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.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
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 /* Matches resp. VRS = 000b, 001b, 010b, 011b */
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_resume_and_get(dev: priv->dev);
48 if (ret < 0)
49 return ret;
50
51 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
52 val = (val & ~STM32_HIZ) | STM32_ENVR;
53 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
54
55 /*
56 * Vrefbuf startup time depends on external capacitor: wait here for
57 * VRR to be set. That means output has reached expected value.
58 * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as
59 * arbitrary timeout.
60 */
61 ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val,
62 val & STM32_VRR, 650, 10000);
63 if (ret) {
64 dev_err(&rdev->dev, "stm32 vrefbuf timed out!\n");
65 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
66 val = (val & ~STM32_ENVR) | STM32_HIZ;
67 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
68 }
69
70 pm_runtime_put_autosuspend(dev: priv->dev);
71
72 return ret;
73}
74
75static int stm32_vrefbuf_disable(struct regulator_dev *rdev)
76{
77 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
78 u32 val;
79 int ret;
80
81 ret = pm_runtime_resume_and_get(dev: priv->dev);
82 if (ret < 0)
83 return ret;
84
85 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
86 val &= ~STM32_ENVR;
87 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
88
89 pm_runtime_put_autosuspend(dev: priv->dev);
90
91 return 0;
92}
93
94static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev)
95{
96 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
97 int ret;
98
99 ret = pm_runtime_resume_and_get(dev: priv->dev);
100 if (ret < 0)
101 return ret;
102
103 ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR;
104
105 pm_runtime_put_autosuspend(dev: priv->dev);
106
107 return ret;
108}
109
110static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev,
111 unsigned sel)
112{
113 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
114 u32 val;
115 int ret;
116
117 ret = pm_runtime_resume_and_get(dev: priv->dev);
118 if (ret < 0)
119 return ret;
120
121 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
122 val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel);
123 writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
124
125 pm_runtime_put_autosuspend(dev: priv->dev);
126
127 return 0;
128}
129
130static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev)
131{
132 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
133 u32 val;
134 int ret;
135
136 ret = pm_runtime_resume_and_get(dev: priv->dev);
137 if (ret < 0)
138 return ret;
139
140 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
141 ret = FIELD_GET(STM32_VRS, val);
142
143 pm_runtime_put_autosuspend(dev: priv->dev);
144
145 return ret;
146}
147
148static const struct regulator_ops stm32_vrefbuf_volt_ops = {
149 .enable = stm32_vrefbuf_enable,
150 .disable = stm32_vrefbuf_disable,
151 .is_enabled = stm32_vrefbuf_is_enabled,
152 .get_voltage_sel = stm32_vrefbuf_get_voltage_sel,
153 .set_voltage_sel = stm32_vrefbuf_set_voltage_sel,
154 .list_voltage = regulator_list_voltage_table,
155};
156
157static const struct regulator_desc stm32_vrefbuf_regu = {
158 .name = "vref",
159 .supply_name = "vdda",
160 .volt_table = stm32_vrefbuf_voltages,
161 .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages),
162 .ops = &stm32_vrefbuf_volt_ops,
163 .off_on_delay = 1000,
164 .type = REGULATOR_VOLTAGE,
165 .owner = THIS_MODULE,
166};
167
168static int stm32_vrefbuf_probe(struct platform_device *pdev)
169{
170 struct stm32_vrefbuf *priv;
171 struct regulator_config config = { };
172 struct regulator_dev *rdev;
173 int ret;
174
175 priv = devm_kzalloc(dev: &pdev->dev, size: sizeof(*priv), GFP_KERNEL);
176 if (!priv)
177 return -ENOMEM;
178 priv->dev = &pdev->dev;
179
180 priv->base = devm_platform_ioremap_resource(pdev, index: 0);
181 if (IS_ERR(ptr: priv->base))
182 return PTR_ERR(ptr: priv->base);
183
184 priv->clk = devm_clk_get(dev: &pdev->dev, NULL);
185 if (IS_ERR(ptr: priv->clk))
186 return PTR_ERR(ptr: priv->clk);
187
188 pm_runtime_get_noresume(dev: &pdev->dev);
189 pm_runtime_set_active(dev: &pdev->dev);
190 pm_runtime_set_autosuspend_delay(dev: &pdev->dev,
191 STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS);
192 pm_runtime_use_autosuspend(dev: &pdev->dev);
193 pm_runtime_enable(dev: &pdev->dev);
194
195 ret = clk_prepare_enable(clk: priv->clk);
196 if (ret) {
197 dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret);
198 goto err_pm_stop;
199 }
200
201 config.dev = &pdev->dev;
202 config.driver_data = priv;
203 config.of_node = pdev->dev.of_node;
204 config.init_data = of_get_regulator_init_data(dev: &pdev->dev,
205 node: pdev->dev.of_node,
206 desc: &stm32_vrefbuf_regu);
207
208 rdev = regulator_register(dev: &pdev->dev, regulator_desc: &stm32_vrefbuf_regu, config: &config);
209 if (IS_ERR(ptr: rdev)) {
210 ret = PTR_ERR(ptr: rdev);
211 dev_err(&pdev->dev, "register failed with error %d\n", ret);
212 goto err_clk_dis;
213 }
214 platform_set_drvdata(pdev, data: rdev);
215
216 pm_runtime_put_autosuspend(dev: &pdev->dev);
217
218 return 0;
219
220err_clk_dis:
221 clk_disable_unprepare(clk: priv->clk);
222err_pm_stop:
223 pm_runtime_disable(dev: &pdev->dev);
224 pm_runtime_set_suspended(dev: &pdev->dev);
225 pm_runtime_put_noidle(dev: &pdev->dev);
226
227 return ret;
228}
229
230static void stm32_vrefbuf_remove(struct platform_device *pdev)
231{
232 struct regulator_dev *rdev = platform_get_drvdata(pdev);
233 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
234
235 pm_runtime_get_sync(dev: &pdev->dev);
236 regulator_unregister(rdev);
237 clk_disable_unprepare(clk: priv->clk);
238 pm_runtime_disable(dev: &pdev->dev);
239 pm_runtime_set_suspended(dev: &pdev->dev);
240 pm_runtime_put_noidle(dev: &pdev->dev);
241};
242
243static int __maybe_unused stm32_vrefbuf_runtime_suspend(struct device *dev)
244{
245 struct regulator_dev *rdev = dev_get_drvdata(dev);
246 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
247
248 clk_disable_unprepare(clk: priv->clk);
249
250 return 0;
251}
252
253static int __maybe_unused stm32_vrefbuf_runtime_resume(struct device *dev)
254{
255 struct regulator_dev *rdev = dev_get_drvdata(dev);
256 struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
257
258 return clk_prepare_enable(clk: priv->clk);
259}
260
261static const struct dev_pm_ops stm32_vrefbuf_pm_ops = {
262 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
263 pm_runtime_force_resume)
264 SET_RUNTIME_PM_OPS(stm32_vrefbuf_runtime_suspend,
265 stm32_vrefbuf_runtime_resume,
266 NULL)
267};
268
269static const struct of_device_id __maybe_unused stm32_vrefbuf_of_match[] = {
270 { .compatible = "st,stm32-vrefbuf", },
271 {},
272};
273MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match);
274
275static struct platform_driver stm32_vrefbuf_driver = {
276 .probe = stm32_vrefbuf_probe,
277 .remove = stm32_vrefbuf_remove,
278 .driver = {
279 .name = "stm32-vrefbuf",
280 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
281 .of_match_table = of_match_ptr(stm32_vrefbuf_of_match),
282 .pm = &stm32_vrefbuf_pm_ops,
283 },
284};
285module_platform_driver(stm32_vrefbuf_driver);
286
287MODULE_LICENSE("GPL v2");
288MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
289MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver");
290MODULE_ALIAS("platform:stm32-vrefbuf");
291

source code of linux/drivers/regulator/stm32-vrefbuf.c