drivers/regulator/cros-ec-regulator.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 //
   3 // Copyright 2020 Google LLC.
   4
   5 #include <linux/module.h>
   6 #include <linux/of.h>
   7 #include <linux/platform_data/cros_ec_proto.h>
   8 #include <linux/platform_device.h>
   9 #include <linux/regulator/driver.h>
  10 #include <linux/regulator/machine.h>
  11 #include <linux/regulator/of_regulator.h>
  12 #include <linux/slab.h>
  13
  14 struct cros_ec_regulator_data {
  15         struct regulator_desc desc;
  16         struct regulator_dev *dev;
  17         struct cros_ec_device *ec_dev;
  18
  19         u32 index;
  20
  21         u16 *voltages_mV;
  22         u16 num_voltages;
  23 };
  24
  25 static int cros_ec_regulator_enable(struct regulator_dev *dev)
  26 {
  27         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  28         struct ec_params_regulator_enable cmd = {
  29                 .index = data->index,
  30                 .enable = 1,
  31         };
  32
  33         return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_ENABLE, &cmd,
  34                            sizeof(cmd), NULL, 0);
  35 }
  36
  37 static int cros_ec_regulator_disable(struct regulator_dev *dev)
  38 {
  39         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  40         struct ec_params_regulator_enable cmd = {
  41                 .index = data->index,
  42                 .enable = 0,
  43         };
  44
  45         return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_ENABLE, &cmd,
  46                            sizeof(cmd), NULL, 0);
  47 }
  48
  49 static int cros_ec_regulator_is_enabled(struct regulator_dev *dev)
  50 {
  51         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  52         struct ec_params_regulator_is_enabled cmd = {
  53                 .index = data->index,
  54         };
  55         struct ec_response_regulator_is_enabled resp;
  56         int ret;
  57
  58         ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_IS_ENABLED, &cmd,
  59                           sizeof(cmd), &resp, sizeof(resp));
  60         if (ret < 0)
  61                 return ret;
  62         return resp.enabled;
  63 }
  64
  65 static int cros_ec_regulator_list_voltage(struct regulator_dev *dev,
  66                                           unsigned int selector)
  67 {
  68         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  69
  70         if (selector >= data->num_voltages)
  71                 return -EINVAL;
  72
  73         return data->voltages_mV[selector] * 1000;
  74 }
  75
  76 static int cros_ec_regulator_get_voltage(struct regulator_dev *dev)
  77 {
  78         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  79         struct ec_params_regulator_get_voltage cmd = {
  80                 .index = data->index,
  81         };
  82         struct ec_response_regulator_get_voltage resp;
  83         int ret;
  84
  85         ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_GET_VOLTAGE, &cmd,
  86                           sizeof(cmd), &resp, sizeof(resp));
  87         if (ret < 0)
  88                 return ret;
  89         return resp.voltage_mv * 1000;
  90 }
  91
  92 static int cros_ec_regulator_set_voltage(struct regulator_dev *dev, int min_uV,
  93                                          int max_uV, unsigned int *selector)
  94 {
  95         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  96         int min_mV = DIV_ROUND_UP(min_uV, 1000);
  97         int max_mV = max_uV / 1000;
  98         struct ec_params_regulator_set_voltage cmd = {
  99                 .index = data->index,
 100                 .min_mv = min_mV,
 101                 .max_mv = max_mV,
 102         };
 103
 104         /*
 105          * This can happen when the given range [min_uV, max_uV] doesn't
 106          * contain any voltage that can be represented exactly in mV.
 107          */
 108         if (min_mV > max_mV)
 109                 return -EINVAL;
 110
 111         return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_SET_VOLTAGE, &cmd,
 112                            sizeof(cmd), NULL, 0);
 113 }
 114
 115 static const struct regulator_ops cros_ec_regulator_voltage_ops = {
 116         .enable = cros_ec_regulator_enable,
 117         .disable = cros_ec_regulator_disable,
 118         .is_enabled = cros_ec_regulator_is_enabled,
 119         .list_voltage = cros_ec_regulator_list_voltage,
 120         .get_voltage = cros_ec_regulator_get_voltage,
 121         .set_voltage = cros_ec_regulator_set_voltage,
 122 };
 123
 124 static int cros_ec_regulator_init_info(struct device *dev,
 125                                        struct cros_ec_regulator_data *data)
 126 {
 127         struct ec_params_regulator_get_info cmd = {
 128                 .index = data->index,
 129         };
 130         struct ec_response_regulator_get_info resp;
 131         int ret;
 132
 133         ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_GET_INFO, &cmd,
 134                           sizeof(cmd), &resp, sizeof(resp));
 135         if (ret < 0)
 136                 return ret;
 137
 138         data->num_voltages =
 139                 min_t(u16, ARRAY_SIZE(resp.voltages_mv), resp.num_voltages);
 140         data->voltages_mV =
 141                 devm_kmemdup(dev, resp.voltages_mv,
 142                              sizeof(u16) * data->num_voltages, GFP_KERNEL);
 143         if (!data->voltages_mV)
 144                 return -ENOMEM;
 145
 146         data->desc.n_voltages = data->num_voltages;
 147
 148         /* Make sure the returned name is always a valid string */
 149         resp.name[ARRAY_SIZE(resp.name) - 1] = '\0';
 150         data->desc.name = devm_kstrdup(dev, resp.name, GFP_KERNEL);
 151         if (!data->desc.name)
 152                 return -ENOMEM;
 153
 154         return 0;
 155 }
 156
 157 static int cros_ec_regulator_probe(struct platform_device *pdev)
 158 {
 159         struct device *dev = &pdev->dev;
 160         struct device_node *np = dev->of_node;
 161         struct cros_ec_regulator_data *drvdata;
 162         struct regulator_init_data *init_data;
 163         struct regulator_config cfg = {};
 164         struct regulator_desc *desc;
 165         int ret;
 166
 167         drvdata = devm_kzalloc(
 168                 &pdev->dev, sizeof(struct cros_ec_regulator_data), GFP_KERNEL);
 169         if (!drvdata)
 170                 return -ENOMEM;
 171
 172         drvdata->ec_dev = dev_get_drvdata(dev->parent);
 173         desc = &drvdata->desc;
 174
 175         init_data = of_get_regulator_init_data(dev, np, desc);
 176         if (!init_data)
 177                 return -EINVAL;
 178
 179         ret = of_property_read_u32(np, "reg", &drvdata->index);
 180         if (ret < 0)
 181                 return ret;
 182
 183         desc->owner = THIS_MODULE;
 184         desc->type = REGULATOR_VOLTAGE;
 185         desc->ops = &cros_ec_regulator_voltage_ops;
 186
 187         ret = cros_ec_regulator_init_info(dev, drvdata);
 188         if (ret < 0)
 189                 return ret;
 190
 191         cfg.dev = &pdev->dev;
 192         cfg.init_data = init_data;
 193         cfg.driver_data = drvdata;
 194         cfg.of_node = np;
 195
 196         drvdata->dev = devm_regulator_register(dev, &drvdata->desc, &cfg);
 197         if (IS_ERR(drvdata->dev)) {
 198                 ret = PTR_ERR(drvdata->dev);
 199                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 200                 return ret;
 201         }
 202
 203         platform_set_drvdata(pdev, drvdata);
 204
 205         return 0;
 206 }
 207
 208 static const struct of_device_id regulator_cros_ec_of_match[] = {
 209         { .compatible = "google,cros-ec-regulator", },
 210         {}
 211 };
 212 MODULE_DEVICE_TABLE(of, regulator_cros_ec_of_match);
 213
 214 static struct platform_driver cros_ec_regulator_driver = {
 215         .probe          = cros_ec_regulator_probe,
 216         .driver         = {
 217                 .name           = "cros-ec-regulator",
 218                 .of_match_table = regulator_cros_ec_of_match,
 219         },
 220 };
 221
 222 module_platform_driver(cros_ec_regulator_driver);
 223
 224 MODULE_LICENSE("GPL v2");
 225 MODULE_DESCRIPTION("ChromeOS EC controlled regulator");
 226 MODULE_AUTHOR("Pi-Hsun Shih <pihsun@chromium.org>");