1 // SPDX-License-Identifier: GPL-2.0-only
2 // Copyright (C) 2018 ROHM Semiconductors
3
4 #include <linux/gpio/driver.h>
5 #include <linux/mfd/rohm-bd71828.h>
6 #include <linux/module.h>
7 #include <linux/platform_device.h>
8 #include <linux/regmap.h>
9
10 #define GPIO_OUT_REG(off) (BD71828_REG_GPIO_CTRL1 + (off))
11 #define HALL_GPIO_OFFSET 3
12
13 struct bd71828_gpio {
14 struct regmap *regmap;
15 struct device *dev;
16 struct gpio_chip gpio;
17 };
18
bd71828_gpio_set(struct gpio_chip * chip,unsigned int offset,int value)19 static void bd71828_gpio_set(struct gpio_chip *chip, unsigned int offset,
20 int value)
21 {
22 int ret;
23 struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
24 u8 val = (value) ? BD71828_GPIO_OUT_HI : BD71828_GPIO_OUT_LO;
25
26 /*
27 * The HALL input pin can only be used as input. If this is the pin
28 * we are dealing with - then we are done
29 */
30 if (offset == HALL_GPIO_OFFSET)
31 return;
32
33 ret = regmap_update_bits(bdgpio->regmap, GPIO_OUT_REG(offset),
34 BD71828_GPIO_OUT_MASK, val);
35 if (ret)
36 dev_err(bdgpio->dev, "Could not set gpio to %d\n", value);
37 }
38
bd71828_gpio_get(struct gpio_chip * chip,unsigned int offset)39 static int bd71828_gpio_get(struct gpio_chip *chip, unsigned int offset)
40 {
41 int ret;
42 unsigned int val;
43 struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
44
45 if (offset == HALL_GPIO_OFFSET)
46 ret = regmap_read(bdgpio->regmap, BD71828_REG_IO_STAT,
47 &val);
48 else
49 ret = regmap_read(bdgpio->regmap, GPIO_OUT_REG(offset),
50 &val);
51 if (!ret)
52 ret = (val & BD71828_GPIO_OUT_MASK);
53
54 return ret;
55 }
56
bd71828_gpio_set_config(struct gpio_chip * chip,unsigned int offset,unsigned long config)57 static int bd71828_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
58 unsigned long config)
59 {
60 struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
61
62 if (offset == HALL_GPIO_OFFSET)
63 return -ENOTSUPP;
64
65 switch (pinconf_to_config_param(config)) {
66 case PIN_CONFIG_DRIVE_OPEN_DRAIN:
67 return regmap_update_bits(bdgpio->regmap,
68 GPIO_OUT_REG(offset),
69 BD71828_GPIO_DRIVE_MASK,
70 BD71828_GPIO_OPEN_DRAIN);
71 case PIN_CONFIG_DRIVE_PUSH_PULL:
72 return regmap_update_bits(bdgpio->regmap,
73 GPIO_OUT_REG(offset),
74 BD71828_GPIO_DRIVE_MASK,
75 BD71828_GPIO_PUSH_PULL);
76 default:
77 break;
78 }
79 return -ENOTSUPP;
80 }
81
bd71828_get_direction(struct gpio_chip * chip,unsigned int offset)82 static int bd71828_get_direction(struct gpio_chip *chip, unsigned int offset)
83 {
84 /*
85 * Pin usage is selected by OTP data. We can't read it runtime. Hence
86 * we trust that if the pin is not excluded by "gpio-reserved-ranges"
87 * the OTP configuration is set to OUT. (Other pins but HALL input pin
88 * on BD71828 can't really be used for general purpose input - input
89 * states are used for specific cases like regulator control or
90 * PMIC_ON_REQ.
91 */
92 if (offset == HALL_GPIO_OFFSET)
93 return GPIO_LINE_DIRECTION_IN;
94
95 return GPIO_LINE_DIRECTION_OUT;
96 }
97
bd71828_probe(struct platform_device * pdev)98 static int bd71828_probe(struct platform_device *pdev)
99 {
100 struct device *dev = &pdev->dev;
101 struct bd71828_gpio *bdgpio;
102
103 bdgpio = devm_kzalloc(dev, sizeof(*bdgpio), GFP_KERNEL);
104 if (!bdgpio)
105 return -ENOMEM;
106
107 bdgpio->dev = dev;
108 bdgpio->gpio.parent = dev->parent;
109 bdgpio->gpio.label = "bd71828-gpio";
110 bdgpio->gpio.owner = THIS_MODULE;
111 bdgpio->gpio.get_direction = bd71828_get_direction;
112 bdgpio->gpio.set_config = bd71828_gpio_set_config;
113 bdgpio->gpio.can_sleep = true;
114 bdgpio->gpio.get = bd71828_gpio_get;
115 bdgpio->gpio.set = bd71828_gpio_set;
116 bdgpio->gpio.base = -1;
117
118 /*
119 * See if we need some implementation to mark some PINs as
120 * not controllable based on DT info or if core can handle
121 * "gpio-reserved-ranges" and exclude them from control
122 */
123 bdgpio->gpio.ngpio = 4;
124 bdgpio->regmap = dev_get_regmap(dev->parent, NULL);
125 if (!bdgpio->regmap)
126 return -ENODEV;
127
128 return devm_gpiochip_add_data(dev, &bdgpio->gpio, bdgpio);
129 }
130
131 static struct platform_driver bd71828_gpio = {
132 .driver = {
133 .name = "bd71828-gpio"
134 },
135 .probe = bd71828_probe,
136 };
137
138 module_platform_driver(bd71828_gpio);
139
140 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
141 MODULE_DESCRIPTION("BD71828 voltage regulator driver");
142 MODULE_LICENSE("GPL");
143 MODULE_ALIAS("platform:bd71828-gpio");
144