Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[platform/kernel/linux-starfive.git] / drivers / regulator / stm32-vrefbuf.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) STMicroelectronics 2017
4  *
5  * Author: Fabrice Gasnier <fabrice.gasnier@st.com>
6  */
7
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 /* STM32 VREFBUF registers */
20 #define STM32_VREFBUF_CSR               0x00
21
22 /* STM32 VREFBUF CSR bitfields */
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
30 struct stm32_vrefbuf {
31         void __iomem *base;
32         struct clk *clk;
33         struct device *dev;
34 };
35
36 static const unsigned int stm32_vrefbuf_voltages[] = {
37         /* Matches resp. VRS = 000b, 001b, 010b, 011b */
38         2500000, 2048000, 1800000, 1500000,
39 };
40
41 static 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          * Vrefbuf startup time depends on external capacitor: wait here for
59          * VRR to be set. That means output has reached expected value.
60          * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as
61          * arbitrary timeout.
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
78 static 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
100 static 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
119 static 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
142 static 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
163 static 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
172 static 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
183 static 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
236 err_clk_dis:
237         clk_disable_unprepare(priv->clk);
238 err_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
246 static 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
261 static 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
271 static 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
279 static 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
287 static const struct of_device_id __maybe_unused stm32_vrefbuf_of_match[] = {
288         { .compatible = "st,stm32-vrefbuf", },
289         {},
290 };
291 MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match);
292
293 static 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 };
302 module_platform_driver(stm32_vrefbuf_driver);
303
304 MODULE_LICENSE("GPL v2");
305 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
306 MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver");
307 MODULE_ALIAS("platform:stm32-vrefbuf");