1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) STMicroelectronics 2019
3 // Authors: Gabriel Fernandez <gabriel.fernandez@st.com>
4 //          Pascal Paillet <p.paillet@st.com>.
5 
6 #include <linux/io.h>
7 #include <linux/iopoll.h>
8 #include <linux/module.h>
9 #include <linux/of_address.h>
10 #include <linux/of_device.h>
11 #include <linux/platform_device.h>
12 #include <linux/regulator/driver.h>
13 #include <linux/regulator/of_regulator.h>
14 
15 /*
16  * Registers description
17  */
18 #define REG_PWR_CR3 0x0C
19 
20 #define USB_3_3_EN BIT(24)
21 #define USB_3_3_RDY BIT(26)
22 #define REG_1_8_EN BIT(28)
23 #define REG_1_8_RDY BIT(29)
24 #define REG_1_1_EN BIT(30)
25 #define REG_1_1_RDY BIT(31)
26 
27 /* list of supported regulators */
28 enum {
29 	PWR_REG11,
30 	PWR_REG18,
31 	PWR_USB33,
32 	STM32PWR_REG_NUM_REGS
33 };
34 
35 static u32 ready_mask_table[STM32PWR_REG_NUM_REGS] = {
36 	[PWR_REG11] = REG_1_1_RDY,
37 	[PWR_REG18] = REG_1_8_RDY,
38 	[PWR_USB33] = USB_3_3_RDY,
39 };
40 
41 struct stm32_pwr_reg {
42 	void __iomem *base;
43 	u32 ready_mask;
44 };
45 
stm32_pwr_reg_is_ready(struct regulator_dev * rdev)46 static int stm32_pwr_reg_is_ready(struct regulator_dev *rdev)
47 {
48 	struct stm32_pwr_reg *priv = rdev_get_drvdata(rdev);
49 	u32 val;
50 
51 	val = readl_relaxed(priv->base + REG_PWR_CR3);
52 
53 	return (val & priv->ready_mask);
54 }
55 
stm32_pwr_reg_is_enabled(struct regulator_dev * rdev)56 static int stm32_pwr_reg_is_enabled(struct regulator_dev *rdev)
57 {
58 	struct stm32_pwr_reg *priv = rdev_get_drvdata(rdev);
59 	u32 val;
60 
61 	val = readl_relaxed(priv->base + REG_PWR_CR3);
62 
63 	return (val & rdev->desc->enable_mask);
64 }
65 
stm32_pwr_reg_enable(struct regulator_dev * rdev)66 static int stm32_pwr_reg_enable(struct regulator_dev *rdev)
67 {
68 	struct stm32_pwr_reg *priv = rdev_get_drvdata(rdev);
69 	int ret;
70 	u32 val;
71 
72 	val = readl_relaxed(priv->base + REG_PWR_CR3);
73 	val |= rdev->desc->enable_mask;
74 	writel_relaxed(val, priv->base + REG_PWR_CR3);
75 
76 	/* use an arbitrary timeout of 20ms */
77 	ret = readx_poll_timeout(stm32_pwr_reg_is_ready, rdev, val, val,
78 				 100, 20 * 1000);
79 	if (ret)
80 		dev_err(&rdev->dev, "regulator enable timed out!\n");
81 
82 	return ret;
83 }
84 
stm32_pwr_reg_disable(struct regulator_dev * rdev)85 static int stm32_pwr_reg_disable(struct regulator_dev *rdev)
86 {
87 	struct stm32_pwr_reg *priv = rdev_get_drvdata(rdev);
88 	int ret;
89 	u32 val;
90 
91 	val = readl_relaxed(priv->base + REG_PWR_CR3);
92 	val &= ~rdev->desc->enable_mask;
93 	writel_relaxed(val, priv->base + REG_PWR_CR3);
94 
95 	/* use an arbitrary timeout of 20ms */
96 	ret = readx_poll_timeout(stm32_pwr_reg_is_ready, rdev, val, !val,
97 				 100, 20 * 1000);
98 	if (ret)
99 		dev_err(&rdev->dev, "regulator disable timed out!\n");
100 
101 	return ret;
102 }
103 
104 static const struct regulator_ops stm32_pwr_reg_ops = {
105 	.enable		= stm32_pwr_reg_enable,
106 	.disable	= stm32_pwr_reg_disable,
107 	.is_enabled	= stm32_pwr_reg_is_enabled,
108 };
109 
110 #define PWR_REG(_id, _name, _volt, _en, _supply) \
111 	[_id] = { \
112 		.id = _id, \
113 		.name = _name, \
114 		.of_match = of_match_ptr(_name), \
115 		.n_voltages = 1, \
116 		.type = REGULATOR_VOLTAGE, \
117 		.fixed_uV = _volt, \
118 		.ops = &stm32_pwr_reg_ops, \
119 		.enable_mask = _en, \
120 		.owner = THIS_MODULE, \
121 		.supply_name = _supply, \
122 	} \
123 
124 static const struct regulator_desc stm32_pwr_desc[] = {
125 	PWR_REG(PWR_REG11, "reg11", 1100000, REG_1_1_EN, "vdd"),
126 	PWR_REG(PWR_REG18, "reg18", 1800000, REG_1_8_EN, "vdd"),
127 	PWR_REG(PWR_USB33, "usb33", 3300000, USB_3_3_EN, "vdd_3v3_usbfs"),
128 };
129 
stm32_pwr_regulator_probe(struct platform_device * pdev)130 static int stm32_pwr_regulator_probe(struct platform_device *pdev)
131 {
132 	struct device_node *np = pdev->dev.of_node;
133 	struct stm32_pwr_reg *priv;
134 	void __iomem *base;
135 	struct regulator_dev *rdev;
136 	struct regulator_config config = { };
137 	int i, ret = 0;
138 
139 	base = of_iomap(np, 0);
140 	if (!base) {
141 		dev_err(&pdev->dev, "Unable to map IO memory\n");
142 		return -ENOMEM;
143 	}
144 
145 	config.dev = &pdev->dev;
146 
147 	for (i = 0; i < STM32PWR_REG_NUM_REGS; i++) {
148 		priv = devm_kzalloc(&pdev->dev, sizeof(struct stm32_pwr_reg),
149 				    GFP_KERNEL);
150 		if (!priv)
151 			return -ENOMEM;
152 		priv->base = base;
153 		priv->ready_mask = ready_mask_table[i];
154 		config.driver_data = priv;
155 
156 		rdev = devm_regulator_register(&pdev->dev,
157 					       &stm32_pwr_desc[i],
158 					       &config);
159 		if (IS_ERR(rdev)) {
160 			ret = PTR_ERR(rdev);
161 			dev_err(&pdev->dev,
162 				"Failed to register regulator: %d\n", ret);
163 			break;
164 		}
165 	}
166 	return ret;
167 }
168 
169 static const struct of_device_id __maybe_unused stm32_pwr_of_match[] = {
170 	{ .compatible = "st,stm32mp1,pwr-reg", },
171 	{},
172 };
173 MODULE_DEVICE_TABLE(of, stm32_pwr_of_match);
174 
175 static struct platform_driver stm32_pwr_driver = {
176 	.probe = stm32_pwr_regulator_probe,
177 	.driver = {
178 		.name  = "stm32-pwr-regulator",
179 		.of_match_table = of_match_ptr(stm32_pwr_of_match),
180 	},
181 };
182 module_platform_driver(stm32_pwr_driver);
183 
184 MODULE_DESCRIPTION("STM32MP1 PWR voltage regulator driver");
185 MODULE_AUTHOR("Pascal Paillet <p.paillet@st.com>");
186 MODULE_LICENSE("GPL v2");
187