1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * TI/National Semiconductor LP3943 GPIO driver
4 *
5 * Copyright 2013 Texas Instruments
6 *
7 * Author: Milo Kim <milo.kim@ti.com>
8 */
9
10 #include <linux/bitops.h>
11 #include <linux/err.h>
12 #include <linux/gpio/driver.h>
13 #include <linux/i2c.h>
14 #include <linux/mfd/lp3943.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18
19 enum lp3943_gpios {
20 LP3943_GPIO1,
21 LP3943_GPIO2,
22 LP3943_GPIO3,
23 LP3943_GPIO4,
24 LP3943_GPIO5,
25 LP3943_GPIO6,
26 LP3943_GPIO7,
27 LP3943_GPIO8,
28 LP3943_GPIO9,
29 LP3943_GPIO10,
30 LP3943_GPIO11,
31 LP3943_GPIO12,
32 LP3943_GPIO13,
33 LP3943_GPIO14,
34 LP3943_GPIO15,
35 LP3943_GPIO16,
36 LP3943_MAX_GPIO,
37 };
38
39 struct lp3943_gpio {
40 struct gpio_chip chip;
41 struct lp3943 *lp3943;
42 u16 input_mask; /* 1 = GPIO is input direction, 0 = output */
43 };
44
lp3943_gpio_request(struct gpio_chip * chip,unsigned int offset)45 static int lp3943_gpio_request(struct gpio_chip *chip, unsigned int offset)
46 {
47 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
48 struct lp3943 *lp3943 = lp3943_gpio->lp3943;
49
50 /* Return an error if the pin is already assigned */
51 if (test_and_set_bit(offset, &lp3943->pin_used))
52 return -EBUSY;
53
54 return 0;
55 }
56
lp3943_gpio_free(struct gpio_chip * chip,unsigned int offset)57 static void lp3943_gpio_free(struct gpio_chip *chip, unsigned int offset)
58 {
59 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
60 struct lp3943 *lp3943 = lp3943_gpio->lp3943;
61
62 clear_bit(offset, &lp3943->pin_used);
63 }
64
lp3943_gpio_set_mode(struct lp3943_gpio * lp3943_gpio,u8 offset,u8 val)65 static int lp3943_gpio_set_mode(struct lp3943_gpio *lp3943_gpio, u8 offset,
66 u8 val)
67 {
68 struct lp3943 *lp3943 = lp3943_gpio->lp3943;
69 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
70
71 return lp3943_update_bits(lp3943, mux[offset].reg, mux[offset].mask,
72 val << mux[offset].shift);
73 }
74
lp3943_gpio_direction_input(struct gpio_chip * chip,unsigned int offset)75 static int lp3943_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
76 {
77 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
78
79 lp3943_gpio->input_mask |= BIT(offset);
80
81 return lp3943_gpio_set_mode(lp3943_gpio, offset, LP3943_GPIO_IN);
82 }
83
lp3943_get_gpio_in_status(struct lp3943_gpio * lp3943_gpio,struct gpio_chip * chip,unsigned int offset)84 static int lp3943_get_gpio_in_status(struct lp3943_gpio *lp3943_gpio,
85 struct gpio_chip *chip, unsigned int offset)
86 {
87 u8 addr, read;
88 int err;
89
90 switch (offset) {
91 case LP3943_GPIO1 ... LP3943_GPIO8:
92 addr = LP3943_REG_GPIO_A;
93 break;
94 case LP3943_GPIO9 ... LP3943_GPIO16:
95 addr = LP3943_REG_GPIO_B;
96 offset = offset - 8;
97 break;
98 default:
99 return -EINVAL;
100 }
101
102 err = lp3943_read_byte(lp3943_gpio->lp3943, addr, &read);
103 if (err)
104 return err;
105
106 return !!(read & BIT(offset));
107 }
108
lp3943_get_gpio_out_status(struct lp3943_gpio * lp3943_gpio,struct gpio_chip * chip,unsigned int offset)109 static int lp3943_get_gpio_out_status(struct lp3943_gpio *lp3943_gpio,
110 struct gpio_chip *chip, unsigned int offset)
111 {
112 struct lp3943 *lp3943 = lp3943_gpio->lp3943;
113 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
114 u8 read;
115 int err;
116
117 err = lp3943_read_byte(lp3943, mux[offset].reg, &read);
118 if (err)
119 return err;
120
121 read = (read & mux[offset].mask) >> mux[offset].shift;
122
123 if (read == LP3943_GPIO_OUT_HIGH)
124 return 1;
125 else if (read == LP3943_GPIO_OUT_LOW)
126 return 0;
127 else
128 return -EINVAL;
129 }
130
lp3943_gpio_get(struct gpio_chip * chip,unsigned int offset)131 static int lp3943_gpio_get(struct gpio_chip *chip, unsigned int offset)
132 {
133 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
134
135 /*
136 * Limitation:
137 * LP3943 doesn't have the GPIO direction register. It provides
138 * only input and output status registers.
139 * So, direction info is required to handle the 'get' operation.
140 * This variable is updated whenever the direction is changed and
141 * it is used here.
142 */
143
144 if (lp3943_gpio->input_mask & BIT(offset))
145 return lp3943_get_gpio_in_status(lp3943_gpio, chip, offset);
146 else
147 return lp3943_get_gpio_out_status(lp3943_gpio, chip, offset);
148 }
149
lp3943_gpio_set(struct gpio_chip * chip,unsigned int offset,int value)150 static void lp3943_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
151 {
152 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
153 u8 data;
154
155 if (value)
156 data = LP3943_GPIO_OUT_HIGH;
157 else
158 data = LP3943_GPIO_OUT_LOW;
159
160 lp3943_gpio_set_mode(lp3943_gpio, offset, data);
161 }
162
lp3943_gpio_direction_output(struct gpio_chip * chip,unsigned int offset,int value)163 static int lp3943_gpio_direction_output(struct gpio_chip *chip, unsigned int offset,
164 int value)
165 {
166 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
167
168 lp3943_gpio_set(chip, offset, value);
169 lp3943_gpio->input_mask &= ~BIT(offset);
170
171 return 0;
172 }
173
174 static const struct gpio_chip lp3943_gpio_chip = {
175 .label = "lp3943",
176 .owner = THIS_MODULE,
177 .request = lp3943_gpio_request,
178 .free = lp3943_gpio_free,
179 .direction_input = lp3943_gpio_direction_input,
180 .get = lp3943_gpio_get,
181 .direction_output = lp3943_gpio_direction_output,
182 .set = lp3943_gpio_set,
183 .base = -1,
184 .ngpio = LP3943_MAX_GPIO,
185 .can_sleep = 1,
186 };
187
lp3943_gpio_probe(struct platform_device * pdev)188 static int lp3943_gpio_probe(struct platform_device *pdev)
189 {
190 struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
191 struct lp3943_gpio *lp3943_gpio;
192
193 lp3943_gpio = devm_kzalloc(&pdev->dev, sizeof(*lp3943_gpio),
194 GFP_KERNEL);
195 if (!lp3943_gpio)
196 return -ENOMEM;
197
198 lp3943_gpio->lp3943 = lp3943;
199 lp3943_gpio->chip = lp3943_gpio_chip;
200 lp3943_gpio->chip.parent = &pdev->dev;
201
202 return devm_gpiochip_add_data(&pdev->dev, &lp3943_gpio->chip,
203 lp3943_gpio);
204 }
205
206 static const struct of_device_id lp3943_gpio_of_match[] = {
207 { .compatible = "ti,lp3943-gpio", },
208 { }
209 };
210 MODULE_DEVICE_TABLE(of, lp3943_gpio_of_match);
211
212 static struct platform_driver lp3943_gpio_driver = {
213 .probe = lp3943_gpio_probe,
214 .driver = {
215 .name = "lp3943-gpio",
216 .of_match_table = lp3943_gpio_of_match,
217 },
218 };
219 module_platform_driver(lp3943_gpio_driver);
220
221 MODULE_DESCRIPTION("LP3943 GPIO driver");
222 MODULE_ALIAS("platform:lp3943-gpio");
223 MODULE_AUTHOR("Milo Kim");
224 MODULE_LICENSE("GPL");
225