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
 14struct 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
 25static 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
 50cleanup:
 51	kfree(msg);
 52	return ret;
 53}
 54
 55static 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
 67static 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
 79static 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
 95static 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
106static 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
122static 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
145static 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
154static 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
187static 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
237static const struct of_device_id regulator_cros_ec_of_match[] = {
238	{ .compatible = "google,cros-ec-regulator", },
239	{}
240};
241MODULE_DEVICE_TABLE(of, regulator_cros_ec_of_match);
242
243static 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
251module_platform_driver(cros_ec_regulator_driver);
252
253MODULE_LICENSE("GPL v2");
254MODULE_DESCRIPTION("ChromeOS EC controlled regulator");
255MODULE_AUTHOR("Pi-Hsun Shih <pihsun@chromium.org>");