Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 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> |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 15 | #include <linux/gpio.h> |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 16 | #include <linux/of_gpio.h> |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 17 | #include <linux/slab.h> |
Paul Gortmaker | bb207ef | 2011-07-03 13:38:09 -0400 | [diff] [blame] | 18 | #include <linux/module.h> |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 19 | |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 20 | #define GEN_74X164_NUMBER_GPIOS 8 |
| 21 | |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 22 | struct gen_74x164_chip { |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 23 | u8 *buffer; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 24 | struct gpio_chip gpio_chip; |
| 25 | struct mutex lock; |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 26 | u32 registers; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 27 | }; |
| 28 | |
Linus Walleij | 12610be | 2011-06-13 10:47:15 +0200 | [diff] [blame] | 29 | static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc) |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 30 | { |
| 31 | return container_of(gc, struct gen_74x164_chip, gpio_chip); |
| 32 | } |
| 33 | |
| 34 | static int __gen_74x164_write_config(struct gen_74x164_chip *chip) |
| 35 | { |
Alexander Shiyan | bcc0562 | 2013-12-07 14:08:23 +0400 | [diff] [blame] | 36 | struct spi_device *spi = to_spi_device(chip->gpio_chip.dev); |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 37 | 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 Shiyan | bcc0562 | 2013-12-07 14:08:23 +0400 | [diff] [blame] | 57 | msg_buf[i].tx_buf = chip->buffer + i; |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 58 | msg_buf[i].len = sizeof(u8); |
| 59 | spi_message_add_tail(msg_buf + i, &message); |
| 60 | } |
| 61 | |
Alexander Shiyan | bcc0562 | 2013-12-07 14:08:23 +0400 | [diff] [blame] | 62 | ret = spi_sync(spi, &message); |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 63 | |
| 64 | kfree(msg_buf); |
| 65 | |
| 66 | return ret; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 67 | } |
| 68 | |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 69 | static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset) |
| 70 | { |
Linus Walleij | 12610be | 2011-06-13 10:47:15 +0200 | [diff] [blame] | 71 | struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc); |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 72 | u8 bank = offset / 8; |
| 73 | u8 pin = offset % 8; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 74 | int ret; |
| 75 | |
| 76 | mutex_lock(&chip->lock); |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 77 | ret = (chip->buffer[bank] >> pin) & 0x1; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 78 | mutex_unlock(&chip->lock); |
| 79 | |
| 80 | return ret; |
| 81 | } |
| 82 | |
| 83 | static void gen_74x164_set_value(struct gpio_chip *gc, |
| 84 | unsigned offset, int val) |
| 85 | { |
Linus Walleij | 12610be | 2011-06-13 10:47:15 +0200 | [diff] [blame] | 86 | struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc); |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 87 | u8 bank = offset / 8; |
| 88 | u8 pin = offset % 8; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 89 | |
| 90 | mutex_lock(&chip->lock); |
| 91 | if (val) |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 92 | chip->buffer[bank] |= (1 << pin); |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 93 | else |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 94 | chip->buffer[bank] &= ~(1 << pin); |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 95 | |
| 96 | __gen_74x164_write_config(chip); |
| 97 | mutex_unlock(&chip->lock); |
| 98 | } |
| 99 | |
H Hartley Sweeten | a3cc68c | 2011-05-27 16:35:59 -0700 | [diff] [blame] | 100 | static 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 Pemberton | 3836309 | 2012-11-19 13:22:34 -0500 | [diff] [blame] | 107 | static int gen_74x164_probe(struct spi_device *spi) |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 108 | { |
| 109 | struct gen_74x164_chip *chip; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 110 | int ret; |
| 111 | |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 112 | /* |
| 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 Ripard | 72eac30 | 2012-09-05 10:40:51 +0200 | [diff] [blame] | 121 | chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL); |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 122 | if (!chip) |
| 123 | return -ENOMEM; |
| 124 | |
Jingoo Han | 6c0cf42 | 2013-03-15 18:17:18 +0900 | [diff] [blame] | 125 | spi_set_drvdata(spi, chip); |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 126 | |
H Hartley Sweeten | a3cc68c | 2011-05-27 16:35:59 -0700 | [diff] [blame] | 127 | chip->gpio_chip.label = spi->modalias; |
| 128 | chip->gpio_chip.direction_output = gen_74x164_direction_output; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 129 | chip->gpio_chip.get = gen_74x164_get_value; |
| 130 | chip->gpio_chip.set = gen_74x164_set_value; |
Alexander Shiyan | 61e7380 | 2013-12-07 14:08:22 +0400 | [diff] [blame] | 131 | chip->gpio_chip.base = -1; |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 132 | |
Alexander Shiyan | bcc0562 | 2013-12-07 14:08:23 +0400 | [diff] [blame] | 133 | 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 Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 138 | } |
| 139 | |
| 140 | chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers; |
Roland Stigge | a48221a | 2012-10-16 15:24:01 +0200 | [diff] [blame] | 141 | chip->buffer = devm_kzalloc(&spi->dev, chip->registers, GFP_KERNEL); |
Alexander Shiyan | bcc0562 | 2013-12-07 14:08:23 +0400 | [diff] [blame] | 142 | if (!chip->buffer) |
| 143 | return -ENOMEM; |
Maxime Ripard | 20bc4d5 | 2012-09-10 22:35:39 +0200 | [diff] [blame] | 144 | |
Linus Walleij | 9fb1f39 | 2013-12-04 14:42:46 +0100 | [diff] [blame] | 145 | chip->gpio_chip.can_sleep = true; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 146 | chip->gpio_chip.dev = &spi->dev; |
| 147 | chip->gpio_chip.owner = THIS_MODULE; |
| 148 | |
Alexander Shiyan | bcc0562 | 2013-12-07 14:08:23 +0400 | [diff] [blame] | 149 | mutex_init(&chip->lock); |
| 150 | |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 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(&chip->gpio_chip); |
Alexander Shiyan | bcc0562 | 2013-12-07 14:08:23 +0400 | [diff] [blame] | 158 | if (!ret) |
| 159 | return 0; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 160 | |
| 161 | exit_destroy: |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 162 | mutex_destroy(&chip->lock); |
Alexander Shiyan | bcc0562 | 2013-12-07 14:08:23 +0400 | [diff] [blame] | 163 | |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 164 | return ret; |
| 165 | } |
| 166 | |
Bill Pemberton | 206210c | 2012-11-19 13:25:50 -0500 | [diff] [blame] | 167 | static int gen_74x164_remove(struct spi_device *spi) |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 168 | { |
Alexander Shiyan | bcc0562 | 2013-12-07 14:08:23 +0400 | [diff] [blame] | 169 | struct gen_74x164_chip *chip = spi_get_drvdata(spi); |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 170 | |
abdoulaye berthe | 9f5132a | 2014-07-12 22:30:12 +0200 | [diff] [blame] | 171 | gpiochip_remove(&chip->gpio_chip); |
| 172 | mutex_destroy(&chip->lock); |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 173 | |
abdoulaye berthe | 9f5132a | 2014-07-12 22:30:12 +0200 | [diff] [blame] | 174 | return 0; |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 175 | } |
| 176 | |
Maxime Ripard | 0a90a9f | 2012-09-07 14:18:13 +0200 | [diff] [blame] | 177 | static const struct of_device_id gen_74x164_dt_ids[] = { |
| 178 | { .compatible = "fairchild,74hc595" }, |
| 179 | {}, |
| 180 | }; |
| 181 | MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids); |
| 182 | |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 183 | static struct spi_driver gen_74x164_driver = { |
| 184 | .driver = { |
H Hartley Sweeten | a3cc68c | 2011-05-27 16:35:59 -0700 | [diff] [blame] | 185 | .name = "74x164", |
Sachin Kamat | 187a53a | 2013-09-19 17:28:08 +0530 | [diff] [blame] | 186 | .of_match_table = gen_74x164_dt_ids, |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 187 | }, |
| 188 | .probe = gen_74x164_probe, |
Bill Pemberton | 8283c4f | 2012-11-19 13:20:08 -0500 | [diff] [blame] | 189 | .remove = gen_74x164_remove, |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 190 | }; |
Maxime Ripard | ab3b878 | 2012-09-05 10:40:50 +0200 | [diff] [blame] | 191 | module_spi_driver(gen_74x164_driver); |
Miguel Gaio | ead6db08 | 2010-10-27 15:33:18 -0700 | [diff] [blame] | 192 | |
| 193 | MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>"); |
| 194 | MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>"); |
| 195 | MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register"); |
| 196 | MODULE_LICENSE("GPL v2"); |