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_cmd(struct cros_ec_device *ec, u32 version, u32 command,
  26                        void *outdata, u32 outsize, void *indata, u32 insize)
  27 {
  28         struct cros_ec_command *msg;
  29         int ret;
  30
  31         msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);
  32         if (!msg)
  33                 return -ENOMEM;
  34
  35         msg->version = version;
  36         msg->command = command;
  37         msg->outsize = outsize;
  38         msg->insize = insize;
  39
  40         if (outdata && outsize > 0)
  41                 memcpy(msg->data, outdata, outsize);
  42
  43         ret = cros_ec_cmd_xfer_status(ec, msg);
  44         if (ret < 0)
  45                 goto cleanup;
  46
  47         if (insize)
  48                 memcpy(indata, msg->data, insize);
  49
  50 cleanup:
  51         kfree(msg);
  52         return ret;
  53 }
  54
  55 static int cros_ec_regulator_enable(struct regulator_dev *dev)
  56 {
  57         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  58         struct ec_params_regulator_enable cmd = {
  59                 .index = data->index,
  60                 .enable = 1,
  61         };
  62
  63         return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_ENABLE, &cmd,
  64                           sizeof(cmd), NULL, 0);
  65 }
  66
  67 static int cros_ec_regulator_disable(struct regulator_dev *dev)
  68 {
  69         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  70         struct ec_params_regulator_enable cmd = {
  71                 .index = data->index,
  72                 .enable = 0,
  73         };
  74
  75         return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_ENABLE, &cmd,
  76                           sizeof(cmd), NULL, 0);
  77 }
  78
  79 static int cros_ec_regulator_is_enabled(struct regulator_dev *dev)
  80 {
  81         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  82         struct ec_params_regulator_is_enabled cmd = {
  83                 .index = data->index,
  84         };
  85         struct ec_response_regulator_is_enabled resp;
  86         int ret;
  87
  88         ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_IS_ENABLED, &cmd,
  89                           sizeof(cmd), &resp, sizeof(resp));
  90         if (ret < 0)
  91                 return ret;
  92         return resp.enabled;
  93 }
  94
  95 static int cros_ec_regulator_list_voltage(struct regulator_dev *dev,
  96                                           unsigned int selector)
  97 {
  98         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
  99
 100         if (selector >= data->num_voltages)
 101                 return -EINVAL;
 102
 103         return data->voltages_mV[selector] * 1000;
 104 }
 105
 106 static int cros_ec_regulator_get_voltage(struct regulator_dev *dev)
 107 {
 108         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
 109         struct ec_params_regulator_get_voltage cmd = {
 110                 .index = data->index,
 111         };
 112         struct ec_response_regulator_get_voltage resp;
 113         int ret;
 114
 115         ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_GET_VOLTAGE, &cmd,
 116                           sizeof(cmd), &resp, sizeof(resp));
 117         if (ret < 0)
 118                 return ret;
 119         return resp.voltage_mv * 1000;
 120 }
 121
 122 static int cros_ec_regulator_set_voltage(struct regulator_dev *dev, int min_uV,
 123                                          int max_uV, unsigned int *selector)
 124 {
 125         struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
 126         int min_mV = DIV_ROUND_UP(min_uV, 1000);
 127         int max_mV = max_uV / 1000;
 128         struct ec_params_regulator_set_voltage cmd = {
 129                 .index = data->index,
 130                 .min_mv = min_mV,
 131                 .max_mv = max_mV,
 132         };
 133
 134         /*
 135          * This can happen when the given range [min_uV, max_uV] doesn't
 136          * contain any voltage that can be represented exactly in mV.
 137          */
 138         if (min_mV > max_mV)
 139                 return -EINVAL;
 140
 141         return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_SET_VOLTAGE, &cmd,
 142                            sizeof(cmd), NULL, 0);
 143 }
 144
 145 static const struct regulator_ops cros_ec_regulator_voltage_ops = {
 146         .enable = cros_ec_regulator_enable,
 147         .disable = cros_ec_regulator_disable,
 148         .is_enabled = cros_ec_regulator_is_enabled,
 149         .list_voltage = cros_ec_regulator_list_voltage,
 150         .get_voltage = cros_ec_regulator_get_voltage,
 151         .set_voltage = cros_ec_regulator_set_voltage,
 152 };
 153
 154 static int cros_ec_regulator_init_info(struct device *dev,
 155                                        struct cros_ec_regulator_data *data)
 156 {
 157         struct ec_params_regulator_get_info cmd = {
 158                 .index = data->index,
 159         };
 160         struct ec_response_regulator_get_info resp;
 161         int ret;
 162
 163         ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_GET_INFO, &cmd,
 164                            sizeof(cmd), &resp, sizeof(resp));
 165         if (ret < 0)
 166                 return ret;
 167
 168         data->num_voltages =
 169                 min_t(u16, ARRAY_SIZE(resp.voltages_mv), resp.num_voltages);
 170         data->voltages_mV =
 171                 devm_kmemdup(dev, resp.voltages_mv,
 172                              sizeof(u16) * data->num_voltages, GFP_KERNEL);
 173         if (!data->voltages_mV)
 174                 return -ENOMEM;
 175
 176         data->desc.n_voltages = data->num_voltages;
 177
 178         /* Make sure the returned name is always a valid string */
 179         resp.name[ARRAY_SIZE(resp.name) - 1] = '\0';
 180         data->desc.name = devm_kstrdup(dev, resp.name, GFP_KERNEL);
 181         if (!data->desc.name)
 182                 return -ENOMEM;
 183
 184         return 0;
 185 }
 186
 187 static int cros_ec_regulator_probe(struct platform_device *pdev)
 188 {
 189         struct device *dev = &pdev->dev;
 190         struct device_node *np = dev->of_node;
 191         struct cros_ec_regulator_data *drvdata;
 192         struct regulator_init_data *init_data;
 193         struct regulator_config cfg = {};
 194         struct regulator_desc *desc;
 195         int ret;
 196
 197         drvdata = devm_kzalloc(
 198                 &pdev->dev, sizeof(struct cros_ec_regulator_data), GFP_KERNEL);
 199         if (!drvdata)
 200                 return -ENOMEM;
 201
 202         drvdata->ec_dev = dev_get_drvdata(dev->parent);
 203         desc = &drvdata->desc;
 204
 205         init_data = of_get_regulator_init_data(dev, np, desc);
 206         if (!init_data)
 207                 return -EINVAL;
 208
 209         ret = of_property_read_u32(np, "reg", &drvdata->index);
 210         if (ret < 0)
 211                 return ret;
 212
 213         desc->owner = THIS_MODULE;
 214         desc->type = REGULATOR_VOLTAGE;
 215         desc->ops = &cros_ec_regulator_voltage_ops;
 216
 217         ret = cros_ec_regulator_init_info(dev, drvdata);
 218         if (ret < 0)
 219                 return ret;
 220
 221         cfg.dev = &pdev->dev;
 222         cfg.init_data = init_data;
 223         cfg.driver_data = drvdata;
 224         cfg.of_node = np;
 225
 226         drvdata->dev = devm_regulator_register(dev, &drvdata->desc, &cfg);
 227         if (IS_ERR(drvdata->dev)) {
 228                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 229                 return PTR_ERR(drvdata->dev);
 230         }
 231
 232         platform_set_drvdata(pdev, drvdata);
 233
 234         return 0;
 235 }
 236
 237 static const struct of_device_id regulator_cros_ec_of_match[] = {
 238         { .compatible = "google,cros-ec-regulator", },
 239         {}
 240 };
 241 MODULE_DEVICE_TABLE(of, regulator_cros_ec_of_match);
 242
 243 static struct platform_driver cros_ec_regulator_driver = {
 244         .probe          = cros_ec_regulator_probe,
 245         .driver         = {
 246                 .name           = "cros-ec-regulator",
 247                 .of_match_table = regulator_cros_ec_of_match,
 248         },
 249 };
 250
 251 module_platform_driver(cros_ec_regulator_driver);
 252
 253 MODULE_LICENSE("GPL v2");
 254 MODULE_DESCRIPTION("ChromeOS EC controlled regulator");
 255 MODULE_AUTHOR("Pi-Hsun Shih <pihsun@chromium.org>");