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![Simon Glass](/assets/img/avatar_default.png)
This construct is quite long-winded. In earlier days it made some sense since auto-allocation was a strange concept. But with driver model now used pretty universally, we can shorten this to 'auto'. This reduces verbosity and makes it easier to read. Coincidentally it also ensures that every declaration is on one line, thus making dtoc's job easier. Signed-off-by: Simon Glass <sjg@chromium.org>
193 lines
4.2 KiB
C
193 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Take drivers/gpio/gpio-74x164.c as reference.
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*
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* 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
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*
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* Copyright (C) 2016 Peng Fan <van.freenix@gmail.com>
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*
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*/
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#include <common.h>
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#include <errno.h>
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#include <dm.h>
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#include <fdtdec.h>
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#include <malloc.h>
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#include <asm/gpio.h>
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#include <asm/io.h>
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#include <dm/device_compat.h>
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#include <dt-bindings/gpio/gpio.h>
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#include <spi.h>
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DECLARE_GLOBAL_DATA_PTR;
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/*
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* struct gen_74x164_chip - Data for 74Hx164
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*
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* @oe: OE pin
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* @nregs: number of registers
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* @buffer: buffer for chained chips
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*/
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#define GEN_74X164_NUMBER_GPIOS 8
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struct gen_74x164_priv {
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struct gpio_desc oe;
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u32 nregs;
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/*
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* Since the nregs are chained, every byte sent will make
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* the previous byte shift to the next register in the
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* chain. Thus, the first byte sent will end up in the last
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* register at the end of the transfer. So, to have a logical
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* numbering, store the bytes in reverse order.
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*/
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u8 *buffer;
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};
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static int gen_74x164_write_conf(struct udevice *dev)
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{
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struct gen_74x164_priv *priv = dev_get_priv(dev);
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int ret;
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ret = dm_spi_claim_bus(dev);
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if (ret)
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return ret;
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ret = dm_spi_xfer(dev, priv->nregs * 8, priv->buffer, NULL,
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SPI_XFER_BEGIN | SPI_XFER_END);
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dm_spi_release_bus(dev);
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return ret;
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}
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static int gen_74x164_get_value(struct udevice *dev, unsigned offset)
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{
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struct gen_74x164_priv *priv = dev_get_priv(dev);
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uint bank = priv->nregs - 1 - offset / 8;
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uint pin = offset % 8;
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return (priv->buffer[bank] >> pin) & 0x1;
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}
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static int gen_74x164_set_value(struct udevice *dev, unsigned offset,
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int value)
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{
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struct gen_74x164_priv *priv = dev_get_priv(dev);
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uint bank = priv->nregs - 1 - offset / 8;
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uint pin = offset % 8;
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int ret;
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if (value)
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priv->buffer[bank] |= 1 << pin;
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else
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priv->buffer[bank] &= ~(1 << pin);
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ret = gen_74x164_write_conf(dev);
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if (ret)
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return ret;
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return 0;
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}
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static int gen_74x164_direction_input(struct udevice *dev, unsigned offset)
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{
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return -ENOSYS;
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}
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static int gen_74x164_direction_output(struct udevice *dev, unsigned offset,
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int value)
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{
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return gen_74x164_set_value(dev, offset, value);
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}
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static int gen_74x164_get_function(struct udevice *dev, unsigned offset)
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{
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return GPIOF_OUTPUT;
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}
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static int gen_74x164_xlate(struct udevice *dev, struct gpio_desc *desc,
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struct ofnode_phandle_args *args)
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{
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desc->offset = args->args[0];
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desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0;
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return 0;
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}
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static const struct dm_gpio_ops gen_74x164_ops = {
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.direction_input = gen_74x164_direction_input,
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.direction_output = gen_74x164_direction_output,
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.get_value = gen_74x164_get_value,
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.set_value = gen_74x164_set_value,
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.get_function = gen_74x164_get_function,
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.xlate = gen_74x164_xlate,
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};
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static int gen_74x164_probe(struct udevice *dev)
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{
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struct gen_74x164_priv *priv = dev_get_priv(dev);
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struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
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char *str, name[32];
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int ret;
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const void *fdt = gd->fdt_blob;
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int node = dev_of_offset(dev);
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snprintf(name, sizeof(name), "%s_", dev->name);
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str = strdup(name);
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if (!str)
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return -ENOMEM;
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/*
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* See Linux kernel:
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* Documentation/devicetree/bindings/gpio/gpio-74x164.txt
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*/
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priv->nregs = fdtdec_get_int(fdt, node, "registers-number", 1);
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priv->buffer = calloc(priv->nregs, sizeof(u8));
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if (!priv->buffer) {
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ret = -ENOMEM;
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goto free_str;
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}
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ret = fdtdec_get_byte_array(fdt, node, "registers-default",
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priv->buffer, priv->nregs);
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if (ret)
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dev_dbg(dev, "No registers-default property\n");
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ret = gpio_request_by_name(dev, "oe-gpios", 0, &priv->oe,
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GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
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if (ret) {
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dev_dbg(dev, "No oe-pins property\n");
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}
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uc_priv->bank_name = str;
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uc_priv->gpio_count = priv->nregs * 8;
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ret = gen_74x164_write_conf(dev);
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if (ret)
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goto free_buf;
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dev_dbg(dev, "%s is ready\n", dev->name);
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return 0;
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free_buf:
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free(priv->buffer);
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free_str:
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free(str);
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return ret;
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}
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static const struct udevice_id gen_74x164_ids[] = {
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{ .compatible = "fairchild,74hc595" },
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{ }
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};
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U_BOOT_DRIVER(74x164) = {
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.name = "74x164",
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.id = UCLASS_GPIO,
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.ops = &gen_74x164_ops,
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.probe = gen_74x164_probe,
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.priv_auto = sizeof(struct gen_74x164_priv),
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.of_match = gen_74x164_ids,
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};
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