Loading...
1/*
2 * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
3 *
4 * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
5 * Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/init.h>
13#include <linux/mutex.h>
14#include <linux/spi/spi.h>
15#include <linux/spi/74x164.h>
16#include <linux/gpio.h>
17#include <linux/slab.h>
18
19struct gen_74x164_chip {
20 struct spi_device *spi;
21 struct gpio_chip gpio_chip;
22 struct mutex lock;
23 u8 port_config;
24};
25
26static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc)
27{
28 return container_of(gc, struct gen_74x164_chip, gpio_chip);
29}
30
31static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
32{
33 return spi_write(chip->spi,
34 &chip->port_config, sizeof(chip->port_config));
35}
36
37static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
38{
39 struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
40 int ret;
41
42 mutex_lock(&chip->lock);
43 ret = (chip->port_config >> offset) & 0x1;
44 mutex_unlock(&chip->lock);
45
46 return ret;
47}
48
49static void gen_74x164_set_value(struct gpio_chip *gc,
50 unsigned offset, int val)
51{
52 struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
53
54 mutex_lock(&chip->lock);
55 if (val)
56 chip->port_config |= (1 << offset);
57 else
58 chip->port_config &= ~(1 << offset);
59
60 __gen_74x164_write_config(chip);
61 mutex_unlock(&chip->lock);
62}
63
64static int gen_74x164_direction_output(struct gpio_chip *gc,
65 unsigned offset, int val)
66{
67 gen_74x164_set_value(gc, offset, val);
68 return 0;
69}
70
71static int __devinit gen_74x164_probe(struct spi_device *spi)
72{
73 struct gen_74x164_chip *chip;
74 struct gen_74x164_chip_platform_data *pdata;
75 int ret;
76
77 pdata = spi->dev.platform_data;
78 if (!pdata || !pdata->base) {
79 dev_dbg(&spi->dev, "incorrect or missing platform data\n");
80 return -EINVAL;
81 }
82
83 /*
84 * bits_per_word cannot be configured in platform data
85 */
86 spi->bits_per_word = 8;
87
88 ret = spi_setup(spi);
89 if (ret < 0)
90 return ret;
91
92 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
93 if (!chip)
94 return -ENOMEM;
95
96 mutex_init(&chip->lock);
97
98 dev_set_drvdata(&spi->dev, chip);
99
100 chip->spi = spi;
101
102 chip->gpio_chip.label = spi->modalias;
103 chip->gpio_chip.direction_output = gen_74x164_direction_output;
104 chip->gpio_chip.get = gen_74x164_get_value;
105 chip->gpio_chip.set = gen_74x164_set_value;
106 chip->gpio_chip.base = pdata->base;
107 chip->gpio_chip.ngpio = 8;
108 chip->gpio_chip.can_sleep = 1;
109 chip->gpio_chip.dev = &spi->dev;
110 chip->gpio_chip.owner = THIS_MODULE;
111
112 ret = __gen_74x164_write_config(chip);
113 if (ret) {
114 dev_err(&spi->dev, "Failed writing: %d\n", ret);
115 goto exit_destroy;
116 }
117
118 ret = gpiochip_add(&chip->gpio_chip);
119 if (ret)
120 goto exit_destroy;
121
122 return ret;
123
124exit_destroy:
125 dev_set_drvdata(&spi->dev, NULL);
126 mutex_destroy(&chip->lock);
127 kfree(chip);
128 return ret;
129}
130
131static int __devexit gen_74x164_remove(struct spi_device *spi)
132{
133 struct gen_74x164_chip *chip;
134 int ret;
135
136 chip = dev_get_drvdata(&spi->dev);
137 if (chip == NULL)
138 return -ENODEV;
139
140 dev_set_drvdata(&spi->dev, NULL);
141
142 ret = gpiochip_remove(&chip->gpio_chip);
143 if (!ret) {
144 mutex_destroy(&chip->lock);
145 kfree(chip);
146 } else
147 dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
148 ret);
149
150 return ret;
151}
152
153static struct spi_driver gen_74x164_driver = {
154 .driver = {
155 .name = "74x164",
156 .owner = THIS_MODULE,
157 },
158 .probe = gen_74x164_probe,
159 .remove = __devexit_p(gen_74x164_remove),
160};
161
162static int __init gen_74x164_init(void)
163{
164 return spi_register_driver(&gen_74x164_driver);
165}
166subsys_initcall(gen_74x164_init);
167
168static void __exit gen_74x164_exit(void)
169{
170 spi_unregister_driver(&gen_74x164_driver);
171}
172module_exit(gen_74x164_exit);
173
174MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
175MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
176MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
177MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
4 *
5 * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
6 * Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.com>
7 */
8
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
19struct gen_74x164_chip {
20 struct gpio_chip gpio_chip;
21 struct mutex lock;
22 struct gpio_desc *gpiod_oe;
23 u32 registers;
24 /*
25 * Since the registers are chained, every byte sent will make
26 * the previous byte shift to the next register in the
27 * chain. Thus, the first byte sent will end up in the last
28 * register at the end of the transfer. So, to have a logical
29 * numbering, store the bytes in reverse order.
30 */
31 u8 buffer[];
32};
33
34static 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
40static 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
54static 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
71static 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
94static 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
101static int gen_74x164_probe(struct spi_device *spi)
102{
103 struct gen_74x164_chip *chip;
104 u32 nregs;
105 int ret;
106
107 /*
108 * bits_per_word cannot be configured in platform data
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
161exit_destroy:
162 mutex_destroy(&chip->lock);
163
164 return ret;
165}
166
167static 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
178static const struct of_device_id gen_74x164_dt_ids[] = {
179 { .compatible = "fairchild,74hc595" },
180 { .compatible = "nxp,74lvc594" },
181 {},
182};
183MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids);
184
185static 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};
193module_spi_driver(gen_74x164_driver);
194
195MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
196MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
197MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
198MODULE_LICENSE("GPL v2");