#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)
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;
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);
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;
}
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);
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;
exit_destroy:
dev_set_drvdata(&spi->dev, NULL);
mutex_destroy(&chip->lock);
- kfree(chip);
return ret;
}
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>");
projects / ~andy / linux / blobdiff