summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpio-74x164.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/gpio/gpio-74x164.c')
-rw-r--r--drivers/gpio/gpio-74x164.c203
1 files changed, 203 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-74x164.c b/drivers/gpio/gpio-74x164.c
new file mode 100644
index 0000000000..e00c333105
--- /dev/null
+++ b/drivers/gpio/gpio-74x164.c
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
+ *
+ * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+#define GEN_74X164_NUMBER_GPIOS 8
+
+struct gen_74x164_chip {
+ struct gpio_chip gpio_chip;
+ struct mutex lock;
+ struct gpio_desc *gpiod_oe;
+ u32 registers;
+ /*
+ * 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 sent will end up in the last
+ * register at the end of the transfer. So, to have a logical
+ * numbering, store the bytes in reverse order.
+ */
+ u8 buffer[];
+};
+
+static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
+{
+ return spi_write(to_spi_device(chip->gpio_chip.parent), chip->buffer,
+ chip->registers);
+}
+
+static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
+{
+ struct gen_74x164_chip *chip = gpiochip_get_data(gc);
+ u8 bank = chip->registers - 1 - offset / 8;
+ u8 pin = offset % 8;
+ int ret;
+
+ mutex_lock(&chip->lock);
+ ret = (chip->buffer[bank] >> pin) & 0x1;
+ mutex_unlock(&chip->lock);
+
+ return ret;
+}
+
+static void gen_74x164_set_value(struct gpio_chip *gc,
+ unsigned offset, int val)
+{
+ struct gen_74x164_chip *chip = gpiochip_get_data(gc);
+ u8 bank = chip->registers - 1 - offset / 8;
+ u8 pin = offset % 8;
+
+ mutex_lock(&chip->lock);
+ if (val)
+ chip->buffer[bank] |= (1 << pin);
+ else
+ chip->buffer[bank] &= ~(1 << pin);
+
+ __gen_74x164_write_config(chip);
+ mutex_unlock(&chip->lock);
+}
+
+static void gen_74x164_set_multiple(struct gpio_chip *gc, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct gen_74x164_chip *chip = gpiochip_get_data(gc);
+ unsigned long offset;
+ unsigned long bankmask;
+ size_t bank;
+ unsigned long bitmask;
+
+ mutex_lock(&chip->lock);
+ for_each_set_clump8(offset, bankmask, mask, chip->registers * 8) {
+ bank = chip->registers - 1 - offset / 8;
+ bitmask = bitmap_get_value8(bits, offset) & bankmask;
+
+ chip->buffer[bank] &= ~bankmask;
+ chip->buffer[bank] |= bitmask;
+ }
+ __gen_74x164_write_config(chip);
+ mutex_unlock(&chip->lock);
+}
+
+static int gen_74x164_direction_output(struct gpio_chip *gc,
+ unsigned offset, int val)
+{
+ gen_74x164_set_value(gc, offset, val);
+ return 0;
+}
+
+static int gen_74x164_probe(struct spi_device *spi)
+{
+ struct gen_74x164_chip *chip;
+ u32 nregs;
+ int ret;
+
+ /*
+ * bits_per_word cannot be configured in platform data
+ */
+ spi->bits_per_word = 8;
+
+ ret = spi_setup(spi);
+ if (ret < 0)
+ return ret;
+
+ ret = device_property_read_u32(&spi->dev, "registers-number", &nregs);
+ if (ret) {
+ dev_err(&spi->dev, "Missing 'registers-number' property.\n");
+ return -EINVAL;
+ }
+
+ chip = devm_kzalloc(&spi->dev, sizeof(*chip) + nregs, GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->gpiod_oe = devm_gpiod_get_optional(&spi->dev, "enable",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(chip->gpiod_oe))
+ return PTR_ERR(chip->gpiod_oe);
+
+ gpiod_set_value_cansleep(chip->gpiod_oe, 1);
+
+ spi_set_drvdata(spi, chip);
+
+ chip->gpio_chip.label = spi->modalias;
+ 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.set_multiple = gen_74x164_set_multiple;
+ chip->gpio_chip.base = -1;
+
+ chip->registers = nregs;
+ chip->gpio_chip.ngpio = GEN_74X164_NUMBER_GPIOS * chip->registers;
+
+ chip->gpio_chip.can_sleep = true;
+ chip->gpio_chip.parent = &spi->dev;
+ chip->gpio_chip.owner = THIS_MODULE;
+
+ mutex_init(&chip->lock);
+
+ ret = __gen_74x164_write_config(chip);
+ if (ret) {
+ dev_err(&spi->dev, "Failed writing: %d\n", ret);
+ goto exit_destroy;
+ }
+
+ ret = gpiochip_add_data(&chip->gpio_chip, chip);
+ if (!ret)
+ return 0;
+
+exit_destroy:
+ mutex_destroy(&chip->lock);
+
+ return ret;
+}
+
+static void gen_74x164_remove(struct spi_device *spi)
+{
+ struct gen_74x164_chip *chip = spi_get_drvdata(spi);
+
+ gpiod_set_value_cansleep(chip->gpiod_oe, 0);
+ gpiochip_remove(&chip->gpio_chip);
+ mutex_destroy(&chip->lock);
+}
+
+static const struct spi_device_id gen_74x164_spi_ids[] = {
+ { .name = "74hc595" },
+ { .name = "74lvc594" },
+ {},
+};
+MODULE_DEVICE_TABLE(spi, gen_74x164_spi_ids);
+
+static const struct of_device_id gen_74x164_dt_ids[] = {
+ { .compatible = "fairchild,74hc595" },
+ { .compatible = "nxp,74lvc594" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids);
+
+static struct spi_driver gen_74x164_driver = {
+ .driver = {
+ .name = "74x164",
+ .of_match_table = gen_74x164_dt_ids,
+ },
+ .probe = gen_74x164_probe,
+ .remove = gen_74x164_remove,
+ .id_table = gen_74x164_spi_ids,
+};
+module_spi_driver(gen_74x164_driver);
+
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
+MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
+MODULE_LICENSE("GPL v2");