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87ba5bad | 1 | // SPDX-License-Identifier: GPL-2.0 |
9c668632 LQ |
2 | /* |
3 | * Digital I/O driver for Technologic Systems I2C FPGA Core | |
4 | * | |
03fe0035 | 5 | * Copyright (C) 2015, 2018 Technologic Systems |
9c668632 | 6 | * Copyright (C) 2016 Savoir-Faire Linux |
9c668632 LQ |
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 | ||
25 | struct ts4900_gpio_priv { | |
26 | struct regmap *regmap; | |
27 | struct gpio_chip gpio_chip; | |
28 | unsigned int input_bit; | |
29 | }; | |
30 | ||
31 | static 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 | ||
e42615ec MV |
39 | if (reg & TS4900_GPIO_OE) |
40 | return GPIO_LINE_DIRECTION_OUT; | |
41 | ||
42 | return GPIO_LINE_DIRECTION_IN; | |
9c668632 LQ |
43 | } |
44 | ||
45 | static 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 | ||
576892a8 KB |
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. | |
9c668632 | 53 | */ |
03fe0035 | 54 | return regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OE, 0); |
9c668632 LQ |
55 | } |
56 | ||
57 | static 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); | |
03fe0035 | 61 | unsigned int reg; |
9c668632 LQ |
62 | int ret; |
63 | ||
576892a8 KB |
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. | |
03fe0035 MF |
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 | ||
9c668632 LQ |
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 | ||
88 | static 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 | ||
98 | static 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 | ||
110 | static const struct regmap_config ts4900_regmap_config = { | |
111 | .reg_bits = 16, | |
112 | .val_bits = 8, | |
113 | }; | |
114 | ||
e35b5ab0 | 115 | static const struct gpio_chip template_chip = { |
9c668632 LQ |
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 | ||
127 | static 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 | }; | |
137 | MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table); | |
138 | ||
139 | static int ts4900_gpio_probe(struct i2c_client *client, | |
140 | const struct i2c_device_id *id) | |
141 | { | |
9c668632 LQ |
142 | struct ts4900_gpio_priv *priv; |
143 | u32 ngpio; | |
144 | int ret; | |
145 | ||
9c668632 LQ |
146 | if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio)) |
147 | ngpio = DEFAULT_PIN_NUMBER; | |
148 | ||
149 | priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); | |
150 | if (!priv) | |
151 | return -ENOMEM; | |
152 | ||
153 | priv->gpio_chip = template_chip; | |
154 | priv->gpio_chip.label = "ts4900-gpio"; | |
155 | priv->gpio_chip.ngpio = ngpio; | |
156 | priv->gpio_chip.parent = &client->dev; | |
81317c5a | 157 | priv->input_bit = (uintptr_t)of_device_get_match_data(&client->dev); |
9c668632 LQ |
158 | |
159 | priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config); | |
160 | if (IS_ERR(priv->regmap)) { | |
161 | ret = PTR_ERR(priv->regmap); | |
162 | dev_err(&client->dev, "Failed to allocate register map: %d\n", | |
163 | ret); | |
164 | return ret; | |
165 | } | |
166 | ||
167 | ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv); | |
168 | if (ret < 0) { | |
169 | dev_err(&client->dev, "Unable to register gpiochip\n"); | |
170 | return ret; | |
171 | } | |
172 | ||
173 | i2c_set_clientdata(client, priv); | |
174 | ||
175 | return 0; | |
176 | } | |
177 | ||
178 | static const struct i2c_device_id ts4900_gpio_id_table[] = { | |
179 | { "ts4900-gpio", }, | |
180 | { /* sentinel */ } | |
181 | }; | |
182 | MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table); | |
183 | ||
184 | static struct i2c_driver ts4900_gpio_driver = { | |
185 | .driver = { | |
186 | .name = "ts4900-gpio", | |
187 | .of_match_table = ts4900_gpio_of_match_table, | |
188 | }, | |
189 | .probe = ts4900_gpio_probe, | |
190 | .id_table = ts4900_gpio_id_table, | |
191 | }; | |
192 | module_i2c_driver(ts4900_gpio_driver); | |
193 | ||
194 | MODULE_AUTHOR("Technologic Systems"); | |
195 | MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core"); | |
196 | MODULE_LICENSE("GPL"); |