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