1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2018 ROHM Semiconductors
3 // gpio-bd70528.c ROHM BD70528MWV gpio driver
4
5 #include <linux/gpio/driver.h>
6 #include <linux/mfd/rohm-bd70528.h>
7 #include <linux/module.h>
8 #include <linux/platform_device.h>
9 #include <linux/regmap.h>
10
11 #define GPIO_IN_REG(offset) (BD70528_REG_GPIO1_IN + (offset) * 2)
12 #define GPIO_OUT_REG(offset) (BD70528_REG_GPIO1_OUT + (offset) * 2)
13
14 struct bd70528_gpio {
15 struct regmap *regmap;
16 struct device *dev;
17 struct gpio_chip gpio;
18 };
19
bd70528_set_debounce(struct bd70528_gpio * bdgpio,unsigned int offset,unsigned int debounce)20 static int bd70528_set_debounce(struct bd70528_gpio *bdgpio,
21 unsigned int offset, unsigned int debounce)
22 {
23 u8 val;
24
25 switch (debounce) {
26 case 0:
27 val = BD70528_DEBOUNCE_DISABLE;
28 break;
29 case 1 ... 15000:
30 val = BD70528_DEBOUNCE_15MS;
31 break;
32 case 15001 ... 30000:
33 val = BD70528_DEBOUNCE_30MS;
34 break;
35 case 30001 ... 50000:
36 val = BD70528_DEBOUNCE_50MS;
37 break;
38 default:
39 dev_err(bdgpio->dev,
40 "Invalid debounce value %u\n", debounce);
41 return -EINVAL;
42 }
43 return regmap_update_bits(bdgpio->regmap, GPIO_IN_REG(offset),
44 BD70528_DEBOUNCE_MASK, val);
45 }
46
bd70528_get_direction(struct gpio_chip * chip,unsigned int offset)47 static int bd70528_get_direction(struct gpio_chip *chip, unsigned int offset)
48 {
49 struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
50 int val, ret;
51
52 /* Do we need to do something to IRQs here? */
53 ret = regmap_read(bdgpio->regmap, GPIO_OUT_REG(offset), &val);
54 if (ret) {
55 dev_err(bdgpio->dev, "Could not read gpio direction\n");
56 return ret;
57 }
58 if (val & BD70528_GPIO_OUT_EN_MASK)
59 return GPIO_LINE_DIRECTION_OUT;
60
61 return GPIO_LINE_DIRECTION_IN;
62 }
63
bd70528_gpio_set_config(struct gpio_chip * chip,unsigned int offset,unsigned long config)64 static int bd70528_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
65 unsigned long config)
66 {
67 struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
68
69 switch (pinconf_to_config_param(config)) {
70 case PIN_CONFIG_DRIVE_OPEN_DRAIN:
71 return regmap_update_bits(bdgpio->regmap,
72 GPIO_OUT_REG(offset),
73 BD70528_GPIO_DRIVE_MASK,
74 BD70528_GPIO_OPEN_DRAIN);
75 break;
76 case PIN_CONFIG_DRIVE_PUSH_PULL:
77 return regmap_update_bits(bdgpio->regmap,
78 GPIO_OUT_REG(offset),
79 BD70528_GPIO_DRIVE_MASK,
80 BD70528_GPIO_PUSH_PULL);
81 break;
82 case PIN_CONFIG_INPUT_DEBOUNCE:
83 return bd70528_set_debounce(bdgpio, offset,
84 pinconf_to_config_argument(config));
85 break;
86 default:
87 break;
88 }
89 return -ENOTSUPP;
90 }
91
bd70528_direction_input(struct gpio_chip * chip,unsigned int offset)92 static int bd70528_direction_input(struct gpio_chip *chip, unsigned int offset)
93 {
94 struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
95
96 /* Do we need to do something to IRQs here? */
97 return regmap_update_bits(bdgpio->regmap, GPIO_OUT_REG(offset),
98 BD70528_GPIO_OUT_EN_MASK,
99 BD70528_GPIO_OUT_DISABLE);
100 }
101
bd70528_gpio_set(struct gpio_chip * chip,unsigned int offset,int value)102 static void bd70528_gpio_set(struct gpio_chip *chip, unsigned int offset,
103 int value)
104 {
105 int ret;
106 struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
107 u8 val = (value) ? BD70528_GPIO_OUT_HI : BD70528_GPIO_OUT_LO;
108
109 ret = regmap_update_bits(bdgpio->regmap, GPIO_OUT_REG(offset),
110 BD70528_GPIO_OUT_MASK, val);
111 if (ret)
112 dev_err(bdgpio->dev, "Could not set gpio to %d\n", value);
113 }
114
bd70528_direction_output(struct gpio_chip * chip,unsigned int offset,int value)115 static int bd70528_direction_output(struct gpio_chip *chip, unsigned int offset,
116 int value)
117 {
118 struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
119
120 bd70528_gpio_set(chip, offset, value);
121 return regmap_update_bits(bdgpio->regmap, GPIO_OUT_REG(offset),
122 BD70528_GPIO_OUT_EN_MASK,
123 BD70528_GPIO_OUT_ENABLE);
124 }
125
126 #define GPIO_IN_STATE_MASK(offset) (BD70528_GPIO_IN_STATE_BASE << (offset))
127
bd70528_gpio_get_o(struct bd70528_gpio * bdgpio,unsigned int offset)128 static int bd70528_gpio_get_o(struct bd70528_gpio *bdgpio, unsigned int offset)
129 {
130 int ret;
131 unsigned int val;
132
133 ret = regmap_read(bdgpio->regmap, GPIO_OUT_REG(offset), &val);
134 if (!ret)
135 ret = !!(val & BD70528_GPIO_OUT_MASK);
136 else
137 dev_err(bdgpio->dev, "GPIO (out) state read failed\n");
138
139 return ret;
140 }
141
bd70528_gpio_get_i(struct bd70528_gpio * bdgpio,unsigned int offset)142 static int bd70528_gpio_get_i(struct bd70528_gpio *bdgpio, unsigned int offset)
143 {
144 unsigned int val;
145 int ret;
146
147 ret = regmap_read(bdgpio->regmap, BD70528_REG_GPIO_STATE, &val);
148
149 if (!ret)
150 ret = !(val & GPIO_IN_STATE_MASK(offset));
151 else
152 dev_err(bdgpio->dev, "GPIO (in) state read failed\n");
153
154 return ret;
155 }
156
bd70528_gpio_get(struct gpio_chip * chip,unsigned int offset)157 static int bd70528_gpio_get(struct gpio_chip *chip, unsigned int offset)
158 {
159 int ret;
160 struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
161
162 /*
163 * There is a race condition where someone might be changing the
164 * GPIO direction after we get it but before we read the value. But
165 * application design where GPIO direction may be changed just when
166 * we read GPIO value would be pointless as reader could not know
167 * whether the returned high/low state is caused by input or output.
168 * Or then there must be other ways to mitigate the issue. Thus
169 * locking would make no sense.
170 */
171 ret = bd70528_get_direction(chip, offset);
172 if (ret == GPIO_LINE_DIRECTION_OUT)
173 ret = bd70528_gpio_get_o(bdgpio, offset);
174 else if (ret == GPIO_LINE_DIRECTION_IN)
175 ret = bd70528_gpio_get_i(bdgpio, offset);
176 else
177 dev_err(bdgpio->dev, "failed to read GPIO direction\n");
178
179 return ret;
180 }
181
bd70528_probe(struct platform_device * pdev)182 static int bd70528_probe(struct platform_device *pdev)
183 {
184 struct device *dev = &pdev->dev;
185 struct bd70528_gpio *bdgpio;
186 int ret;
187
188 bdgpio = devm_kzalloc(dev, sizeof(*bdgpio), GFP_KERNEL);
189 if (!bdgpio)
190 return -ENOMEM;
191 bdgpio->dev = dev;
192 bdgpio->gpio.parent = dev->parent;
193 bdgpio->gpio.label = "bd70528-gpio";
194 bdgpio->gpio.owner = THIS_MODULE;
195 bdgpio->gpio.get_direction = bd70528_get_direction;
196 bdgpio->gpio.direction_input = bd70528_direction_input;
197 bdgpio->gpio.direction_output = bd70528_direction_output;
198 bdgpio->gpio.set_config = bd70528_gpio_set_config;
199 bdgpio->gpio.can_sleep = true;
200 bdgpio->gpio.get = bd70528_gpio_get;
201 bdgpio->gpio.set = bd70528_gpio_set;
202 bdgpio->gpio.ngpio = 4;
203 bdgpio->gpio.base = -1;
204 #ifdef CONFIG_OF_GPIO
205 bdgpio->gpio.of_node = dev->parent->of_node;
206 #endif
207 bdgpio->regmap = dev_get_regmap(dev->parent, NULL);
208 if (!bdgpio->regmap)
209 return -ENODEV;
210
211 ret = devm_gpiochip_add_data(dev, &bdgpio->gpio, bdgpio);
212 if (ret)
213 dev_err(dev, "gpio_init: Failed to add bd70528-gpio\n");
214
215 return ret;
216 }
217
218 static struct platform_driver bd70528_gpio = {
219 .driver = {
220 .name = "bd70528-gpio"
221 },
222 .probe = bd70528_probe,
223 };
224
225 module_platform_driver(bd70528_gpio);
226
227 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
228 MODULE_DESCRIPTION("BD70528 voltage regulator driver");
229 MODULE_LICENSE("GPL");
230 MODULE_ALIAS("platform:bd70528-gpio");
231