diff options
Diffstat (limited to 'drivers/gpio')
-rw-r--r-- | drivers/gpio/gpio-74x164.c | 68 |
1 files changed, 61 insertions, 7 deletions
diff --git a/drivers/gpio/gpio-74x164.c b/drivers/gpio/gpio-74x164.c index 2e31bd35769a..ed3e55161bdc 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); @@ -75,6 +111,11 @@ static int __devinit gen_74x164_probe(struct spi_device *spi) struct gen_74x164_chip_platform_data *pdata; int ret; + if (!spi->dev.of_node) { + dev_err(&spi->dev, "No device tree data available.\n"); + return -EINVAL; + } + /* * bits_per_word cannot be configured in platform data */ @@ -104,7 +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.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; |