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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 {
Miguel Gaioead6db082010-10-27 15:33:18 -070023 struct gpio_chip gpio_chip;
24 struct mutex lock;
Maxime Ripard20bc4d52012-09-10 22:35:39 +020025 u32 registers;
Geert Uytterhoeven902e7e62015-11-30 15:35:26 +010026 /*
27 * Since the registers are chained, every byte sent will make
28 * the previous byte shift to the next register in the
29 * chain. Thus, the first byte sent will end up in the last
30 * register at the end of the transfer. So, to have a logical
31 * numbering, store the bytes in reverse order.
32 */
Geert Uytterhoeven410f4572015-11-30 15:35:25 +010033 u8 buffer[0];
Miguel Gaioead6db082010-10-27 15:33:18 -070034};
35
Miguel Gaioead6db082010-10-27 15:33:18 -070036static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
37{
Geert Uytterhoeven902e7e62015-11-30 15:35:26 +010038 struct spi_transfer xfer = {
39 .tx_buf = chip->buffer,
40 .len = chip->registers,
41 };
Maxime Ripard20bc4d52012-09-10 22:35:39 +020042
Geert Uytterhoeven902e7e62015-11-30 15:35:26 +010043 return spi_sync_transfer(to_spi_device(chip->gpio_chip.parent),
44 &xfer, 1);
Miguel Gaioead6db082010-10-27 15:33:18 -070045}
46
Miguel Gaioead6db082010-10-27 15:33:18 -070047static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
48{
Linus Walleijb2afc6f2015-12-03 18:20:29 +010049 struct gen_74x164_chip *chip = gpiochip_get_data(gc);
Geert Uytterhoeven902e7e62015-11-30 15:35:26 +010050 u8 bank = chip->registers - 1 - offset / 8;
Maxime Ripard20bc4d52012-09-10 22:35:39 +020051 u8 pin = offset % 8;
Miguel Gaioead6db082010-10-27 15:33:18 -070052 int ret;
53
54 mutex_lock(&chip->lock);
Maxime Ripard20bc4d52012-09-10 22:35:39 +020055 ret = (chip->buffer[bank] >> pin) & 0x1;
Miguel Gaioead6db082010-10-27 15:33:18 -070056 mutex_unlock(&chip->lock);
57
58 return ret;
59}
60
61static void gen_74x164_set_value(struct gpio_chip *gc,
62 unsigned offset, int val)
63{
Linus Walleijb2afc6f2015-12-03 18:20:29 +010064 struct gen_74x164_chip *chip = gpiochip_get_data(gc);
Geert Uytterhoeven902e7e62015-11-30 15:35:26 +010065 u8 bank = chip->registers - 1 - offset / 8;
Maxime Ripard20bc4d52012-09-10 22:35:39 +020066 u8 pin = offset % 8;
Miguel Gaioead6db082010-10-27 15:33:18 -070067
68 mutex_lock(&chip->lock);
69 if (val)
Maxime Ripard20bc4d52012-09-10 22:35:39 +020070 chip->buffer[bank] |= (1 << pin);
Miguel Gaioead6db082010-10-27 15:33:18 -070071 else
Maxime Ripard20bc4d52012-09-10 22:35:39 +020072 chip->buffer[bank] &= ~(1 << pin);
Miguel Gaioead6db082010-10-27 15:33:18 -070073
74 __gen_74x164_write_config(chip);
75 mutex_unlock(&chip->lock);
76}
77
Geert Uytterhoevend46ab682016-03-14 16:19:18 +010078static void gen_74x164_set_multiple(struct gpio_chip *gc, unsigned long *mask,
79 unsigned long *bits)
80{
81 struct gen_74x164_chip *chip = gpiochip_get_data(gc);
82 unsigned int i, idx, shift;
83 u8 bank, bankmask;
84
85 mutex_lock(&chip->lock);
86 for (i = 0, bank = chip->registers - 1; i < chip->registers;
87 i++, bank--) {
88 idx = i / sizeof(*mask);
89 shift = i % sizeof(*mask) * BITS_PER_BYTE;
90 bankmask = mask[idx] >> shift;
91 if (!bankmask)
92 continue;
93
94 chip->buffer[bank] &= ~bankmask;
95 chip->buffer[bank] |= bankmask & (bits[idx] >> shift);
96 }
97 __gen_74x164_write_config(chip);
98 mutex_unlock(&chip->lock);
99}
100
H Hartley Sweetena3cc68c2011-05-27 16:35:59 -0700101static int gen_74x164_direction_output(struct gpio_chip *gc,
102 unsigned offset, int val)
103{
104 gen_74x164_set_value(gc, offset, val);
105 return 0;
106}
107
Bill Pemberton38363092012-11-19 13:22:34 -0500108static int gen_74x164_probe(struct spi_device *spi)
Miguel Gaioead6db082010-10-27 15:33:18 -0700109{
110 struct gen_74x164_chip *chip;
Geert Uytterhoeven410f4572015-11-30 15:35:25 +0100111 u32 nregs;
Miguel Gaioead6db082010-10-27 15:33:18 -0700112 int ret;
113
Miguel Gaioead6db082010-10-27 15:33:18 -0700114 /*
115 * bits_per_word cannot be configured in platform data
116 */
117 spi->bits_per_word = 8;
118
119 ret = spi_setup(spi);
120 if (ret < 0)
121 return ret;
122
Geert Uytterhoeven410f4572015-11-30 15:35:25 +0100123 if (of_property_read_u32(spi->dev.of_node, "registers-number",
124 &nregs)) {
125 dev_err(&spi->dev,
126 "Missing registers-number property in the DT.\n");
127 return -EINVAL;
128 }
129
130 chip = devm_kzalloc(&spi->dev, sizeof(*chip) + nregs, GFP_KERNEL);
Miguel Gaioead6db082010-10-27 15:33:18 -0700131 if (!chip)
132 return -ENOMEM;
133
Jingoo Han6c0cf422013-03-15 18:17:18 +0900134 spi_set_drvdata(spi, chip);
Miguel Gaioead6db082010-10-27 15:33:18 -0700135
H Hartley Sweetena3cc68c2011-05-27 16:35:59 -0700136 chip->gpio_chip.label = spi->modalias;
137 chip->gpio_chip.direction_output = gen_74x164_direction_output;
Miguel Gaioead6db082010-10-27 15:33:18 -0700138 chip->gpio_chip.get = gen_74x164_get_value;
139 chip->gpio_chip.set = gen_74x164_set_value;
Geert Uytterhoevend46ab682016-03-14 16:19:18 +0100140 chip->gpio_chip.set_multiple = gen_74x164_set_multiple;
Alexander Shiyan61e73802013-12-07 14:08:22 +0400141 chip->gpio_chip.base = -1;
Maxime Ripard20bc4d52012-09-10 22:35:39 +0200142
Geert Uytterhoeven410f4572015-11-30 15:35:25 +0100143 chip->registers = nregs;
Maxime Ripard20bc4d52012-09-10 22:35:39 +0200144 chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers;
Maxime Ripard20bc4d52012-09-10 22:35:39 +0200145
Linus Walleij9fb1f392013-12-04 14:42:46 +0100146 chip->gpio_chip.can_sleep = true;
Linus Walleij58383c72015-11-04 09:56:26 +0100147 chip->gpio_chip.parent = &spi->dev;
Miguel Gaioead6db082010-10-27 15:33:18 -0700148 chip->gpio_chip.owner = THIS_MODULE;
149
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400150 mutex_init(&chip->lock);
151
Miguel Gaioead6db082010-10-27 15:33:18 -0700152 ret = __gen_74x164_write_config(chip);
153 if (ret) {
154 dev_err(&spi->dev, "Failed writing: %d\n", ret);
155 goto exit_destroy;
156 }
157
Linus Walleijb2afc6f2015-12-03 18:20:29 +0100158 ret = gpiochip_add_data(&chip->gpio_chip, chip);
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400159 if (!ret)
160 return 0;
Miguel Gaioead6db082010-10-27 15:33:18 -0700161
162exit_destroy:
Miguel Gaioead6db082010-10-27 15:33:18 -0700163 mutex_destroy(&chip->lock);
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400164
Miguel Gaioead6db082010-10-27 15:33:18 -0700165 return ret;
166}
167
Bill Pemberton206210c2012-11-19 13:25:50 -0500168static int gen_74x164_remove(struct spi_device *spi)
Miguel Gaioead6db082010-10-27 15:33:18 -0700169{
Alexander Shiyanbcc05622013-12-07 14:08:23 +0400170 struct gen_74x164_chip *chip = spi_get_drvdata(spi);
Miguel Gaioead6db082010-10-27 15:33:18 -0700171
abdoulaye berthe9f5132a2014-07-12 22:30:12 +0200172 gpiochip_remove(&chip->gpio_chip);
173 mutex_destroy(&chip->lock);
Miguel Gaioead6db082010-10-27 15:33:18 -0700174
abdoulaye berthe9f5132a2014-07-12 22:30:12 +0200175 return 0;
Miguel Gaioead6db082010-10-27 15:33:18 -0700176}
177
Maxime Ripard0a90a9f2012-09-07 14:18:13 +0200178static const struct of_device_id gen_74x164_dt_ids[] = {
179 { .compatible = "fairchild,74hc595" },
Nicolas Saenz Julienne80018bd2016-03-14 23:32:10 +0000180 { .compatible = "nxp,74lvc594" },
Maxime Ripard0a90a9f2012-09-07 14:18:13 +0200181 {},
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",
Sachin Kamat187a53a2013-09-19 17:28:08 +0530188 .of_match_table = gen_74x164_dt_ids,
Miguel Gaioead6db082010-10-27 15:33:18 -0700189 },
190 .probe = gen_74x164_probe,
Bill Pemberton8283c4f2012-11-19 13:20:08 -0500191 .remove = gen_74x164_remove,
Miguel Gaioead6db082010-10-27 15:33:18 -0700192};
Maxime Ripardab3b8782012-09-05 10:40:50 +0200193module_spi_driver(gen_74x164_driver);
Miguel Gaioead6db082010-10-27 15:33:18 -0700194
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");