error = of_property_read_u32(dev->of_node, "silergy,fixed-microvolt",
  85                                      &chip->fixed_voltage);
  86         if (error)
  87                 return error;
  88
  89         if (chip->fixed_voltage < SY8106A_MIN_MV * 1000 ||
  90             chip->fixed_voltage > SY8106A_MAX_MV * 1000)
  91                 return -EINVAL;
  92
  93         chip->regmap = devm_regmap_init_i2c(i2c, &sy8106a_regmap_config);
  94         if (IS_ERR(chip->regmap)) {
  95                 error = PTR_ERR(chip->regmap);
  96                 dev_err(dev, "Failed to allocate register map: %d\n", error);
  97                 return error;
  98         }
  99
 100         config.dev = &i2c->dev;
 101         config.regmap = chip->regmap;
 102         config.driver_data = chip;
 103
 104         config.of_node = dev->of_node;
 105         config.init_data = of_get_regulator_init_data(dev, dev->of_node,
 106                                                       &sy8106a_reg);
 107
 108         if (!config.init_data)
 109                 return -ENOMEM;
 110
 111         /* Ensure GO_BIT is enabled when probing */
 112         error = regmap_read(chip->regmap, SY8106A_REG_VOUT1_SEL, &reg);
 113         if (error)
 114                 return error;
 115
 116         if (!(reg & SY8106A_GO_BIT)) {
 117                 vsel = (chip->fixed_voltage / 1000 - SY8106A_MIN_MV) /
 118                        SY8106A_STEP_MV;
 119
 120                 error = regmap_write(chip->regmap, SY8106A_REG_VOUT1_SEL,
 121                                      vsel | SY8106A_GO_BIT);
 122                 if (error)
 123                         return error;
 124         }
 125
 126         /* Probe regulator */
 127         rdev = devm_regulator_register(&i2c->dev, &sy8106a_reg, &config);
 128         if (IS_ERR(rdev)) {
 129                 error = PTR_ERR(rdev);
 130                 dev_err(&i2c->dev, "Failed to register SY8106A regulator: %d\n", error);
 131                 return error;
 132         }
 133
 134         chip->rdev = rdev;
 135
 136         i2c_set_clientdata(i2c, chip);
 137
 138         return 0;
 139 }
 140
 141 static const struct of_device_id sy8106a_i2c_of_match[] = {
 142         { .compatible = "silergy,sy8106a" },
 143         { },
 144 };
 145 MODULE_DEVICE_TABLE(of, sy8106a_i2c_of_match);
 146
 147 static const struct i2c_device_id sy8106a_i2c_id[] = {
 148         { "sy8106a", 0 },
 149         { },
 150 };
 151 MODULE_DEVICE_TABLE(i2c, sy8106a_i2c_id);
 152
 153 static struct i2c_driver sy8106a_regulator_driver = {
 154         .driver = {
 155                 .name = "sy8106a",
 156                 .of_match_table = of_match_ptr(sy8106a_i2c_of_match),
 157         },
 158         .probe = sy8106a_i2c_probe,
 159         .id_table = sy8106a_i2c_id,
 160 };
 161
 162 module_i2c_driver(sy8106a_regulator_driver);
 163
 164 MODULE_AUTHOR("Ondřej Jirman <[email protected]>");
 165 MODULE_AUTHOR("Icenowy Zheng <[email protected]>");
 166 MODULE_DESCRIPTION("Regulator device driver for Silergy SY8106A");
 167 MODULE_LICENSE("GPL");