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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/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 spi_set_drvdata(spi, chip);
131
132 chip->gpio_chip.label = spi->modalias;
133 chip->gpio_chip.direction_output = gen_74x164_direction_output;
134 chip->gpio_chip.get = gen_74x164_get_value;
135 chip->gpio_chip.set = gen_74x164_set_value;
136 chip->gpio_chip.set_multiple = gen_74x164_set_multiple;
137 chip->gpio_chip.base = -1;
138
139 chip->registers = nregs;
140 chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers;
141
142 chip->gpio_chip.can_sleep = true;
143 chip->gpio_chip.parent = &spi->dev;
144 chip->gpio_chip.owner = THIS_MODULE;
145
146 ret = devm_mutex_init(&spi->dev, &chip->lock);
147 if (ret)
148 return ret;
149
150 ret = __gen_74x164_write_config(chip);
151 if (ret)
152 return dev_err_probe(&spi->dev, ret, "Config write failed\n");
153
154 gpiod_set_value_cansleep(chip->gpiod_oe, 1);
155
156 return devm_gpiochip_add_data(&spi->dev, &chip->gpio_chip, chip);
157}
158
159static void gen_74x164_remove(struct spi_device *spi)
160{
161 struct gen_74x164_chip *chip = spi_get_drvdata(spi);
162
163 gpiod_set_value_cansleep(chip->gpiod_oe, 0);
164}
165
166static const struct spi_device_id gen_74x164_spi_ids[] = {
167 { .name = "74hc595" },
168 { .name = "74lvc594" },
169 {},
170};
171MODULE_DEVICE_TABLE(spi, gen_74x164_spi_ids);
172
173static const struct of_device_id gen_74x164_dt_ids[] = {
174 { .compatible = "fairchild,74hc595" },
175 { .compatible = "nxp,74lvc594" },
176 {},
177};
178MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids);
179
180static struct spi_driver gen_74x164_driver = {
181 .driver = {
182 .name = "74x164",
183 .of_match_table = gen_74x164_dt_ids,
184 },
185 .probe = gen_74x164_probe,
186 .remove = gen_74x164_remove,
187 .id_table = gen_74x164_spi_ids,
188};
189module_spi_driver(gen_74x164_driver);
190
191MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
192MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
193MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
194MODULE_LICENSE("GPL v2");