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 
cros_ec_regulator_enable(struct regulator_dev * dev)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 
cros_ec_regulator_disable(struct regulator_dev * dev)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 
cros_ec_regulator_is_enabled(struct regulator_dev * dev)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 
cros_ec_regulator_list_voltage(struct regulator_dev * dev,unsigned int selector)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 
cros_ec_regulator_get_voltage(struct regulator_dev * dev)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 
cros_ec_regulator_set_voltage(struct regulator_dev * dev,int min_uV,int max_uV,unsigned int * selector)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 
cros_ec_regulator_init_info(struct device * dev,struct cros_ec_regulator_data * data)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 
cros_ec_regulator_probe(struct platform_device * pdev)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 		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
219 		.of_match_table = regulator_cros_ec_of_match,
220 	},
221 };
222 
223 module_platform_driver(cros_ec_regulator_driver);
224 
225 MODULE_LICENSE("GPL v2");
226 MODULE_DESCRIPTION("ChromeOS EC controlled regulator");
227 MODULE_AUTHOR("Pi-Hsun Shih <pihsun@chromium.org>");
228