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8#include <linux/bitfield.h>
9#include <linux/clk.h>
10#include <linux/io.h>
11#include <linux/iopoll.h>
12#include <linux/module.h>
13#include <linux/of_device.h>
14#include <linux/platform_device.h>
15#include <linux/regulator/driver.h>
16#include <linux/regulator/of_regulator.h>
17#include <linux/pm_runtime.h>
18
19
20#define STM32_VREFBUF_CSR 0x00
21
22
23#define STM32_VRS GENMASK(6, 4)
24#define STM32_VRR BIT(3)
25#define STM32_HIZ BIT(1)
26#define STM32_ENVR BIT(0)
27
28#define STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS 10
29
30struct stm32_vrefbuf {
31 void __iomem *base;
32 struct clk *clk;
33 struct device *dev;
34};
35
36static const unsigned int stm32_vrefbuf_voltages[] = {
37
38 2500000, 2048000, 1800000, 1500000,
39};
40
41static int stm32_vrefbuf_enable(struct regulator_dev *rdev)
42{
43 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
44 u32 val;
45 int ret;
46
47 ret = pm_runtime_get_sync(priv->dev);
48 if (ret < 0) {
49 pm_runtime_put_noidle(priv->dev);
50 return ret;
51 }
52
53 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
54 val = (val & ~STM32_HIZ) | STM32_ENVR;
55 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
56
57
58
59
60
61
62
63 ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val,
64 val & STM32_VRR, 650, 10000);
65 if (ret) {
66 dev_err(&rdev->dev, "stm32 vrefbuf timed out!\n");
67 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
68 val = (val & ~STM32_ENVR) | STM32_HIZ;
69 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
70 }
71
72 pm_runtime_mark_last_busy(priv->dev);
73 pm_runtime_put_autosuspend(priv->dev);
74
75 return ret;
76}
77
78static int stm32_vrefbuf_disable(struct regulator_dev *rdev)
79{
80 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
81 u32 val;
82 int ret;
83
84 ret = pm_runtime_get_sync(priv->dev);
85 if (ret < 0) {
86 pm_runtime_put_noidle(priv->dev);
87 return ret;
88 }
89
90 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
91 val &= ~STM32_ENVR;
92 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
93
94 pm_runtime_mark_last_busy(priv->dev);
95 pm_runtime_put_autosuspend(priv->dev);
96
97 return 0;
98}
99
100static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev)
101{
102 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
103 int ret;
104
105 ret = pm_runtime_get_sync(priv->dev);
106 if (ret < 0) {
107 pm_runtime_put_noidle(priv->dev);
108 return ret;
109 }
110
111 ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR;
112
113 pm_runtime_mark_last_busy(priv->dev);
114 pm_runtime_put_autosuspend(priv->dev);
115
116 return ret;
117}
118
119static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev,
120 unsigned sel)
121{
122 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
123 u32 val;
124 int ret;
125
126 ret = pm_runtime_get_sync(priv->dev);
127 if (ret < 0) {
128 pm_runtime_put_noidle(priv->dev);
129 return ret;
130 }
131
132 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
133 val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel);
134 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
135
136 pm_runtime_mark_last_busy(priv->dev);
137 pm_runtime_put_autosuspend(priv->dev);
138
139 return 0;
140}
141
142static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev)
143{
144 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
145 u32 val;
146 int ret;
147
148 ret = pm_runtime_get_sync(priv->dev);
149 if (ret < 0) {
150 pm_runtime_put_noidle(priv->dev);
151 return ret;
152 }
153
154 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
155 ret = FIELD_GET(STM32_VRS, val);
156
157 pm_runtime_mark_last_busy(priv->dev);
158 pm_runtime_put_autosuspend(priv->dev);
159
160 return ret;
161}
162
163static const struct regulator_ops stm32_vrefbuf_volt_ops = {
164 .enable = stm32_vrefbuf_enable,
165 .disable = stm32_vrefbuf_disable,
166 .is_enabled = stm32_vrefbuf_is_enabled,
167 .get_voltage_sel = stm32_vrefbuf_get_voltage_sel,
168 .set_voltage_sel = stm32_vrefbuf_set_voltage_sel,
169 .list_voltage = regulator_list_voltage_table,
170};
171
172static const struct regulator_desc stm32_vrefbuf_regu = {
173 .name = "vref",
174 .supply_name = "vdda",
175 .volt_table = stm32_vrefbuf_voltages,
176 .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages),
177 .ops = &stm32_vrefbuf_volt_ops,
178 .off_on_delay = 1000,
179 .type = REGULATOR_VOLTAGE,
180 .owner = THIS_MODULE,
181};
182
183static int stm32_vrefbuf_probe(struct platform_device *pdev)
184{
185 struct stm32_vrefbuf *priv;
186 struct regulator_config config = { };
187 struct regulator_dev *rdev;
188 int ret;
189
190 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
191 if (!priv)
192 return -ENOMEM;
193 priv->dev = &pdev->dev;
194
195 priv->base = devm_platform_ioremap_resource(pdev, 0);
196 if (IS_ERR(priv->base))
197 return PTR_ERR(priv->base);
198
199 priv->clk = devm_clk_get(&pdev->dev, NULL);
200 if (IS_ERR(priv->clk))
201 return PTR_ERR(priv->clk);
202
203 pm_runtime_get_noresume(&pdev->dev);
204 pm_runtime_set_active(&pdev->dev);
205 pm_runtime_set_autosuspend_delay(&pdev->dev,
206 STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS);
207 pm_runtime_use_autosuspend(&pdev->dev);
208 pm_runtime_enable(&pdev->dev);
209
210 ret = clk_prepare_enable(priv->clk);
211 if (ret) {
212 dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret);
213 goto err_pm_stop;
214 }
215
216 config.dev = &pdev->dev;
217 config.driver_data = priv;
218 config.of_node = pdev->dev.of_node;
219 config.init_data = of_get_regulator_init_data(&pdev->dev,
220 pdev->dev.of_node,
221 &stm32_vrefbuf_regu);
222
223 rdev = regulator_register(&stm32_vrefbuf_regu, &config);
224 if (IS_ERR(rdev)) {
225 ret = PTR_ERR(rdev);
226 dev_err(&pdev->dev, "register failed with error %d\n", ret);
227 goto err_clk_dis;
228 }
229 platform_set_drvdata(pdev, rdev);
230
231 pm_runtime_mark_last_busy(&pdev->dev);
232 pm_runtime_put_autosuspend(&pdev->dev);
233
234 return 0;
235
236err_clk_dis:
237 clk_disable_unprepare(priv->clk);
238err_pm_stop:
239 pm_runtime_disable(&pdev->dev);
240 pm_runtime_set_suspended(&pdev->dev);
241 pm_runtime_put_noidle(&pdev->dev);
242
243 return ret;
244}
245
246static int stm32_vrefbuf_remove(struct platform_device *pdev)
247{
248 struct regulator_dev *rdev = platform_get_drvdata(pdev);
249 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
250
251 pm_runtime_get_sync(&pdev->dev);
252 regulator_unregister(rdev);
253 clk_disable_unprepare(priv->clk);
254 pm_runtime_disable(&pdev->dev);
255 pm_runtime_set_suspended(&pdev->dev);
256 pm_runtime_put_noidle(&pdev->dev);
257
258 return 0;
259};
260
261static int __maybe_unused stm32_vrefbuf_runtime_suspend(struct device *dev)
262{
263 struct regulator_dev *rdev = dev_get_drvdata(dev);
264 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
265
266 clk_disable_unprepare(priv->clk);
267
268 return 0;
269}
270
271static int __maybe_unused stm32_vrefbuf_runtime_resume(struct device *dev)
272{
273 struct regulator_dev *rdev = dev_get_drvdata(dev);
274 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
275
276 return clk_prepare_enable(priv->clk);
277}
278
279static const struct dev_pm_ops stm32_vrefbuf_pm_ops = {
280 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
281 pm_runtime_force_resume)
282 SET_RUNTIME_PM_OPS(stm32_vrefbuf_runtime_suspend,
283 stm32_vrefbuf_runtime_resume,
284 NULL)
285};
286
287static const struct of_device_id __maybe_unused stm32_vrefbuf_of_match[] = {
288 { .compatible = "st,stm32-vrefbuf", },
289 {},
290};
291MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match);
292
293static struct platform_driver stm32_vrefbuf_driver = {
294 .probe = stm32_vrefbuf_probe,
295 .remove = stm32_vrefbuf_remove,
296 .driver = {
297 .name = "stm32-vrefbuf",
298 .of_match_table = of_match_ptr(stm32_vrefbuf_of_match),
299 .pm = &stm32_vrefbuf_pm_ops,
300 },
301};
302module_platform_driver(stm32_vrefbuf_driver);
303
304MODULE_LICENSE("GPL v2");
305MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
306MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver");
307MODULE_ALIAS("platform:stm32-vrefbuf");
308
