This source file includes following definitions.
- __gen_74x164_write_config
- gen_74x164_get_value
- gen_74x164_set_value
- gen_74x164_set_multiple
- gen_74x164_direction_output
- gen_74x164_probe
- gen_74x164_remove
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9 #include <linux/gpio/consumer.h>
10 #include <linux/gpio/driver.h>
11 #include <linux/module.h>
12 #include <linux/mutex.h>
13 #include <linux/property.h>
14 #include <linux/slab.h>
15 #include <linux/spi/spi.h>
16
17 #define GEN_74X164_NUMBER_GPIOS 8
18
19 struct gen_74x164_chip {
20 struct gpio_chip gpio_chip;
21 struct mutex lock;
22 struct gpio_desc *gpiod_oe;
23 u32 registers;
24
25
26
27
28
29
30
31 u8 buffer[];
32 };
33
34 static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
35 {
36 return spi_write(to_spi_device(chip->gpio_chip.parent), chip->buffer,
37 chip->registers);
38 }
39
40 static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
41 {
42 struct gen_74x164_chip *chip = gpiochip_get_data(gc);
43 u8 bank = chip->registers - 1 - offset / 8;
44 u8 pin = offset % 8;
45 int ret;
46
47 mutex_lock(&chip->lock);
48 ret = (chip->buffer[bank] >> pin) & 0x1;
49 mutex_unlock(&chip->lock);
50
51 return ret;
52 }
53
54 static void gen_74x164_set_value(struct gpio_chip *gc,
55 unsigned offset, int val)
56 {
57 struct gen_74x164_chip *chip = gpiochip_get_data(gc);
58 u8 bank = chip->registers - 1 - offset / 8;
59 u8 pin = offset % 8;
60
61 mutex_lock(&chip->lock);
62 if (val)
63 chip->buffer[bank] |= (1 << pin);
64 else
65 chip->buffer[bank] &= ~(1 << pin);
66
67 __gen_74x164_write_config(chip);
68 mutex_unlock(&chip->lock);
69 }
70
71 static void gen_74x164_set_multiple(struct gpio_chip *gc, unsigned long *mask,
72 unsigned long *bits)
73 {
74 struct gen_74x164_chip *chip = gpiochip_get_data(gc);
75 unsigned int i, idx, shift;
76 u8 bank, bankmask;
77
78 mutex_lock(&chip->lock);
79 for (i = 0, bank = chip->registers - 1; i < chip->registers;
80 i++, bank--) {
81 idx = i / sizeof(*mask);
82 shift = i % sizeof(*mask) * BITS_PER_BYTE;
83 bankmask = mask[idx] >> shift;
84 if (!bankmask)
85 continue;
86
87 chip->buffer[bank] &= ~bankmask;
88 chip->buffer[bank] |= bankmask & (bits[idx] >> shift);
89 }
90 __gen_74x164_write_config(chip);
91 mutex_unlock(&chip->lock);
92 }
93
94 static int gen_74x164_direction_output(struct gpio_chip *gc,
95 unsigned offset, int val)
96 {
97 gen_74x164_set_value(gc, offset, val);
98 return 0;
99 }
100
101 static int gen_74x164_probe(struct spi_device *spi)
102 {
103 struct gen_74x164_chip *chip;
104 u32 nregs;
105 int ret;
106
107
108
109
110 spi->bits_per_word = 8;
111
112 ret = spi_setup(spi);
113 if (ret < 0)
114 return ret;
115
116 ret = device_property_read_u32(&spi->dev, "registers-number", &nregs);
117 if (ret) {
118 dev_err(&spi->dev, "Missing 'registers-number' property.\n");
119 return -EINVAL;
120 }
121
122 chip = devm_kzalloc(&spi->dev, sizeof(*chip) + nregs, GFP_KERNEL);
123 if (!chip)
124 return -ENOMEM;
125
126 chip->gpiod_oe = devm_gpiod_get_optional(&spi->dev, "enable",
127 GPIOD_OUT_LOW);
128 if (IS_ERR(chip->gpiod_oe))
129 return PTR_ERR(chip->gpiod_oe);
130
131 gpiod_set_value_cansleep(chip->gpiod_oe, 1);
132
133 spi_set_drvdata(spi, chip);
134
135 chip->gpio_chip.label = spi->modalias;
136 chip->gpio_chip.direction_output = gen_74x164_direction_output;
137 chip->gpio_chip.get = gen_74x164_get_value;
138 chip->gpio_chip.set = gen_74x164_set_value;
139 chip->gpio_chip.set_multiple = gen_74x164_set_multiple;
140 chip->gpio_chip.base = -1;
141
142 chip->registers = nregs;
143 chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers;
144
145 chip->gpio_chip.can_sleep = true;
146 chip->gpio_chip.parent = &spi->dev;
147 chip->gpio_chip.owner = THIS_MODULE;
148
149 mutex_init(&chip->lock);
150
151 ret = __gen_74x164_write_config(chip);
152 if (ret) {
153 dev_err(&spi->dev, "Failed writing: %d\n", ret);
154 goto exit_destroy;
155 }
156
157 ret = gpiochip_add_data(&chip->gpio_chip, chip);
158 if (!ret)
159 return 0;
160
161 exit_destroy:
162 mutex_destroy(&chip->lock);
163
164 return ret;
165 }
166
167 static int gen_74x164_remove(struct spi_device *spi)
168 {
169 struct gen_74x164_chip *chip = spi_get_drvdata(spi);
170
171 gpiod_set_value_cansleep(chip->gpiod_oe, 0);
172 gpiochip_remove(&chip->gpio_chip);
173 mutex_destroy(&chip->lock);
174
175 return 0;
176 }
177
178 static const struct of_device_id gen_74x164_dt_ids[] = {
179 { .compatible = "fairchild,74hc595" },
180 { .compatible = "nxp,74lvc594" },
181 {},
182 };
183 MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids);
184
185 static struct spi_driver gen_74x164_driver = {
186 .driver = {
187 .name = "74x164",
188 .of_match_table = gen_74x164_dt_ids,
189 },
190 .probe = gen_74x164_probe,
191 .remove = gen_74x164_remove,
192 };
193 module_spi_driver(gen_74x164_driver);
194
195 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
196 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
197 MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
198 MODULE_LICENSE("GPL v2");