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 int bd71828_gpio_set(struct gpio_chip *chip, unsigned int offset,
20 int value)
21 {
22 struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
23 u8 val = (value) ? BD71828_GPIO_OUT_HI : BD71828_GPIO_OUT_LO;
24
25 /*
26 * The HALL input pin can only be used as input. If this is the pin
27 * we are dealing with - then we are done
28 */
29 if (offset == HALL_GPIO_OFFSET)
30 return 0;
31
32 return regmap_update_bits(bdgpio->regmap, GPIO_OUT_REG(offset),
33 BD71828_GPIO_OUT_MASK, val);
34 }
35
bd71828_gpio_get(struct gpio_chip * chip,unsigned int offset)36 static int bd71828_gpio_get(struct gpio_chip *chip, unsigned int offset)
37 {
38 int ret;
39 unsigned int val;
40 struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
41
42 if (offset == HALL_GPIO_OFFSET)
43 ret = regmap_read(bdgpio->regmap, BD71828_REG_IO_STAT,
44 &val);
45 else
46 ret = regmap_read(bdgpio->regmap, GPIO_OUT_REG(offset),
47 &val);
48 if (!ret)
49 ret = (val & BD71828_GPIO_OUT_MASK);
50
51 return ret;
52 }
53
bd71828_gpio_set_config(struct gpio_chip * chip,unsigned int offset,unsigned long config)54 static int bd71828_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
55 unsigned long config)
56 {
57 struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
58
59 if (offset == HALL_GPIO_OFFSET)
60 return -ENOTSUPP;
61
62 switch (pinconf_to_config_param(config)) {
63 case PIN_CONFIG_DRIVE_OPEN_DRAIN:
64 return regmap_update_bits(bdgpio->regmap,
65 GPIO_OUT_REG(offset),
66 BD71828_GPIO_DRIVE_MASK,
67 BD71828_GPIO_OPEN_DRAIN);
68 case PIN_CONFIG_DRIVE_PUSH_PULL:
69 return regmap_update_bits(bdgpio->regmap,
70 GPIO_OUT_REG(offset),
71 BD71828_GPIO_DRIVE_MASK,
72 BD71828_GPIO_PUSH_PULL);
73 default:
74 break;
75 }
76 return -ENOTSUPP;
77 }
78
bd71828_get_direction(struct gpio_chip * chip,unsigned int offset)79 static int bd71828_get_direction(struct gpio_chip *chip, unsigned int offset)
80 {
81 /*
82 * Pin usage is selected by OTP data. We can't read it runtime. Hence
83 * we trust that if the pin is not excluded by "gpio-reserved-ranges"
84 * the OTP configuration is set to OUT. (Other pins but HALL input pin
85 * on BD71828 can't really be used for general purpose input - input
86 * states are used for specific cases like regulator control or
87 * PMIC_ON_REQ.
88 */
89 if (offset == HALL_GPIO_OFFSET)
90 return GPIO_LINE_DIRECTION_IN;
91
92 return GPIO_LINE_DIRECTION_OUT;
93 }
94
bd71828_probe(struct platform_device * pdev)95 static int bd71828_probe(struct platform_device *pdev)
96 {
97 struct device *dev = &pdev->dev;
98 struct bd71828_gpio *bdgpio;
99
100 bdgpio = devm_kzalloc(dev, sizeof(*bdgpio), GFP_KERNEL);
101 if (!bdgpio)
102 return -ENOMEM;
103
104 bdgpio->dev = dev;
105 bdgpio->gpio.parent = dev->parent;
106 bdgpio->gpio.label = "bd71828-gpio";
107 bdgpio->gpio.owner = THIS_MODULE;
108 bdgpio->gpio.get_direction = bd71828_get_direction;
109 bdgpio->gpio.set_config = bd71828_gpio_set_config;
110 bdgpio->gpio.can_sleep = true;
111 bdgpio->gpio.get = bd71828_gpio_get;
112 bdgpio->gpio.set_rv = bd71828_gpio_set;
113 bdgpio->gpio.base = -1;
114
115 /*
116 * See if we need some implementation to mark some PINs as
117 * not controllable based on DT info or if core can handle
118 * "gpio-reserved-ranges" and exclude them from control
119 */
120 bdgpio->gpio.ngpio = 4;
121 bdgpio->regmap = dev_get_regmap(dev->parent, NULL);
122 if (!bdgpio->regmap)
123 return -ENODEV;
124
125 return devm_gpiochip_add_data(dev, &bdgpio->gpio, bdgpio);
126 }
127
128 static struct platform_driver bd71828_gpio = {
129 .driver = {
130 .name = "bd71828-gpio"
131 },
132 .probe = bd71828_probe,
133 };
134
135 module_platform_driver(bd71828_gpio);
136
137 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
138 MODULE_DESCRIPTION("BD71828 voltage regulator driver");
139 MODULE_LICENSE("GPL");
140 MODULE_ALIAS("platform:bd71828-gpio");
141