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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Digital I/O driver for Technologic Systems I2C FPGA Core
4 *
5 * Copyright (C) 2015, 2018 Technologic Systems
6 * Copyright (C) 2016 Savoir-Faire Linux
7 */
8
9#include <linux/gpio/driver.h>
10#include <linux/i2c.h>
11#include <linux/of_device.h>
12#include <linux/module.h>
13#include <linux/regmap.h>
14
15#define DEFAULT_PIN_NUMBER 32
16/*
17 * Register bits used by the GPIO device
18 * Some boards, such as TS-7970 do not have a separate input bit
19 */
20#define TS4900_GPIO_OE 0x01
21#define TS4900_GPIO_OUT 0x02
22#define TS4900_GPIO_IN 0x04
23#define TS7970_GPIO_IN 0x02
24
25struct ts4900_gpio_priv {
26 struct regmap *regmap;
27 struct gpio_chip gpio_chip;
28 unsigned int input_bit;
29};
30
31static int ts4900_gpio_get_direction(struct gpio_chip *chip,
32 unsigned int offset)
33{
34 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
35 unsigned int reg;
36
37 regmap_read(priv->regmap, offset, ®);
38
39 if (reg & TS4900_GPIO_OE)
40 return GPIO_LINE_DIRECTION_OUT;
41
42 return GPIO_LINE_DIRECTION_IN;
43}
44
45static int ts4900_gpio_direction_input(struct gpio_chip *chip,
46 unsigned int offset)
47{
48 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
49
50 /*
51 * Only clear the OE bit here, requires a RMW. Prevents a potential issue
52 * with OE and DAT getting to the physical pin at different times.
53 */
54 return regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OE, 0);
55}
56
57static int ts4900_gpio_direction_output(struct gpio_chip *chip,
58 unsigned int offset, int value)
59{
60 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
61 unsigned int reg;
62 int ret;
63
64 /*
65 * If changing from an input to an output, we need to first set the
66 * GPIO's DAT bit to what is requested and then set the OE bit. This
67 * prevents a glitch that can occur on the IO line.
68 */
69 regmap_read(priv->regmap, offset, ®);
70 if (!(reg & TS4900_GPIO_OE)) {
71 if (value)
72 reg = TS4900_GPIO_OUT;
73 else
74 reg &= ~TS4900_GPIO_OUT;
75
76 regmap_write(priv->regmap, offset, reg);
77 }
78
79 if (value)
80 ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE |
81 TS4900_GPIO_OUT);
82 else
83 ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE);
84
85 return ret;
86}
87
88static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset)
89{
90 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
91 unsigned int reg;
92
93 regmap_read(priv->regmap, offset, ®);
94
95 return !!(reg & priv->input_bit);
96}
97
98static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset,
99 int value)
100{
101 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
102
103 if (value)
104 regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT,
105 TS4900_GPIO_OUT);
106 else
107 regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0);
108}
109
110static const struct regmap_config ts4900_regmap_config = {
111 .reg_bits = 16,
112 .val_bits = 8,
113};
114
115static const struct gpio_chip template_chip = {
116 .label = "ts4900-gpio",
117 .owner = THIS_MODULE,
118 .get_direction = ts4900_gpio_get_direction,
119 .direction_input = ts4900_gpio_direction_input,
120 .direction_output = ts4900_gpio_direction_output,
121 .get = ts4900_gpio_get,
122 .set = ts4900_gpio_set,
123 .base = -1,
124 .can_sleep = true,
125};
126
127static const struct of_device_id ts4900_gpio_of_match_table[] = {
128 {
129 .compatible = "technologic,ts4900-gpio",
130 .data = (void *)TS4900_GPIO_IN,
131 }, {
132 .compatible = "technologic,ts7970-gpio",
133 .data = (void *)TS7970_GPIO_IN,
134 },
135 { /* sentinel */ },
136};
137MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table);
138
139static int ts4900_gpio_probe(struct i2c_client *client)
140{
141 struct ts4900_gpio_priv *priv;
142 u32 ngpio;
143 int ret;
144
145 if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio))
146 ngpio = DEFAULT_PIN_NUMBER;
147
148 priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
149 if (!priv)
150 return -ENOMEM;
151
152 priv->gpio_chip = template_chip;
153 priv->gpio_chip.label = "ts4900-gpio";
154 priv->gpio_chip.ngpio = ngpio;
155 priv->gpio_chip.parent = &client->dev;
156 priv->input_bit = (uintptr_t)of_device_get_match_data(&client->dev);
157
158 priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config);
159 if (IS_ERR(priv->regmap)) {
160 ret = PTR_ERR(priv->regmap);
161 dev_err(&client->dev, "Failed to allocate register map: %d\n",
162 ret);
163 return ret;
164 }
165
166 ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv);
167 if (ret < 0) {
168 dev_err(&client->dev, "Unable to register gpiochip\n");
169 return ret;
170 }
171
172 i2c_set_clientdata(client, priv);
173
174 return 0;
175}
176
177static const struct i2c_device_id ts4900_gpio_id_table[] = {
178 { "ts4900-gpio", },
179 { /* sentinel */ }
180};
181MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table);
182
183static struct i2c_driver ts4900_gpio_driver = {
184 .driver = {
185 .name = "ts4900-gpio",
186 .of_match_table = ts4900_gpio_of_match_table,
187 },
188 .probe_new = ts4900_gpio_probe,
189 .id_table = ts4900_gpio_id_table,
190};
191module_i2c_driver(ts4900_gpio_driver);
192
193MODULE_AUTHOR("Technologic Systems");
194MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core");
195MODULE_LICENSE("GPL");
1/*
2 * Digital I/O driver for Technologic Systems I2C FPGA Core
3 *
4 * Copyright (C) 2015 Technologic Systems
5 * Copyright (C) 2016 Savoir-Faire Linux
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
12 * kind, whether expressed or implied; without even the implied warranty
13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License version 2 for more details.
15 */
16
17#include <linux/gpio/driver.h>
18#include <linux/i2c.h>
19#include <linux/of_device.h>
20#include <linux/module.h>
21#include <linux/regmap.h>
22
23#define DEFAULT_PIN_NUMBER 32
24/*
25 * Register bits used by the GPIO device
26 * Some boards, such as TS-7970 do not have a separate input bit
27 */
28#define TS4900_GPIO_OE 0x01
29#define TS4900_GPIO_OUT 0x02
30#define TS4900_GPIO_IN 0x04
31#define TS7970_GPIO_IN 0x02
32
33struct ts4900_gpio_priv {
34 struct regmap *regmap;
35 struct gpio_chip gpio_chip;
36 unsigned int input_bit;
37};
38
39static int ts4900_gpio_get_direction(struct gpio_chip *chip,
40 unsigned int offset)
41{
42 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
43 unsigned int reg;
44
45 regmap_read(priv->regmap, offset, ®);
46
47 return !(reg & TS4900_GPIO_OE);
48}
49
50static int ts4900_gpio_direction_input(struct gpio_chip *chip,
51 unsigned int offset)
52{
53 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
54
55 /*
56 * This will clear the output enable bit, the other bits are
57 * dontcare when this is cleared
58 */
59 return regmap_write(priv->regmap, offset, 0);
60}
61
62static int ts4900_gpio_direction_output(struct gpio_chip *chip,
63 unsigned int offset, int value)
64{
65 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
66 int ret;
67
68 if (value)
69 ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE |
70 TS4900_GPIO_OUT);
71 else
72 ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE);
73
74 return ret;
75}
76
77static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset)
78{
79 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
80 unsigned int reg;
81
82 regmap_read(priv->regmap, offset, ®);
83
84 return !!(reg & priv->input_bit);
85}
86
87static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset,
88 int value)
89{
90 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
91
92 if (value)
93 regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT,
94 TS4900_GPIO_OUT);
95 else
96 regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0);
97}
98
99static const struct regmap_config ts4900_regmap_config = {
100 .reg_bits = 16,
101 .val_bits = 8,
102};
103
104static const struct gpio_chip template_chip = {
105 .label = "ts4900-gpio",
106 .owner = THIS_MODULE,
107 .get_direction = ts4900_gpio_get_direction,
108 .direction_input = ts4900_gpio_direction_input,
109 .direction_output = ts4900_gpio_direction_output,
110 .get = ts4900_gpio_get,
111 .set = ts4900_gpio_set,
112 .base = -1,
113 .can_sleep = true,
114};
115
116static const struct of_device_id ts4900_gpio_of_match_table[] = {
117 {
118 .compatible = "technologic,ts4900-gpio",
119 .data = (void *)TS4900_GPIO_IN,
120 }, {
121 .compatible = "technologic,ts7970-gpio",
122 .data = (void *)TS7970_GPIO_IN,
123 },
124 { /* sentinel */ },
125};
126MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table);
127
128static int ts4900_gpio_probe(struct i2c_client *client,
129 const struct i2c_device_id *id)
130{
131 const struct of_device_id *match;
132 struct ts4900_gpio_priv *priv;
133 u32 ngpio;
134 int ret;
135
136 match = of_match_device(ts4900_gpio_of_match_table, &client->dev);
137 if (!match)
138 return -EINVAL;
139
140 if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio))
141 ngpio = DEFAULT_PIN_NUMBER;
142
143 priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
144 if (!priv)
145 return -ENOMEM;
146
147 priv->gpio_chip = template_chip;
148 priv->gpio_chip.label = "ts4900-gpio";
149 priv->gpio_chip.ngpio = ngpio;
150 priv->gpio_chip.parent = &client->dev;
151 priv->input_bit = (uintptr_t)match->data;
152
153 priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config);
154 if (IS_ERR(priv->regmap)) {
155 ret = PTR_ERR(priv->regmap);
156 dev_err(&client->dev, "Failed to allocate register map: %d\n",
157 ret);
158 return ret;
159 }
160
161 ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv);
162 if (ret < 0) {
163 dev_err(&client->dev, "Unable to register gpiochip\n");
164 return ret;
165 }
166
167 i2c_set_clientdata(client, priv);
168
169 return 0;
170}
171
172static const struct i2c_device_id ts4900_gpio_id_table[] = {
173 { "ts4900-gpio", },
174 { /* sentinel */ }
175};
176MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table);
177
178static struct i2c_driver ts4900_gpio_driver = {
179 .driver = {
180 .name = "ts4900-gpio",
181 .of_match_table = ts4900_gpio_of_match_table,
182 },
183 .probe = ts4900_gpio_probe,
184 .id_table = ts4900_gpio_id_table,
185};
186module_i2c_driver(ts4900_gpio_driver);
187
188MODULE_AUTHOR("Technologic Systems");
189MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core");
190MODULE_LICENSE("GPL");