1 /*
2 * AXP20x GPIO driver
3 *
4 * Copyright (C) 2016 Maxime Ripard <maxime.ripard@free-electrons.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 */
11
12 #include <linux/bitops.h>
13 #include <linux/device.h>
14 #include <linux/gpio/driver.h>
15 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel.h>
18 #include <linux/mfd/axp20x.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/platform_device.h>
22 #include <linux/regmap.h>
23 #include <linux/slab.h>
24
25 #define AXP20X_GPIO_FUNCTIONS 0x7
26 #define AXP20X_GPIO_FUNCTION_OUT_LOW 0
27 #define AXP20X_GPIO_FUNCTION_OUT_HIGH 1
28 #define AXP20X_GPIO_FUNCTION_INPUT 2
29
30 struct axp20x_gpio {
31 struct gpio_chip chip;
32 struct regmap *regmap;
33 };
34
axp20x_gpio_get_reg(unsigned offset)35 static int axp20x_gpio_get_reg(unsigned offset)
36 {
37 switch (offset) {
38 case 0:
39 return AXP20X_GPIO0_CTRL;
40 case 1:
41 return AXP20X_GPIO1_CTRL;
42 case 2:
43 return AXP20X_GPIO2_CTRL;
44 }
45
46 return -EINVAL;
47 }
48
axp20x_gpio_input(struct gpio_chip * chip,unsigned offset)49 static int axp20x_gpio_input(struct gpio_chip *chip, unsigned offset)
50 {
51 struct axp20x_gpio *gpio = gpiochip_get_data(chip);
52 int reg;
53
54 reg = axp20x_gpio_get_reg(offset);
55 if (reg < 0)
56 return reg;
57
58 return regmap_update_bits(gpio->regmap, reg,
59 AXP20X_GPIO_FUNCTIONS,
60 AXP20X_GPIO_FUNCTION_INPUT);
61 }
62
axp20x_gpio_get(struct gpio_chip * chip,unsigned offset)63 static int axp20x_gpio_get(struct gpio_chip *chip, unsigned offset)
64 {
65 struct axp20x_gpio *gpio = gpiochip_get_data(chip);
66 unsigned int val;
67 int reg, ret;
68
69 reg = axp20x_gpio_get_reg(offset);
70 if (reg < 0)
71 return reg;
72
73 ret = regmap_read(gpio->regmap, reg, &val);
74 if (ret)
75 return ret;
76
77 return !!(val & BIT(offset + 4));
78 }
79
axp20x_gpio_get_direction(struct gpio_chip * chip,unsigned offset)80 static int axp20x_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
81 {
82 struct axp20x_gpio *gpio = gpiochip_get_data(chip);
83 unsigned int val;
84 int reg, ret;
85
86 reg = axp20x_gpio_get_reg(offset);
87 if (reg < 0)
88 return reg;
89
90 ret = regmap_read(gpio->regmap, reg, &val);
91 if (ret)
92 return ret;
93
94 /*
95 * This shouldn't really happen if the pin is in use already,
96 * or if it's not in use yet, it doesn't matter since we're
97 * going to change the value soon anyway. Default to output.
98 */
99 if ((val & AXP20X_GPIO_FUNCTIONS) > 2)
100 return 0;
101
102 /*
103 * The GPIO directions are the three lowest values.
104 * 2 is input, 0 and 1 are output
105 */
106 return val & 2;
107 }
108
axp20x_gpio_output(struct gpio_chip * chip,unsigned offset,int value)109 static int axp20x_gpio_output(struct gpio_chip *chip, unsigned offset,
110 int value)
111 {
112 struct axp20x_gpio *gpio = gpiochip_get_data(chip);
113 int reg;
114
115 reg = axp20x_gpio_get_reg(offset);
116 if (reg < 0)
117 return reg;
118
119 return regmap_update_bits(gpio->regmap, reg,
120 AXP20X_GPIO_FUNCTIONS,
121 value ? AXP20X_GPIO_FUNCTION_OUT_HIGH
122 : AXP20X_GPIO_FUNCTION_OUT_LOW);
123 }
124
axp20x_gpio_set(struct gpio_chip * chip,unsigned offset,int value)125 static void axp20x_gpio_set(struct gpio_chip *chip, unsigned offset,
126 int value)
127 {
128 axp20x_gpio_output(chip, offset, value);
129 }
130
axp20x_gpio_probe(struct platform_device * pdev)131 static int axp20x_gpio_probe(struct platform_device *pdev)
132 {
133 struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
134 struct axp20x_gpio *gpio;
135 int ret;
136
137 if (!of_device_is_available(pdev->dev.of_node))
138 return -ENODEV;
139
140 if (!axp20x) {
141 dev_err(&pdev->dev, "Parent drvdata not set\n");
142 return -EINVAL;
143 }
144
145 gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
146 if (!gpio)
147 return -ENOMEM;
148
149 gpio->chip.base = -1;
150 gpio->chip.can_sleep = true;
151 gpio->chip.parent = &pdev->dev;
152 gpio->chip.label = dev_name(&pdev->dev);
153 gpio->chip.owner = THIS_MODULE;
154 gpio->chip.get = axp20x_gpio_get;
155 gpio->chip.get_direction = axp20x_gpio_get_direction;
156 gpio->chip.set = axp20x_gpio_set;
157 gpio->chip.direction_input = axp20x_gpio_input;
158 gpio->chip.direction_output = axp20x_gpio_output;
159 gpio->chip.ngpio = 3;
160
161 gpio->regmap = axp20x->regmap;
162
163 ret = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
164 if (ret) {
165 dev_err(&pdev->dev, "Failed to register GPIO chip\n");
166 return ret;
167 }
168
169 dev_info(&pdev->dev, "AXP209 GPIO driver loaded\n");
170
171 return 0;
172 }
173
174 static const struct of_device_id axp20x_gpio_match[] = {
175 { .compatible = "x-powers,axp209-gpio" },
176 { }
177 };
178 MODULE_DEVICE_TABLE(of, axp20x_gpio_match);
179
180 static struct platform_driver axp20x_gpio_driver = {
181 .probe = axp20x_gpio_probe,
182 .driver = {
183 .name = "axp20x-gpio",
184 .of_match_table = axp20x_gpio_match,
185 },
186 };
187
188 module_platform_driver(axp20x_gpio_driver);
189
190 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
191 MODULE_DESCRIPTION("AXP20x PMIC GPIO driver");
192 MODULE_LICENSE("GPL");
193