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Miguel Gaioead6db082010-10-27 15:33:18 -07001/*
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>
Miguel Gaioead6db082010-10-27 15:33:18 -070015#include <linux/gpio.h>
Maxime Ripard20bc4d52012-09-10 22:35:39 +020016#include <linux/of_gpio.h>
Miguel Gaioead6db082010-10-27 15:33:18 -070017#include <linux/slab.h>
Paul Gortmakerbb207ef2011-07-03 13:38:09 -040018#include <linux/module.h>
Miguel Gaioead6db082010-10-27 15:33:18 -070019
Maxime Ripard20bc4d52012-09-10 22:35:39 +020020#define GEN_74X164_NUMBER_GPIOS 8
21
Miguel Gaioead6db082010-10-27 15:33:18 -070022struct gen_74x164_chip {
Maxime Ripard20bc4d52012-09-10 22:35:39 +020023 u8 *buffer;
Miguel Gaioead6db082010-10-27 15:33:18 -070024 struct gpio_chip gpio_chip;
25 struct mutex lock;
Maxime Ripard20bc4d52012-09-10 22:35:39 +020026 u32 registers;
Miguel Gaioead6db082010-10-27 15:33:18 -070027};
28
Linus Walleij12610be2011-06-13 10:47:15 +020029static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc)
Miguel Gaioead6db082010-10-27 15:33:18 -070030{
31 return container_of(gc, struct gen_74x164_chip, gpio_chip);
32}
33
34static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
35{
Alexander Shiyanbcc05622013-12-07 14:08:23 +040036 struct spi_device *spi = to_spi_device(chip->gpio_chip.dev);
Maxime Ripard20bc4d52012-09-10 22:35:39 +020037 struct spi_message message;
38 struct spi_transfer *msg_buf;
39 int i, ret = 0;
40
41 msg_buf = kzalloc(chip->registers * sizeof(struct spi_transfer),
42 GFP_KERNEL);
43 if (!msg_buf)
44 return -ENOMEM;
45
46 spi_message_init(&message);
47
48 /*
49 * Since the registers are chained, every byte sent will make
50 * the previous byte shift to the next register in the
51 * chain. Thus, the first byte send will end up in the last
52 * register at the end of the transfer. So, to have a logical
53 * numbering, send the bytes in reverse order so that the last
54 * byte of the buffer will end up in the last register.
55 */
56 for (i = chip->registers - 1; i >= 0; i--) {
Alexander Shiyanbcc05622013-12-07 14:08:23 +040057 msg_buf[i].tx_buf = chip->buffer + i;
Maxime Ripard20bc4d52012-09-10 22:35:39 +020058 msg_buf[i].len = sizeof(u8);
59 spi_message_add_tail(msg_buf + i, &message);
60 }
61
Alexander Shiyanbcc05622013-12-07 14:08:23 +040062 ret = spi_sync(spi, &message);
Maxime Ripard20bc4d52012-09-10 22:35:39 +020063
64 kfree(msg_buf);
65
66 return ret;
Miguel Gaioead6db082010-10-27 15:33:18 -070067}
68
Miguel Gaioead6db082010-10-27 15:33:18 -070069static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
70{
Linus Walleij12610be2011-06-13 10:47:15 +020071 struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
Maxime Ripard20bc4d52012-09-10 22:35:39 +020072 u8 bank = offset / 8;
73 u8 pin = offset % 8;
Miguel Gaioead6db082010-10-27 15:33:18 -070074 int ret;
75
76 mutex_lock(&chip->lock);
Maxime Ripard20bc4d52012-09-10 22:35:39 +020077 ret = (chip->buffer[bank] >> pin) & 0x1;
Miguel Gaioead6db082010-10-27 15:33:18 -070078 mutex_unlock(&chip->lock);
79
80 return ret;
81}
82
83static void gen_74x164_set_value(struct gpio_chip *gc,
84 unsigned offset, int val)
85{
Linus Walleij12610be2011-06-13 10:47:15 +020086 struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
Maxime Ripard20bc4d52012-09-10 22:35:39 +020087 u8 bank = offset / 8;
88 u8 pin = offset % 8;
Miguel Gaioead6db082010-10-27 15:33:18 -070089
90 mutex_lock(&chip->lock);
91 if (val)
Maxime Ripard20bc4d52012-09-10 22:35:39 +020092 chip->buffer[bank] |= (1 << pin);
Miguel Gaioead6db082010-10-27 15:33:18 -070093 else
Maxime Ripard20bc4d52012-09-10 22:35:39 +020094 chip->buffer[bank] &= ~(1 << pin);
Miguel Gaioead6db082010-10-27 15:33:18 -070095
96 __gen_74x164_write_config(chip);
97 mutex_unlock(&chip->lock);
98}
99
H Hartley Sweetena3cc68c2011-05-27 16:35:59 -0700100static int gen_74x164_direction_output(struct gpio_chip *gc,
101 unsigned offset, int val)
102{
103 gen_74x164_set_value(gc, offset, val);
104 return 0;
105}
106
Bill Pemberton38363092012-11-19 13:22:34 -0500107static int gen_74x164_probe(struct spi_device *spi)
Miguel Gaioead6db082010-10-27 15:33:18 -0700108{
109 struct gen_74x164_chip *chip;
Miguel Gaioead6db082010-10-27 15:33:18 -0700110 int ret;
111
Miguel Gaioead6db082010-10-27 15:33:18 -0700112 /*
113 * bits_per_word cannot be configured in platform data
114 */
115 spi->bits_per_word = 8;
116
117 ret = spi_setup(spi);
118 if (ret < 0)
119 return ret;
120
Maxime Ripard72eac302012-09-05 10:40:51 +0200121 chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL);
Miguel Gaioead6db082010-10-27 15:33:18 -0700122 if (!chip)
123 return -ENOMEM;
124
Jingoo Han6c0cf422013-03-15 18:17:18 +0900125 spi_set_drvdata(spi, chip);
Miguel Gaioead6db082010-10-27 15:33:18 -0700126
H Hartley Sweetena3cc68c2011-05-27 16:35:59 -0700127 chip->gpio_chip.label = spi->modalias;
128 chip->gpio_chip.direction_output = gen_74x164_direction_output;
Miguel Gaioead6db082010-10-27 15:33:18 -0700129 chip->gpio_chip.get = gen_74x164_get_value;
130 chip->gpio_chip.set = gen_74x164_set_value;
Alexander Shiyan61e73802013-12-07 14:08:22 +0400131 chip->gpio_chip.base = -1;
Maxime Ripard20bc4d52012-09-10 22:35:39 +0200132
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400133 if (of_property_read_u32(spi->dev.of_node, "registers-number",
134 &chip->registers)) {
135 dev_err(&spi->dev,
136 "Missing registers-number property in the DT.\n");
137 return -EINVAL;
Maxime Ripard20bc4d52012-09-10 22:35:39 +0200138 }
139
140 chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers;
Roland Stiggea48221a2012-10-16 15:24:01 +0200141 chip->buffer = devm_kzalloc(&spi->dev, chip->registers, GFP_KERNEL);
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400142 if (!chip->buffer)
143 return -ENOMEM;
Maxime Ripard20bc4d52012-09-10 22:35:39 +0200144
Linus Walleij9fb1f392013-12-04 14:42:46 +0100145 chip->gpio_chip.can_sleep = true;
Miguel Gaioead6db082010-10-27 15:33:18 -0700146 chip->gpio_chip.dev = &spi->dev;
147 chip->gpio_chip.owner = THIS_MODULE;
148
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400149 mutex_init(&chip->lock);
150
Miguel Gaioead6db082010-10-27 15:33:18 -0700151 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(&chip->gpio_chip);
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400158 if (!ret)
159 return 0;
Miguel Gaioead6db082010-10-27 15:33:18 -0700160
161exit_destroy:
Miguel Gaioead6db082010-10-27 15:33:18 -0700162 mutex_destroy(&chip->lock);
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400163
Miguel Gaioead6db082010-10-27 15:33:18 -0700164 return ret;
165}
166
Bill Pemberton206210c2012-11-19 13:25:50 -0500167static int gen_74x164_remove(struct spi_device *spi)
Miguel Gaioead6db082010-10-27 15:33:18 -0700168{
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400169 struct gen_74x164_chip *chip = spi_get_drvdata(spi);
Miguel Gaioead6db082010-10-27 15:33:18 -0700170 int ret;
171
Miguel Gaioead6db082010-10-27 15:33:18 -0700172 ret = gpiochip_remove(&chip->gpio_chip);
Maxime Ripard72eac302012-09-05 10:40:51 +0200173 if (!ret)
Miguel Gaioead6db082010-10-27 15:33:18 -0700174 mutex_destroy(&chip->lock);
Miguel Gaioead6db082010-10-27 15:33:18 -0700175
176 return ret;
177}
178
Maxime Ripard0a90a9f2012-09-07 14:18:13 +0200179static const struct of_device_id gen_74x164_dt_ids[] = {
180 { .compatible = "fairchild,74hc595" },
181 {},
182};
183MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids);
184
Miguel Gaioead6db082010-10-27 15:33:18 -0700185static struct spi_driver gen_74x164_driver = {
186 .driver = {
H Hartley Sweetena3cc68c2011-05-27 16:35:59 -0700187 .name = "74x164",
Miguel Gaioead6db082010-10-27 15:33:18 -0700188 .owner = THIS_MODULE,
Sachin Kamat187a53a2013-09-19 17:28:08 +0530189 .of_match_table = gen_74x164_dt_ids,
Miguel Gaioead6db082010-10-27 15:33:18 -0700190 },
191 .probe = gen_74x164_probe,
Bill Pemberton8283c4f2012-11-19 13:20:08 -0500192 .remove = gen_74x164_remove,
Miguel Gaioead6db082010-10-27 15:33:18 -0700193};
Maxime Ripardab3b8782012-09-05 10:40:50 +0200194module_spi_driver(gen_74x164_driver);
Miguel Gaioead6db082010-10-27 15:33:18 -0700195
196MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
197MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
198MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
199MODULE_LICENSE("GPL v2");