diff options
Diffstat (limited to 'drivers/gpio/gpio-74x164.c')
| -rw-r--r-- | drivers/gpio/gpio-74x164.c | 103 |
1 files changed, 75 insertions, 28 deletions
diff --git a/drivers/gpio/gpio-74x164.c b/drivers/gpio/gpio-74x164.c index a31ad6f5d91..ed3e55161bd 100644 --- a/drivers/gpio/gpio-74x164.c +++ b/drivers/gpio/gpio-74x164.c @@ -14,14 +14,18 @@ #include <linux/spi/spi.h> #include <linux/spi/74x164.h> #include <linux/gpio.h> +#include <linux/of_gpio.h> #include <linux/slab.h> #include <linux/module.h> +#define GEN_74X164_NUMBER_GPIOS 8 + struct gen_74x164_chip { struct spi_device *spi; + u8 *buffer; struct gpio_chip gpio_chip; struct mutex lock; - u8 port_config; + u32 registers; }; static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc) @@ -31,17 +35,47 @@ static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc) static int __gen_74x164_write_config(struct gen_74x164_chip *chip) { - return spi_write(chip->spi, - &chip->port_config, sizeof(chip->port_config)); + struct spi_message message; + struct spi_transfer *msg_buf; + int i, ret = 0; + + msg_buf = kzalloc(chip->registers * sizeof(struct spi_transfer), + GFP_KERNEL); + if (!msg_buf) + return -ENOMEM; + + spi_message_init(&message); + + /* + * Since the registers are chained, every byte sent will make + * the previous byte shift to the next register in the + * chain. Thus, the first byte send will end up in the last + * register at the end of the transfer. So, to have a logical + * numbering, send the bytes in reverse order so that the last + * byte of the buffer will end up in the last register. + */ + for (i = chip->registers - 1; i >= 0; i--) { + msg_buf[i].tx_buf = chip->buffer +i; + msg_buf[i].len = sizeof(u8); + spi_message_add_tail(msg_buf + i, &message); + } + + ret = spi_sync(chip->spi, &message); + + kfree(msg_buf); + + return ret; } static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset) { struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc); + u8 bank = offset / 8; + u8 pin = offset % 8; int ret; mutex_lock(&chip->lock); - ret = (chip->port_config >> offset) & 0x1; + ret = (chip->buffer[bank] >> pin) & 0x1; mutex_unlock(&chip->lock); return ret; @@ -51,12 +85,14 @@ static void gen_74x164_set_value(struct gpio_chip *gc, unsigned offset, int val) { struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc); + u8 bank = offset / 8; + u8 pin = offset % 8; mutex_lock(&chip->lock); if (val) - chip->port_config |= (1 << offset); + chip->buffer[bank] |= (1 << pin); else - chip->port_config &= ~(1 << offset); + chip->buffer[bank] &= ~(1 << pin); __gen_74x164_write_config(chip); mutex_unlock(&chip->lock); @@ -75,9 +111,8 @@ static int __devinit gen_74x164_probe(struct spi_device *spi) struct gen_74x164_chip_platform_data *pdata; int ret; - pdata = spi->dev.platform_data; - if (!pdata || !pdata->base) { - dev_dbg(&spi->dev, "incorrect or missing platform data\n"); + if (!spi->dev.of_node) { + dev_err(&spi->dev, "No device tree data available.\n"); return -EINVAL; } @@ -90,10 +125,16 @@ static int __devinit gen_74x164_probe(struct spi_device *spi) if (ret < 0) return ret; - chip = kzalloc(sizeof(*chip), GFP_KERNEL); + chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL); if (!chip) return -ENOMEM; + pdata = spi->dev.platform_data; + if (pdata && pdata->base) + chip->gpio_chip.base = pdata->base; + else + chip->gpio_chip.base = -1; + mutex_init(&chip->lock); dev_set_drvdata(&spi->dev, chip); @@ -104,8 +145,20 @@ static int __devinit gen_74x164_probe(struct spi_device *spi) chip->gpio_chip.direction_output = gen_74x164_direction_output; chip->gpio_chip.get = gen_74x164_get_value; chip->gpio_chip.set = gen_74x164_set_value; - chip->gpio_chip.base = pdata->base; - chip->gpio_chip.ngpio = 8; + + if (of_property_read_u32(spi->dev.of_node, "registers-number", &chip->registers)) { + dev_err(&spi->dev, "Missing registers-number property in the DT.\n"); + ret = -EINVAL; + goto exit_destroy; + } + + chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers; + chip->buffer = devm_kzalloc(&spi->dev, chip->gpio_chip.ngpio, GFP_KERNEL); + if (!chip->buffer) { + ret = -ENOMEM; + goto exit_destroy; + } + chip->gpio_chip.can_sleep = 1; chip->gpio_chip.dev = &spi->dev; chip->gpio_chip.owner = THIS_MODULE; @@ -125,7 +178,6 @@ static int __devinit gen_74x164_probe(struct spi_device *spi) exit_destroy: dev_set_drvdata(&spi->dev, NULL); mutex_destroy(&chip->lock); - kfree(chip); return ret; } @@ -141,36 +193,31 @@ static int __devexit gen_74x164_remove(struct spi_device *spi) dev_set_drvdata(&spi->dev, NULL); ret = gpiochip_remove(&chip->gpio_chip); - if (!ret) { + if (!ret) mutex_destroy(&chip->lock); - kfree(chip); - } else + else dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n", ret); return ret; } +static const struct of_device_id gen_74x164_dt_ids[] = { + { .compatible = "fairchild,74hc595" }, + {}, +}; +MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids); + static struct spi_driver gen_74x164_driver = { .driver = { .name = "74x164", .owner = THIS_MODULE, + .of_match_table = of_match_ptr(gen_74x164_dt_ids), }, .probe = gen_74x164_probe, .remove = __devexit_p(gen_74x164_remove), }; - -static int __init gen_74x164_init(void) -{ - return spi_register_driver(&gen_74x164_driver); -} -subsys_initcall(gen_74x164_init); - -static void __exit gen_74x164_exit(void) -{ - spi_unregister_driver(&gen_74x164_driver); -} -module_exit(gen_74x164_exit); +module_spi_driver(gen_74x164_driver); MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>"); MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>"); |