summaryrefslogtreecommitdiff
path: root/drivers/regulator/stm32-vrefbuf.c
blob: 30ea3bc8ca1921ced12c21c8c418475e6864db1b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) STMicroelectronics 2017
 *
 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>
 */

#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>
#include <linux/pm_runtime.h>

/* STM32 VREFBUF registers */
#define STM32_VREFBUF_CSR		0x00

/* STM32 VREFBUF CSR bitfields */
#define STM32_VRS			GENMASK(6, 4)
#define STM32_VRR			BIT(3)
#define STM32_HIZ			BIT(1)
#define STM32_ENVR			BIT(0)

#define STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS	10

struct stm32_vrefbuf {
	void __iomem *base;
	struct clk *clk;
	struct device *dev;
};

static const unsigned int stm32_vrefbuf_voltages[] = {
	/* Matches resp. VRS = 000b, 001b, 010b, 011b */
	2500000, 2048000, 1800000, 1500000,
};

static int stm32_vrefbuf_enable(struct regulator_dev *rdev)
{
	struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
	u32 val;
	int ret;

	ret = pm_runtime_resume_and_get(priv->dev);
	if (ret < 0)
		return ret;

	val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
	val = (val & ~STM32_HIZ) | STM32_ENVR;
	writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);

	/*
	 * Vrefbuf startup time depends on external capacitor: wait here for
	 * VRR to be set. That means output has reached expected value.
	 * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as
	 * arbitrary timeout.
	 */
	ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val,
				 val & STM32_VRR, 650, 10000);
	if (ret) {
		dev_err(&rdev->dev, "stm32 vrefbuf timed out!\n");
		val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
		val = (val & ~STM32_ENVR) | STM32_HIZ;
		writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
	}

	pm_runtime_mark_last_busy(priv->dev);
	pm_runtime_put_autosuspend(priv->dev);

	return ret;
}

static int stm32_vrefbuf_disable(struct regulator_dev *rdev)
{
	struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
	u32 val;
	int ret;

	ret = pm_runtime_resume_and_get(priv->dev);
	if (ret < 0)
		return ret;

	val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
	val &= ~STM32_ENVR;
	writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);

	pm_runtime_mark_last_busy(priv->dev);
	pm_runtime_put_autosuspend(priv->dev);

	return 0;
}

static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev)
{
	struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
	int ret;

	ret = pm_runtime_resume_and_get(priv->dev);
	if (ret < 0)
		return ret;

	ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR;

	pm_runtime_mark_last_busy(priv->dev);
	pm_runtime_put_autosuspend(priv->dev);

	return ret;
}

static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev,
					 unsigned sel)
{
	struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
	u32 val;
	int ret;

	ret = pm_runtime_resume_and_get(priv->dev);
	if (ret < 0)
		return ret;

	val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
	val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel);
	writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);

	pm_runtime_mark_last_busy(priv->dev);
	pm_runtime_put_autosuspend(priv->dev);

	return 0;
}

static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev)
{
	struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
	u32 val;
	int ret;

	ret = pm_runtime_resume_and_get(priv->dev);
	if (ret < 0)
		return ret;

	val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
	ret = FIELD_GET(STM32_VRS, val);

	pm_runtime_mark_last_busy(priv->dev);
	pm_runtime_put_autosuspend(priv->dev);

	return ret;
}

static const struct regulator_ops stm32_vrefbuf_volt_ops = {
	.enable		= stm32_vrefbuf_enable,
	.disable	= stm32_vrefbuf_disable,
	.is_enabled	= stm32_vrefbuf_is_enabled,
	.get_voltage_sel = stm32_vrefbuf_get_voltage_sel,
	.set_voltage_sel = stm32_vrefbuf_set_voltage_sel,
	.list_voltage	= regulator_list_voltage_table,
};

static const struct regulator_desc stm32_vrefbuf_regu = {
	.name = "vref",
	.supply_name = "vdda",
	.volt_table = stm32_vrefbuf_voltages,
	.n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages),
	.ops = &stm32_vrefbuf_volt_ops,
	.off_on_delay = 1000,
	.type = REGULATOR_VOLTAGE,
	.owner = THIS_MODULE,
};

static int stm32_vrefbuf_probe(struct platform_device *pdev)
{
	struct stm32_vrefbuf *priv;
	struct regulator_config config = { };
	struct regulator_dev *rdev;
	int ret;

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;
	priv->dev = &pdev->dev;

	priv->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(priv->base))
		return PTR_ERR(priv->base);

	priv->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(priv->clk))
		return PTR_ERR(priv->clk);

	pm_runtime_get_noresume(&pdev->dev);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_set_autosuspend_delay(&pdev->dev,
					 STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS);
	pm_runtime_use_autosuspend(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	ret = clk_prepare_enable(priv->clk);
	if (ret) {
		dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret);
		goto err_pm_stop;
	}

	config.dev = &pdev->dev;
	config.driver_data = priv;
	config.of_node = pdev->dev.of_node;
	config.init_data = of_get_regulator_init_data(&pdev->dev,
						      pdev->dev.of_node,
						      &stm32_vrefbuf_regu);

	rdev = regulator_register(&stm32_vrefbuf_regu, &config);
	if (IS_ERR(rdev)) {
		ret = PTR_ERR(rdev);
		dev_err(&pdev->dev, "register failed with error %d\n", ret);
		goto err_clk_dis;
	}
	platform_set_drvdata(pdev, rdev);

	pm_runtime_mark_last_busy(&pdev->dev);
	pm_runtime_put_autosuspend(&pdev->dev);

	return 0;

err_clk_dis:
	clk_disable_unprepare(priv->clk);
err_pm_stop:
	pm_runtime_disable(&pdev->dev);
	pm_runtime_set_suspended(&pdev->dev);
	pm_runtime_put_noidle(&pdev->dev);

	return ret;
}

static int stm32_vrefbuf_remove(struct platform_device *pdev)
{
	struct regulator_dev *rdev = platform_get_drvdata(pdev);
	struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);

	pm_runtime_get_sync(&pdev->dev);
	regulator_unregister(rdev);
	clk_disable_unprepare(priv->clk);
	pm_runtime_disable(&pdev->dev);
	pm_runtime_set_suspended(&pdev->dev);
	pm_runtime_put_noidle(&pdev->dev);

	return 0;
};

static int __maybe_unused stm32_vrefbuf_runtime_suspend(struct device *dev)
{
	struct regulator_dev *rdev = dev_get_drvdata(dev);
	struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);

	clk_disable_unprepare(priv->clk);

	return 0;
}

static int __maybe_unused stm32_vrefbuf_runtime_resume(struct device *dev)
{
	struct regulator_dev *rdev = dev_get_drvdata(dev);
	struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);

	return clk_prepare_enable(priv->clk);
}

static const struct dev_pm_ops stm32_vrefbuf_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
				pm_runtime_force_resume)
	SET_RUNTIME_PM_OPS(stm32_vrefbuf_runtime_suspend,
			   stm32_vrefbuf_runtime_resume,
			   NULL)
};

static const struct of_device_id __maybe_unused stm32_vrefbuf_of_match[] = {
	{ .compatible = "st,stm32-vrefbuf", },
	{},
};
MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match);

static struct platform_driver stm32_vrefbuf_driver = {
	.probe = stm32_vrefbuf_probe,
	.remove = stm32_vrefbuf_remove,
	.driver = {
		.name  = "stm32-vrefbuf",
		.of_match_table = of_match_ptr(stm32_vrefbuf_of_match),
		.pm = &stm32_vrefbuf_pm_ops,
	},
};
module_platform_driver(stm32_vrefbuf_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver");
MODULE_ALIAS("platform:stm32-vrefbuf");