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9c668632 LQ |
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 | ||
33 | struct ts4900_gpio_priv { | |
34 | struct regmap *regmap; | |
35 | struct gpio_chip gpio_chip; | |
36 | unsigned int input_bit; | |
37 | }; | |
38 | ||
39 | static 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 | ||
50 | static 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 | ||
62 | static 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 | ||
77 | static 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 | ||
87 | static 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 | ||
99 | static const struct regmap_config ts4900_regmap_config = { | |
100 | .reg_bits = 16, | |
101 | .val_bits = 8, | |
102 | }; | |
103 | ||
e35b5ab0 | 104 | static const struct gpio_chip template_chip = { |
9c668632 LQ |
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 | ||
116 | static 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 | }; | |
126 | MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table); | |
127 | ||
128 | static int ts4900_gpio_probe(struct i2c_client *client, | |
129 | const struct i2c_device_id *id) | |
130 | { | |
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131 | struct ts4900_gpio_priv *priv; |
132 | u32 ngpio; | |
133 | int ret; | |
134 | ||
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135 | if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio)) |
136 | ngpio = DEFAULT_PIN_NUMBER; | |
137 | ||
138 | priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); | |
139 | if (!priv) | |
140 | return -ENOMEM; | |
141 | ||
142 | priv->gpio_chip = template_chip; | |
143 | priv->gpio_chip.label = "ts4900-gpio"; | |
144 | priv->gpio_chip.ngpio = ngpio; | |
145 | priv->gpio_chip.parent = &client->dev; | |
81317c5a | 146 | priv->input_bit = (uintptr_t)of_device_get_match_data(&client->dev); |
9c668632 LQ |
147 | |
148 | priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config); | |
149 | if (IS_ERR(priv->regmap)) { | |
150 | ret = PTR_ERR(priv->regmap); | |
151 | dev_err(&client->dev, "Failed to allocate register map: %d\n", | |
152 | ret); | |
153 | return ret; | |
154 | } | |
155 | ||
156 | ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv); | |
157 | if (ret < 0) { | |
158 | dev_err(&client->dev, "Unable to register gpiochip\n"); | |
159 | return ret; | |
160 | } | |
161 | ||
162 | i2c_set_clientdata(client, priv); | |
163 | ||
164 | return 0; | |
165 | } | |
166 | ||
167 | static const struct i2c_device_id ts4900_gpio_id_table[] = { | |
168 | { "ts4900-gpio", }, | |
169 | { /* sentinel */ } | |
170 | }; | |
171 | MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table); | |
172 | ||
173 | static struct i2c_driver ts4900_gpio_driver = { | |
174 | .driver = { | |
175 | .name = "ts4900-gpio", | |
176 | .of_match_table = ts4900_gpio_of_match_table, | |
177 | }, | |
178 | .probe = ts4900_gpio_probe, | |
179 | .id_table = ts4900_gpio_id_table, | |
180 | }; | |
181 | module_i2c_driver(ts4900_gpio_driver); | |
182 | ||
183 | MODULE_AUTHOR("Technologic Systems"); | |
184 | MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core"); | |
185 | MODULE_LICENSE("GPL"); |