diff options
Diffstat (limited to 'drivers/gpio/74x164_gpio.c')
| -rw-r--r-- | drivers/gpio/74x164_gpio.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/drivers/gpio/74x164_gpio.c b/drivers/gpio/74x164_gpio.c new file mode 100644 index 0000000000..9ac10a745d --- /dev/null +++ b/drivers/gpio/74x164_gpio.c @@ -0,0 +1,193 @@ +/* + * Take drivers/gpio/gpio-74x164.c as reference. + * + * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver + * + * Copyright (C) 2016 Peng Fan <van.freenix@gmail.com> + * + * SPDX-License-Identifier: GPL-2.0+ + * + */ + +#include <common.h> +#include <errno.h> +#include <dm.h> +#include <fdtdec.h> +#include <malloc.h> +#include <asm/gpio.h> +#include <asm/io.h> +#include <dt-bindings/gpio/gpio.h> +#include <spi.h> + +DECLARE_GLOBAL_DATA_PTR; + +/* + * struct gen_74x164_chip - Data for 74Hx164 + * + * @oe: OE pin + * @nregs: number of registers + * @buffer: buffer for chained chips + */ +#define GEN_74X164_NUMBER_GPIOS 8 + +struct gen_74x164_priv { + struct gpio_desc oe; + u32 nregs; + /* + * Since the nregs 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_conf(struct udevice *dev) +{ + struct gen_74x164_priv *priv = dev_get_priv(dev); + int ret; + + ret = dm_spi_claim_bus(dev); + if (ret) + return ret; + + ret = dm_spi_xfer(dev, priv->nregs * 8, priv->buffer, NULL, + SPI_XFER_BEGIN | SPI_XFER_END); + + dm_spi_release_bus(dev); + + return ret; +} + +static int gen_74x164_get_value(struct udevice *dev, unsigned offset) +{ + struct gen_74x164_priv *priv = dev_get_priv(dev); + uint bank = priv->nregs - 1 - offset / 8; + uint pin = offset % 8; + + return (priv->buffer[bank] >> pin) & 0x1; +} + +static int gen_74x164_set_value(struct udevice *dev, unsigned offset, + int value) +{ + struct gen_74x164_priv *priv = dev_get_priv(dev); + uint bank = priv->nregs - 1 - offset / 8; + uint pin = offset % 8; + int ret; + + if (value) + priv->buffer[bank] |= 1 << pin; + else + priv->buffer[bank] &= ~(1 << pin); + + ret = gen_74x164_write_conf(dev); + if (ret) + return ret; + + return 0; +} + +static int gen_74x164_direction_input(struct udevice *dev, unsigned offset) +{ + return -ENOSYS; +} + +static int gen_74x164_direction_output(struct udevice *dev, unsigned offset, + int value) +{ + return gen_74x164_set_value(dev, offset, value); +} + +static int gen_74x164_get_function(struct udevice *dev, unsigned offset) +{ + return GPIOF_OUTPUT; +} + +static int gen_74x164_xlate(struct udevice *dev, struct gpio_desc *desc, + struct fdtdec_phandle_args *args) +{ + desc->offset = args->args[0]; + desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0; + + return 0; +} + +static const struct dm_gpio_ops gen_74x164_ops = { + .direction_input = gen_74x164_direction_input, + .direction_output = gen_74x164_direction_output, + .get_value = gen_74x164_get_value, + .set_value = gen_74x164_set_value, + .get_function = gen_74x164_get_function, + .xlate = gen_74x164_xlate, +}; + +static int gen_74x164_probe(struct udevice *dev) +{ + struct gen_74x164_priv *priv = dev_get_priv(dev); + struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev); + char *str, name[32]; + int ret; + const void *fdt = gd->fdt_blob; + int node = dev->of_offset; + + snprintf(name, sizeof(name), "%s_", dev->name); + str = strdup(name); + if (!str) + return -ENOMEM; + + /* + * See Linux kernel: + * Documentation/devicetree/bindings/gpio/gpio-74x164.txt + */ + priv->nregs = fdtdec_get_int(fdt, node, "registers-number", 1); + priv->buffer = calloc(priv->nregs, sizeof(u8)); + if (!priv->buffer) { + ret = -ENOMEM; + goto free_str; + } + + ret = fdtdec_get_byte_array(fdt, node, "registers-default", + priv->buffer, priv->nregs); + if (ret) + dev_dbg(dev, "No registers-default property\n"); + + ret = gpio_request_by_name(dev, "oe-gpios", 0, &priv->oe, + GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE); + if (ret) { + dev_err(dev, "No oe-pins property\n"); + goto free_buf; + } + + uc_priv->bank_name = str; + uc_priv->gpio_count = priv->nregs * 8; + + ret = gen_74x164_write_conf(dev); + if (ret) + goto free_buf; + + dev_dbg(dev, "%s is ready\n", dev->name); + + return 0; + +free_buf: + free(priv->buffer); +free_str: + free(str); + return ret; +} + +static const struct udevice_id gen_74x164_ids[] = { + { .compatible = "fairchild,74hc595" }, + { } +}; + +U_BOOT_DRIVER(74x164) = { + .name = "74x164", + .id = UCLASS_GPIO, + .ops = &gen_74x164_ops, + .probe = gen_74x164_probe, + .priv_auto_alloc_size = sizeof(struct gen_74x164_priv), + .of_match = gen_74x164_ids, +}; |
