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 ret;
68
69 ret = regmap_read(gpio->regmap, AXP20X_GPIO20_SS, &val);
70 if (ret)
71 return ret;
72
73 return !!(val & BIT(offset + 4));
74 }
75
axp20x_gpio_get_direction(struct gpio_chip * chip,unsigned offset)76 static int axp20x_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
77 {
78 struct axp20x_gpio *gpio = gpiochip_get_data(chip);
79 unsigned int val;
80 int reg, ret;
81
82 reg = axp20x_gpio_get_reg(offset);
83 if (reg < 0)
84 return reg;
85
86 ret = regmap_read(gpio->regmap, reg, &val);
87 if (ret)
88 return ret;
89
90 /*
91 * This shouldn't really happen if the pin is in use already,
92 * or if it's not in use yet, it doesn't matter since we're
93 * going to change the value soon anyway. Default to output.
94 */
95 if ((val & AXP20X_GPIO_FUNCTIONS) > 2)
96 return 0;
97
98 /*
99 * The GPIO directions are the three lowest values.
100 * 2 is input, 0 and 1 are output
101 */
102 return val & 2;
103 }
104
axp20x_gpio_output(struct gpio_chip * chip,unsigned offset,int value)105 static int axp20x_gpio_output(struct gpio_chip *chip, unsigned offset,
106 int value)
107 {
108 struct axp20x_gpio *gpio = gpiochip_get_data(chip);
109 int reg;
110
111 reg = axp20x_gpio_get_reg(offset);
112 if (reg < 0)
113 return reg;
114
115 return regmap_update_bits(gpio->regmap, reg,
116 AXP20X_GPIO_FUNCTIONS,
117 value ? AXP20X_GPIO_FUNCTION_OUT_HIGH
118 : AXP20X_GPIO_FUNCTION_OUT_LOW);
119 }
120
axp20x_gpio_set(struct gpio_chip * chip,unsigned offset,int value)121 static void axp20x_gpio_set(struct gpio_chip *chip, unsigned offset,
122 int value)
123 {
124 axp20x_gpio_output(chip, offset, value);
125 }
126
axp20x_gpio_probe(struct platform_device * pdev)127 static int axp20x_gpio_probe(struct platform_device *pdev)
128 {
129 struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
130 struct axp20x_gpio *gpio;
131 int ret;
132
133 if (!of_device_is_available(pdev->dev.of_node))
134 return -ENODEV;
135
136 if (!axp20x) {
137 dev_err(&pdev->dev, "Parent drvdata not set\n");
138 return -EINVAL;
139 }
140
141 gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
142 if (!gpio)
143 return -ENOMEM;
144
145 gpio->chip.base = -1;
146 gpio->chip.can_sleep = true;
147 gpio->chip.parent = &pdev->dev;
148 gpio->chip.label = dev_name(&pdev->dev);
149 gpio->chip.owner = THIS_MODULE;
150 gpio->chip.get = axp20x_gpio_get;
151 gpio->chip.get_direction = axp20x_gpio_get_direction;
152 gpio->chip.set = axp20x_gpio_set;
153 gpio->chip.direction_input = axp20x_gpio_input;
154 gpio->chip.direction_output = axp20x_gpio_output;
155 gpio->chip.ngpio = 3;
156
157 gpio->regmap = axp20x->regmap;
158
159 ret = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
160 if (ret) {
161 dev_err(&pdev->dev, "Failed to register GPIO chip\n");
162 return ret;
163 }
164
165 dev_info(&pdev->dev, "AXP209 GPIO driver loaded\n");
166
167 return 0;
168 }
169
170 static const struct of_device_id axp20x_gpio_match[] = {
171 { .compatible = "x-powers,axp209-gpio" },
172 { }
173 };
174 MODULE_DEVICE_TABLE(of, axp20x_gpio_match);
175
176 static struct platform_driver axp20x_gpio_driver = {
177 .probe = axp20x_gpio_probe,
178 .driver = {
179 .name = "axp20x-gpio",
180 .of_match_table = axp20x_gpio_match,
181 },
182 };
183
184 module_platform_driver(axp20x_gpio_driver);
185
186 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
187 MODULE_DESCRIPTION("AXP20x PMIC GPIO driver");
188 MODULE_LICENSE("GPL");
189