regulator: Add driver for cros-ec-regulator

Add driver for cros-ec-regulator, representing a voltage regulator that
is connected and controlled by ChromeOS EC, and is controlled by kernel
with EC host commands.

Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
Reviewed-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20200612040526.192878-4-pihsun@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 8f677f5..c398e90 100644 (file)
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -238,6 +238,16 @@ config REGULATOR_CPCAP
          Say y here for CPCAP regulator found on some Motorola phones
          and tablets such as Droid 4.
 
+config REGULATOR_CROS_EC
+       tristate "ChromeOS EC regulators"
+       depends on CROS_EC && OF
+       help
+         This driver supports voltage regulators that is connected to ChromeOS
+         EC and controlled through EC host commands.
+
+         This driver can also be built as a module. If so, the module
+         will be called cros-ec-regulator.
+
 config REGULATOR_DA903X
        tristate "Dialog Semiconductor DA9030/DA9034 regulators"
        depends on PMIC_DA903X

diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index e8f1633..46592c1 100644 (file)
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_REGULATOR_USERSPACE_CONSUMER) += userspace-consumer.o
 obj-$(CONFIG_REGULATOR_88PG86X) += 88pg86x.o
 obj-$(CONFIG_REGULATOR_88PM800) += 88pm800-regulator.o
 obj-$(CONFIG_REGULATOR_88PM8607) += 88pm8607.o
+obj-$(CONFIG_REGULATOR_CROS_EC) += cros-ec-regulator.o
 obj-$(CONFIG_REGULATOR_CPCAP) += cpcap-regulator.o
 obj-$(CONFIG_REGULATOR_AAT2870) += aat2870-regulator.o
 obj-$(CONFIG_REGULATOR_AB3100) += ab3100.o

diff --git a/drivers/regulator/cros-ec-regulator.c b/drivers/regulator/cros-ec-regulator.c
new file mode 100644 (file)
index 0000000..35f9724
--- /dev/null
+++ b/drivers/regulator/cros-ec-regulator.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright 2020 Google LLC.
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/slab.h>
+
+struct cros_ec_regulator_data {
+       struct regulator_desc desc;
+       struct regulator_dev *dev;
+       struct cros_ec_device *ec_dev;
+
+       u32 index;
+
+       u16 *voltages_mV;
+       u16 num_voltages;
+};
+
+static int cros_ec_cmd(struct cros_ec_device *ec, u32 version, u32 command,
+                      void *outdata, u32 outsize, void *indata, u32 insize)
+{
+       struct cros_ec_command *msg;
+       int ret;
+
+       msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);
+       if (!msg)
+               return -ENOMEM;
+
+       msg->version = version;
+       msg->command = command;
+       msg->outsize = outsize;
+       msg->insize = insize;
+
+       if (outdata && outsize > 0)
+               memcpy(msg->data, outdata, outsize);
+
+       ret = cros_ec_cmd_xfer_status(ec, msg);
+       if (ret < 0)
+               goto cleanup;
+
+       if (insize)
+               memcpy(indata, msg->data, insize);
+
+cleanup:
+       kfree(msg);
+       return ret;
+}
+
+static int cros_ec_regulator_enable(struct regulator_dev *dev)
+{
+       struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+       struct ec_params_regulator_enable cmd = {
+               .index = data->index,
+               .enable = 1,
+       };
+
+       return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_ENABLE, &cmd,
+                         sizeof(cmd), NULL, 0);
+}
+
+static int cros_ec_regulator_disable(struct regulator_dev *dev)
+{
+       struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+       struct ec_params_regulator_enable cmd = {
+               .index = data->index,
+               .enable = 0,
+       };
+
+       return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_ENABLE, &cmd,
+                         sizeof(cmd), NULL, 0);
+}
+
+static int cros_ec_regulator_is_enabled(struct regulator_dev *dev)
+{
+       struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+       struct ec_params_regulator_is_enabled cmd = {
+               .index = data->index,
+       };
+       struct ec_response_regulator_is_enabled resp;
+       int ret;
+
+       ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_IS_ENABLED, &cmd,
+                         sizeof(cmd), &resp, sizeof(resp));
+       if (ret < 0)
+               return ret;
+       return resp.enabled;
+}
+
+static int cros_ec_regulator_list_voltage(struct regulator_dev *dev,
+                                         unsigned int selector)
+{
+       struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+
+       if (selector >= data->num_voltages)
+               return -EINVAL;
+
+       return data->voltages_mV[selector] * 1000;
+}
+
+static int cros_ec_regulator_get_voltage(struct regulator_dev *dev)
+{
+       struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+       struct ec_params_regulator_get_voltage cmd = {
+               .index = data->index,
+       };
+       struct ec_response_regulator_get_voltage resp;
+       int ret;
+
+       ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_GET_VOLTAGE, &cmd,
+                         sizeof(cmd), &resp, sizeof(resp));
+       if (ret < 0)
+               return ret;
+       return resp.voltage_mv * 1000;
+}
+
+static int cros_ec_regulator_set_voltage(struct regulator_dev *dev, int min_uV,
+                                        int max_uV, unsigned int *selector)
+{
+       struct cros_ec_regulator_data *data = rdev_get_drvdata(dev);
+       int min_mV = DIV_ROUND_UP(min_uV, 1000);
+       int max_mV = max_uV / 1000;
+       struct ec_params_regulator_set_voltage cmd = {
+               .index = data->index,
+               .min_mv = min_mV,
+               .max_mv = max_mV,
+       };
+
+       /*
+        * This can happen when the given range [min_uV, max_uV] doesn't
+        * contain any voltage that can be represented exactly in mV.
+        */
+       if (min_mV > max_mV)
+               return -EINVAL;
+
+       return cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_SET_VOLTAGE, &cmd,
+                          sizeof(cmd), NULL, 0);
+}
+
+static struct regulator_ops cros_ec_regulator_voltage_ops = {
+       .enable = cros_ec_regulator_enable,
+       .disable = cros_ec_regulator_disable,
+       .is_enabled = cros_ec_regulator_is_enabled,
+       .list_voltage = cros_ec_regulator_list_voltage,
+       .get_voltage = cros_ec_regulator_get_voltage,
+       .set_voltage = cros_ec_regulator_set_voltage,
+};
+
+static int cros_ec_regulator_init_info(struct device *dev,
+                                      struct cros_ec_regulator_data *data)
+{
+       struct ec_params_regulator_get_info cmd = {
+               .index = data->index,
+       };
+       struct ec_response_regulator_get_info resp;
+       int ret;
+
+       ret = cros_ec_cmd(data->ec_dev, 0, EC_CMD_REGULATOR_GET_INFO, &cmd,
+                          sizeof(cmd), &resp, sizeof(resp));
+       if (ret < 0)
+               return ret;
+
+       data->num_voltages =
+               min_t(u16, ARRAY_SIZE(resp.voltages_mv), resp.num_voltages);
+       data->voltages_mV =
+               devm_kmemdup(dev, resp.voltages_mv,
+                            sizeof(u16) * data->num_voltages, GFP_KERNEL);
+       data->desc.n_voltages = data->num_voltages;
+
+       /* Make sure the returned name is always a valid string */
+       resp.name[ARRAY_SIZE(resp.name) - 1] = '\0';
+       data->desc.name = devm_kstrdup(dev, resp.name, GFP_KERNEL);
+       if (!data->desc.name)
+               return -ENOMEM;
+
+       return 0;
+}
+
+static int cros_ec_regulator_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device_node *np = dev->of_node;
+       struct cros_ec_regulator_data *drvdata;
+       struct regulator_init_data *init_data;
+       struct regulator_config cfg = {};
+       struct regulator_desc *desc;
+       int ret;
+
+       drvdata = devm_kzalloc(
+               &pdev->dev, sizeof(struct cros_ec_regulator_data), GFP_KERNEL);
+       if (!drvdata)
+               return -ENOMEM;
+
+       drvdata->ec_dev = dev_get_drvdata(dev->parent);
+       desc = &drvdata->desc;
+
+       init_data = of_get_regulator_init_data(dev, np, desc);
+       if (!init_data)
+               return -EINVAL;
+
+       ret = of_property_read_u32(np, "reg", &drvdata->index);
+       if (ret < 0)
+               return ret;
+
+       desc->owner = THIS_MODULE;
+       desc->type = REGULATOR_VOLTAGE;
+       desc->ops = &cros_ec_regulator_voltage_ops;
+
+       ret = cros_ec_regulator_init_info(dev, drvdata);
+       if (ret < 0)
+               return ret;
+
+       cfg.dev = &pdev->dev;
+       cfg.init_data = init_data;
+       cfg.driver_data = drvdata;
+       cfg.of_node = np;
+
+       drvdata->dev = devm_regulator_register(dev, &drvdata->desc, &cfg);
+       if (IS_ERR(drvdata->dev)) {
+               ret = PTR_ERR(drvdata->dev);
+               dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
+               goto free_name;
+       }
+
+       platform_set_drvdata(pdev, drvdata);
+
+       return 0;
+
+free_name:
+       kfree(desc->name);
+       return ret;
+}
+
+static const struct of_device_id regulator_cros_ec_of_match[] = {
+       { .compatible = "google,cros-ec-regulator", },
+       {}
+};
+MODULE_DEVICE_TABLE(of, regulator_cros_ec_of_match);
+
+static struct platform_driver cros_ec_regulator_driver = {
+       .probe          = cros_ec_regulator_probe,
+       .driver         = {
+               .name           = "cros-ec-regulator",
+               .of_match_table = regulator_cros_ec_of_match,
+       },
+};
+
+module_platform_driver(cros_ec_regulator_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ChromeOS EC controlled regulator");
+MODULE_AUTHOR("Pi-Hsun Shih <pihsun@chromium.org>");