1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Support to GPOs on ROHM BD71815 |
4 | * Copyright 2021 ROHM Semiconductors. |
5 | * Author: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> |
6 | * |
7 | * Copyright 2014 Embest Technology Co. Ltd. Inc. |
8 | * Author: yanglsh@embest-tech.com |
9 | */ |
10 | |
11 | #include <linux/gpio/driver.h> |
12 | #include <linux/init.h> |
13 | #include <linux/irq.h> |
14 | #include <linux/module.h> |
15 | #include <linux/of.h> |
16 | #include <linux/platform_device.h> |
17 | /* For the BD71815 register definitions */ |
18 | #include <linux/mfd/rohm-bd71815.h> |
19 | |
20 | struct bd71815_gpio { |
21 | /* chip.parent points the MFD which provides DT node and regmap */ |
22 | struct gpio_chip chip; |
23 | /* dev points to the platform device for devm and prints */ |
24 | struct device *dev; |
25 | struct regmap *regmap; |
26 | }; |
27 | |
28 | static int bd71815gpo_get(struct gpio_chip *chip, unsigned int offset) |
29 | { |
30 | struct bd71815_gpio *bd71815 = gpiochip_get_data(gc: chip); |
31 | int ret, val; |
32 | |
33 | ret = regmap_read(map: bd71815->regmap, reg: BD71815_REG_GPO, val: &val); |
34 | if (ret) |
35 | return ret; |
36 | |
37 | return (val >> offset) & 1; |
38 | } |
39 | |
40 | static void bd71815gpo_set(struct gpio_chip *chip, unsigned int offset, |
41 | int value) |
42 | { |
43 | struct bd71815_gpio *bd71815 = gpiochip_get_data(gc: chip); |
44 | int ret, bit; |
45 | |
46 | bit = BIT(offset); |
47 | |
48 | if (value) |
49 | ret = regmap_set_bits(map: bd71815->regmap, reg: BD71815_REG_GPO, bits: bit); |
50 | else |
51 | ret = regmap_clear_bits(map: bd71815->regmap, reg: BD71815_REG_GPO, bits: bit); |
52 | |
53 | if (ret) |
54 | dev_warn(bd71815->dev, "failed to toggle GPO\n" ); |
55 | } |
56 | |
57 | static int bd71815_gpio_set_config(struct gpio_chip *chip, unsigned int offset, |
58 | unsigned long config) |
59 | { |
60 | struct bd71815_gpio *bdgpio = gpiochip_get_data(gc: chip); |
61 | |
62 | switch (pinconf_to_config_param(config)) { |
63 | case PIN_CONFIG_DRIVE_OPEN_DRAIN: |
64 | return regmap_update_bits(map: bdgpio->regmap, |
65 | reg: BD71815_REG_GPO, |
66 | BD71815_GPIO_DRIVE_MASK << offset, |
67 | BD71815_GPIO_OPEN_DRAIN << offset); |
68 | case PIN_CONFIG_DRIVE_PUSH_PULL: |
69 | return regmap_update_bits(map: bdgpio->regmap, |
70 | reg: BD71815_REG_GPO, |
71 | BD71815_GPIO_DRIVE_MASK << offset, |
72 | BD71815_GPIO_CMOS << offset); |
73 | default: |
74 | break; |
75 | } |
76 | return -ENOTSUPP; |
77 | } |
78 | |
79 | /* BD71815 GPIO is actually GPO */ |
80 | static int bd71815gpo_direction_get(struct gpio_chip *gc, unsigned int offset) |
81 | { |
82 | return GPIO_LINE_DIRECTION_OUT; |
83 | } |
84 | |
85 | /* Template for GPIO chip */ |
86 | static const struct gpio_chip bd71815gpo_chip = { |
87 | .label = "bd71815" , |
88 | .owner = THIS_MODULE, |
89 | .get = bd71815gpo_get, |
90 | .get_direction = bd71815gpo_direction_get, |
91 | .set = bd71815gpo_set, |
92 | .set_config = bd71815_gpio_set_config, |
93 | .can_sleep = true, |
94 | }; |
95 | |
96 | #define BD71815_TWO_GPIOS GENMASK(1, 0) |
97 | #define BD71815_ONE_GPIO BIT(0) |
98 | |
99 | /* |
100 | * Sigh. The BD71815 and BD71817 were originally designed to support two GPO |
101 | * pins. At some point it was noticed the second GPO pin which is the E5 pin |
102 | * located at the center of IC is hard to use on PCB (due to the location). It |
103 | * was decided to not promote this second GPO and the pin is marked as GND in |
104 | * the datasheet. The functionality is still there though! I guess driving a GPO |
105 | * connected to the ground is a bad idea. Thus we do not support it by default. |
106 | * OTOH - the original driver written by colleagues at Embest did support |
107 | * controlling this second GPO. It is thus possible this is used in some of the |
108 | * products. |
109 | * |
110 | * This driver does not by default support configuring this second GPO |
111 | * but allows using it by providing the DT property |
112 | * "rohm,enable-hidden-gpo". |
113 | */ |
114 | static int bd71815_init_valid_mask(struct gpio_chip *gc, |
115 | unsigned long *valid_mask, |
116 | unsigned int ngpios) |
117 | { |
118 | if (ngpios != 2) |
119 | return 0; |
120 | |
121 | if (gc->parent && device_property_present(dev: gc->parent, |
122 | propname: "rohm,enable-hidden-gpo" )) |
123 | *valid_mask = BD71815_TWO_GPIOS; |
124 | else |
125 | *valid_mask = BD71815_ONE_GPIO; |
126 | |
127 | return 0; |
128 | } |
129 | |
130 | static int gpo_bd71815_probe(struct platform_device *pdev) |
131 | { |
132 | struct bd71815_gpio *g; |
133 | struct device *parent, *dev; |
134 | |
135 | /* |
136 | * Bind devm lifetime to this platform device => use dev for devm. |
137 | * also the prints should originate from this device. |
138 | */ |
139 | dev = &pdev->dev; |
140 | /* The device-tree and regmap come from MFD => use parent for that */ |
141 | parent = dev->parent; |
142 | |
143 | g = devm_kzalloc(dev, size: sizeof(*g), GFP_KERNEL); |
144 | if (!g) |
145 | return -ENOMEM; |
146 | |
147 | g->chip = bd71815gpo_chip; |
148 | |
149 | /* |
150 | * FIXME: As writing of this the sysfs interface for GPIO control does |
151 | * not respect the valid_mask. Do not trust it but rather set the ngpios |
152 | * to 1 if "rohm,enable-hidden-gpo" is not given. |
153 | * |
154 | * This check can be removed later if the sysfs export is fixed and |
155 | * if the fix is backported. |
156 | * |
157 | * For now it is safest to just set the ngpios though. |
158 | */ |
159 | if (device_property_present(dev: parent, propname: "rohm,enable-hidden-gpo" )) |
160 | g->chip.ngpio = 2; |
161 | else |
162 | g->chip.ngpio = 1; |
163 | |
164 | g->chip.init_valid_mask = bd71815_init_valid_mask; |
165 | g->chip.base = -1; |
166 | g->chip.parent = parent; |
167 | g->regmap = dev_get_regmap(dev: parent, NULL); |
168 | g->dev = dev; |
169 | |
170 | return devm_gpiochip_add_data(dev, &g->chip, g); |
171 | } |
172 | |
173 | static struct platform_driver gpo_bd71815_driver = { |
174 | .driver = { |
175 | .name = "bd71815-gpo" , |
176 | }, |
177 | .probe = gpo_bd71815_probe, |
178 | }; |
179 | module_platform_driver(gpo_bd71815_driver); |
180 | |
181 | MODULE_ALIAS("platform:bd71815-gpo" ); |
182 | MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>" ); |
183 | MODULE_AUTHOR("Peter Yang <yanglsh@embest-tech.com>" ); |
184 | MODULE_DESCRIPTION("GPO interface for BD71815" ); |
185 | MODULE_LICENSE("GPL" ); |
186 | |