--- /dev/null
+/*
+ * 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,
+};
projects / oweals / u-boot.git / commitdiff