1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * This file is part of STM32 DAC driver
4 *
5 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
6 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
7 *
8 */
9
10 #include <linux/clk.h>
11 #include <linux/delay.h>
12 #include <linux/mod_devicetable.h>
13 #include <linux/module.h>
14 #include <linux/of_platform.h>
15 #include <linux/platform_device.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/property.h>
18 #include <linux/regulator/consumer.h>
19 #include <linux/reset.h>
20
21 #include "stm32-dac-core.h"
22
23 /**
24 * struct stm32_dac_priv - stm32 DAC core private data
25 * @pclk: peripheral clock common for all DACs
26 * @vref: regulator reference
27 * @common: Common data for all DAC instances
28 */
29 struct stm32_dac_priv {
30 struct clk *pclk;
31 struct regulator *vref;
32 struct stm32_dac_common common;
33 };
34
35 /**
36 * struct stm32_dac_cfg - DAC configuration
37 * @has_hfsel: DAC has high frequency control
38 */
39 struct stm32_dac_cfg {
40 bool has_hfsel;
41 };
42
to_stm32_dac_priv(struct stm32_dac_common * com)43 static struct stm32_dac_priv *to_stm32_dac_priv(struct stm32_dac_common *com)
44 {
45 return container_of(com, struct stm32_dac_priv, common);
46 }
47
48 static const struct regmap_config stm32_dac_regmap_cfg = {
49 .reg_bits = 32,
50 .val_bits = 32,
51 .reg_stride = sizeof(u32),
52 .max_register = 0x3fc,
53 };
54
stm32_dac_core_hw_start(struct device * dev)55 static int stm32_dac_core_hw_start(struct device *dev)
56 {
57 struct stm32_dac_common *common = dev_get_drvdata(dev);
58 struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
59 int ret;
60
61 ret = regulator_enable(priv->vref);
62 if (ret < 0) {
63 dev_err(dev, "vref enable failed: %d\n", ret);
64 return ret;
65 }
66
67 ret = clk_prepare_enable(priv->pclk);
68 if (ret < 0) {
69 dev_err(dev, "pclk enable failed: %d\n", ret);
70 goto err_regulator_disable;
71 }
72
73 return 0;
74
75 err_regulator_disable:
76 regulator_disable(priv->vref);
77
78 return ret;
79 }
80
stm32_dac_core_hw_stop(struct device * dev)81 static void stm32_dac_core_hw_stop(struct device *dev)
82 {
83 struct stm32_dac_common *common = dev_get_drvdata(dev);
84 struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
85
86 clk_disable_unprepare(priv->pclk);
87 regulator_disable(priv->vref);
88 }
89
stm32_dac_probe(struct platform_device * pdev)90 static int stm32_dac_probe(struct platform_device *pdev)
91 {
92 struct device *dev = &pdev->dev;
93 const struct stm32_dac_cfg *cfg;
94 struct stm32_dac_priv *priv;
95 struct regmap *regmap;
96 void __iomem *mmio;
97 struct reset_control *rst;
98 int ret;
99
100 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
101 if (!priv)
102 return -ENOMEM;
103 platform_set_drvdata(pdev, &priv->common);
104
105 cfg = device_get_match_data(dev);
106
107 mmio = devm_platform_ioremap_resource(pdev, 0);
108 if (IS_ERR(mmio))
109 return PTR_ERR(mmio);
110
111 regmap = devm_regmap_init_mmio_clk(dev, "pclk", mmio,
112 &stm32_dac_regmap_cfg);
113 if (IS_ERR(regmap))
114 return PTR_ERR(regmap);
115 priv->common.regmap = regmap;
116
117 priv->pclk = devm_clk_get(dev, "pclk");
118 if (IS_ERR(priv->pclk))
119 return dev_err_probe(dev, PTR_ERR(priv->pclk), "pclk get failed\n");
120
121 priv->vref = devm_regulator_get(dev, "vref");
122 if (IS_ERR(priv->vref))
123 return dev_err_probe(dev, PTR_ERR(priv->vref), "vref get failed\n");
124
125 pm_runtime_get_noresume(dev);
126 pm_runtime_set_active(dev);
127 pm_runtime_enable(dev);
128
129 ret = stm32_dac_core_hw_start(dev);
130 if (ret)
131 goto err_pm_stop;
132
133 ret = regulator_get_voltage(priv->vref);
134 if (ret < 0) {
135 dev_err(dev, "vref get voltage failed, %d\n", ret);
136 goto err_hw_stop;
137 }
138 priv->common.vref_mv = ret / 1000;
139 dev_dbg(dev, "vref+=%dmV\n", priv->common.vref_mv);
140
141 rst = devm_reset_control_get_optional_exclusive(dev, NULL);
142 if (rst) {
143 if (IS_ERR(rst)) {
144 ret = dev_err_probe(dev, PTR_ERR(rst), "reset get failed\n");
145 goto err_hw_stop;
146 }
147
148 reset_control_assert(rst);
149 udelay(2);
150 reset_control_deassert(rst);
151 }
152
153 if (cfg && cfg->has_hfsel) {
154 /* When clock speed is higher than 80MHz, set HFSEL */
155 priv->common.hfsel = (clk_get_rate(priv->pclk) > 80000000UL);
156 ret = regmap_update_bits(regmap, STM32_DAC_CR,
157 STM32H7_DAC_CR_HFSEL,
158 priv->common.hfsel ?
159 STM32H7_DAC_CR_HFSEL : 0);
160 if (ret)
161 goto err_hw_stop;
162 }
163
164
165 ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, dev);
166 if (ret < 0) {
167 dev_err(dev, "failed to populate DT children\n");
168 goto err_hw_stop;
169 }
170
171 pm_runtime_put(dev);
172
173 return 0;
174
175 err_hw_stop:
176 stm32_dac_core_hw_stop(dev);
177 err_pm_stop:
178 pm_runtime_disable(dev);
179 pm_runtime_set_suspended(dev);
180 pm_runtime_put_noidle(dev);
181
182 return ret;
183 }
184
stm32_dac_remove(struct platform_device * pdev)185 static void stm32_dac_remove(struct platform_device *pdev)
186 {
187 pm_runtime_get_sync(&pdev->dev);
188 of_platform_depopulate(&pdev->dev);
189 stm32_dac_core_hw_stop(&pdev->dev);
190 pm_runtime_disable(&pdev->dev);
191 pm_runtime_set_suspended(&pdev->dev);
192 pm_runtime_put_noidle(&pdev->dev);
193 }
194
stm32_dac_core_resume(struct device * dev)195 static int stm32_dac_core_resume(struct device *dev)
196 {
197 struct stm32_dac_common *common = dev_get_drvdata(dev);
198 struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
199 int ret;
200
201 if (priv->common.hfsel) {
202 /* restore hfsel (maybe lost under low power state) */
203 ret = regmap_set_bits(priv->common.regmap, STM32_DAC_CR,
204 STM32H7_DAC_CR_HFSEL);
205 if (ret)
206 return ret;
207 }
208
209 return pm_runtime_force_resume(dev);
210 }
211
stm32_dac_core_runtime_suspend(struct device * dev)212 static int stm32_dac_core_runtime_suspend(struct device *dev)
213 {
214 stm32_dac_core_hw_stop(dev);
215
216 return 0;
217 }
218
stm32_dac_core_runtime_resume(struct device * dev)219 static int stm32_dac_core_runtime_resume(struct device *dev)
220 {
221 return stm32_dac_core_hw_start(dev);
222 }
223
224 static const struct dev_pm_ops stm32_dac_core_pm_ops = {
225 SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, stm32_dac_core_resume)
226 RUNTIME_PM_OPS(stm32_dac_core_runtime_suspend,
227 stm32_dac_core_runtime_resume,
228 NULL)
229 };
230
231 static const struct stm32_dac_cfg stm32h7_dac_cfg = {
232 .has_hfsel = true,
233 };
234
235 static const struct of_device_id stm32_dac_of_match[] = {
236 {
237 .compatible = "st,stm32f4-dac-core",
238 }, {
239 .compatible = "st,stm32h7-dac-core",
240 .data = (void *)&stm32h7_dac_cfg,
241 },
242 {},
243 };
244 MODULE_DEVICE_TABLE(of, stm32_dac_of_match);
245
246 static struct platform_driver stm32_dac_driver = {
247 .probe = stm32_dac_probe,
248 .remove_new = stm32_dac_remove,
249 .driver = {
250 .name = "stm32-dac-core",
251 .of_match_table = stm32_dac_of_match,
252 .pm = pm_ptr(&stm32_dac_core_pm_ops),
253 },
254 };
255 module_platform_driver(stm32_dac_driver);
256
257 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
258 MODULE_DESCRIPTION("STMicroelectronics STM32 DAC core driver");
259 MODULE_LICENSE("GPL v2");
260 MODULE_ALIAS("platform:stm32-dac-core");
261