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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/bitops.h>
10#include <linux/gpio/consumer.h>
11#include <linux/gpio/driver.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/property.h>
15#include <linux/slab.h>
16#include <linux/spi/spi.h>
17
18#define GEN_74X164_NUMBER_GPIOS 8
19
20struct gen_74x164_chip {
21 struct gpio_chip gpio_chip;
22 struct mutex lock;
23 struct gpio_desc *gpiod_oe;
24 u32 registers;
25 /*
26 * Since the registers are chained, every byte sent will make
27 * the previous byte shift to the next register in the
28 * chain. Thus, the first byte sent will end up in the last
29 * register at the end of the transfer. So, to have a logical
30 * numbering, store the bytes in reverse order.
31 */
32 u8 buffer[];
33};
34
35static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
36{
37 return spi_write(to_spi_device(chip->gpio_chip.parent), chip->buffer,
38 chip->registers);
39}
40
41static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
42{
43 struct gen_74x164_chip *chip = gpiochip_get_data(gc);
44 u8 bank = chip->registers - 1 - offset / 8;
45 u8 pin = offset % 8;
46 int ret;
47
48 mutex_lock(&chip->lock);
49 ret = (chip->buffer[bank] >> pin) & 0x1;
50 mutex_unlock(&chip->lock);
51
52 return ret;
53}
54
55static void gen_74x164_set_value(struct gpio_chip *gc,
56 unsigned offset, int val)
57{
58 struct gen_74x164_chip *chip = gpiochip_get_data(gc);
59 u8 bank = chip->registers - 1 - offset / 8;
60 u8 pin = offset % 8;
61
62 mutex_lock(&chip->lock);
63 if (val)
64 chip->buffer[bank] |= (1 << pin);
65 else
66 chip->buffer[bank] &= ~(1 << pin);
67
68 __gen_74x164_write_config(chip);
69 mutex_unlock(&chip->lock);
70}
71
72static void gen_74x164_set_multiple(struct gpio_chip *gc, unsigned long *mask,
73 unsigned long *bits)
74{
75 struct gen_74x164_chip *chip = gpiochip_get_data(gc);
76 unsigned long offset;
77 unsigned long bankmask;
78 size_t bank;
79 unsigned long bitmask;
80
81 mutex_lock(&chip->lock);
82 for_each_set_clump8(offset, bankmask, mask, chip->registers * 8) {
83 bank = chip->registers - 1 - offset / 8;
84 bitmask = bitmap_get_value8(bits, offset) & bankmask;
85
86 chip->buffer[bank] &= ~bankmask;
87 chip->buffer[bank] |= bitmask;
88 }
89 __gen_74x164_write_config(chip);
90 mutex_unlock(&chip->lock);
91}
92
93static int gen_74x164_direction_output(struct gpio_chip *gc,
94 unsigned offset, int val)
95{
96 gen_74x164_set_value(gc, offset, val);
97 return 0;
98}
99
100static int gen_74x164_probe(struct spi_device *spi)
101{
102 struct gen_74x164_chip *chip;
103 u32 nregs;
104 int ret;
105
106 /*
107 * bits_per_word cannot be configured in platform data
108 */
109 spi->bits_per_word = 8;
110
111 ret = spi_setup(spi);
112 if (ret < 0)
113 return ret;
114
115 ret = device_property_read_u32(&spi->dev, "registers-number", &nregs);
116 if (ret) {
117 dev_err(&spi->dev, "Missing 'registers-number' property.\n");
118 return -EINVAL;
119 }
120
121 chip = devm_kzalloc(&spi->dev, sizeof(*chip) + nregs, GFP_KERNEL);
122 if (!chip)
123 return -ENOMEM;
124
125 chip->gpiod_oe = devm_gpiod_get_optional(&spi->dev, "enable",
126 GPIOD_OUT_LOW);
127 if (IS_ERR(chip->gpiod_oe))
128 return PTR_ERR(chip->gpiod_oe);
129
130 gpiod_set_value_cansleep(chip->gpiod_oe, 1);
131
132 spi_set_drvdata(spi, chip);
133
134 chip->gpio_chip.label = spi->modalias;
135 chip->gpio_chip.direction_output = gen_74x164_direction_output;
136 chip->gpio_chip.get = gen_74x164_get_value;
137 chip->gpio_chip.set = gen_74x164_set_value;
138 chip->gpio_chip.set_multiple = gen_74x164_set_multiple;
139 chip->gpio_chip.base = -1;
140
141 chip->registers = nregs;
142 chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers;
143
144 chip->gpio_chip.can_sleep = true;
145 chip->gpio_chip.parent = &spi->dev;
146 chip->gpio_chip.owner = THIS_MODULE;
147
148 mutex_init(&chip->lock);
149
150 ret = __gen_74x164_write_config(chip);
151 if (ret) {
152 dev_err(&spi->dev, "Failed writing: %d\n", ret);
153 goto exit_destroy;
154 }
155
156 ret = gpiochip_add_data(&chip->gpio_chip, chip);
157 if (!ret)
158 return 0;
159
160exit_destroy:
161 mutex_destroy(&chip->lock);
162
163 return ret;
164}
165
166static void gen_74x164_remove(struct spi_device *spi)
167{
168 struct gen_74x164_chip *chip = spi_get_drvdata(spi);
169
170 gpiod_set_value_cansleep(chip->gpiod_oe, 0);
171 gpiochip_remove(&chip->gpio_chip);
172 mutex_destroy(&chip->lock);
173}
174
175static const struct spi_device_id gen_74x164_spi_ids[] = {
176 { .name = "74hc595" },
177 { .name = "74lvc594" },
178 {},
179};
180MODULE_DEVICE_TABLE(spi, gen_74x164_spi_ids);
181
182static const struct of_device_id gen_74x164_dt_ids[] = {
183 { .compatible = "fairchild,74hc595" },
184 { .compatible = "nxp,74lvc594" },
185 {},
186};
187MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids);
188
189static struct spi_driver gen_74x164_driver = {
190 .driver = {
191 .name = "74x164",
192 .of_match_table = gen_74x164_dt_ids,
193 },
194 .probe = gen_74x164_probe,
195 .remove = gen_74x164_remove,
196 .id_table = gen_74x164_spi_ids,
197};
198module_spi_driver(gen_74x164_driver);
199
200MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
201MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
202MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
203MODULE_LICENSE("GPL v2");
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#include <linux/module.h>
19
20struct gen_74x164_chip {
21 struct spi_device *spi;
22 struct gpio_chip gpio_chip;
23 struct mutex lock;
24 u8 port_config;
25};
26
27static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc)
28{
29 return container_of(gc, struct gen_74x164_chip, gpio_chip);
30}
31
32static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
33{
34 return spi_write(chip->spi,
35 &chip->port_config, sizeof(chip->port_config));
36}
37
38static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
39{
40 struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
41 int ret;
42
43 mutex_lock(&chip->lock);
44 ret = (chip->port_config >> offset) & 0x1;
45 mutex_unlock(&chip->lock);
46
47 return ret;
48}
49
50static void gen_74x164_set_value(struct gpio_chip *gc,
51 unsigned offset, int val)
52{
53 struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
54
55 mutex_lock(&chip->lock);
56 if (val)
57 chip->port_config |= (1 << offset);
58 else
59 chip->port_config &= ~(1 << offset);
60
61 __gen_74x164_write_config(chip);
62 mutex_unlock(&chip->lock);
63}
64
65static int gen_74x164_direction_output(struct gpio_chip *gc,
66 unsigned offset, int val)
67{
68 gen_74x164_set_value(gc, offset, val);
69 return 0;
70}
71
72static int __devinit gen_74x164_probe(struct spi_device *spi)
73{
74 struct gen_74x164_chip *chip;
75 struct gen_74x164_chip_platform_data *pdata;
76 int ret;
77
78 pdata = spi->dev.platform_data;
79 if (!pdata || !pdata->base) {
80 dev_dbg(&spi->dev, "incorrect or missing platform data\n");
81 return -EINVAL;
82 }
83
84 /*
85 * bits_per_word cannot be configured in platform data
86 */
87 spi->bits_per_word = 8;
88
89 ret = spi_setup(spi);
90 if (ret < 0)
91 return ret;
92
93 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
94 if (!chip)
95 return -ENOMEM;
96
97 mutex_init(&chip->lock);
98
99 dev_set_drvdata(&spi->dev, chip);
100
101 chip->spi = spi;
102
103 chip->gpio_chip.label = spi->modalias;
104 chip->gpio_chip.direction_output = gen_74x164_direction_output;
105 chip->gpio_chip.get = gen_74x164_get_value;
106 chip->gpio_chip.set = gen_74x164_set_value;
107 chip->gpio_chip.base = pdata->base;
108 chip->gpio_chip.ngpio = 8;
109 chip->gpio_chip.can_sleep = 1;
110 chip->gpio_chip.dev = &spi->dev;
111 chip->gpio_chip.owner = THIS_MODULE;
112
113 ret = __gen_74x164_write_config(chip);
114 if (ret) {
115 dev_err(&spi->dev, "Failed writing: %d\n", ret);
116 goto exit_destroy;
117 }
118
119 ret = gpiochip_add(&chip->gpio_chip);
120 if (ret)
121 goto exit_destroy;
122
123 return ret;
124
125exit_destroy:
126 dev_set_drvdata(&spi->dev, NULL);
127 mutex_destroy(&chip->lock);
128 kfree(chip);
129 return ret;
130}
131
132static int __devexit gen_74x164_remove(struct spi_device *spi)
133{
134 struct gen_74x164_chip *chip;
135 int ret;
136
137 chip = dev_get_drvdata(&spi->dev);
138 if (chip == NULL)
139 return -ENODEV;
140
141 dev_set_drvdata(&spi->dev, NULL);
142
143 ret = gpiochip_remove(&chip->gpio_chip);
144 if (!ret) {
145 mutex_destroy(&chip->lock);
146 kfree(chip);
147 } else
148 dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
149 ret);
150
151 return ret;
152}
153
154static struct spi_driver gen_74x164_driver = {
155 .driver = {
156 .name = "74x164",
157 .owner = THIS_MODULE,
158 },
159 .probe = gen_74x164_probe,
160 .remove = __devexit_p(gen_74x164_remove),
161};
162
163static int __init gen_74x164_init(void)
164{
165 return spi_register_driver(&gen_74x164_driver);
166}
167subsys_initcall(gen_74x164_init);
168
169static void __exit gen_74x164_exit(void)
170{
171 spi_unregister_driver(&gen_74x164_driver);
172}
173module_exit(gen_74x164_exit);
174
175MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
176MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
177MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
178MODULE_LICENSE("GPL v2");