mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-08-27 04:18:51 +09:00
![Simon Glass](/assets/img/avatar_default.png)
At present U-Boot sort-of supports the standard way of reading GPIOs from device tree nodes, but the support is incomplete, a bit clunky and only works for GPIO bindings where #gpio-cells is 2. Add new functions to request GPIOs, taking full account of the device tree binding. These permit requesting a GPIO with a simple call like: gpio_request_by_name(dev, "cd-gpios", 0, &desc, GPIOD_IS_IN); This will request the GPIO, looking at the device's node which might be this, for example: cd-gpios = <&gpio TEGRA_GPIO(B, 3) GPIO_ACTIVE_LOW>; The GPIO will be set to input mode in this case and polarity will be honoured by the GPIO calls. It is also possible to request and free a list of GPIOs. Signed-off-by: Simon Glass <sjg@chromium.org>
208 lines
5.0 KiB
C
208 lines
5.0 KiB
C
/*
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* Copyright (c) 2011 The Chromium OS Authors.
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.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 <dt-bindings/gpio/gpio.h>
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DECLARE_GLOBAL_DATA_PTR;
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/* Flags for each GPIO */
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#define GPIOF_OUTPUT (1 << 0) /* Currently set as an output */
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#define GPIOF_HIGH (1 << 1) /* Currently set high */
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struct gpio_state {
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const char *label; /* label given by requester */
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u8 flags; /* flags (GPIOF_...) */
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};
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/* Access routines for GPIO state */
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static u8 *get_gpio_flags(struct udevice *dev, unsigned offset)
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{
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struct gpio_dev_priv *uc_priv = dev->uclass_priv;
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struct gpio_state *state = dev_get_priv(dev);
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if (offset >= uc_priv->gpio_count) {
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static u8 invalid_flags;
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printf("sandbox_gpio: error: invalid gpio %u\n", offset);
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return &invalid_flags;
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}
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return &state[offset].flags;
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}
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static int get_gpio_flag(struct udevice *dev, unsigned offset, int flag)
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{
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return (*get_gpio_flags(dev, offset) & flag) != 0;
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}
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static int set_gpio_flag(struct udevice *dev, unsigned offset, int flag,
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int value)
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{
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u8 *gpio = get_gpio_flags(dev, offset);
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if (value)
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*gpio |= flag;
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else
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*gpio &= ~flag;
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return 0;
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}
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/*
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* Back-channel sandbox-internal-only access to GPIO state
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*/
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int sandbox_gpio_get_value(struct udevice *dev, unsigned offset)
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{
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if (get_gpio_flag(dev, offset, GPIOF_OUTPUT))
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debug("sandbox_gpio: get_value on output gpio %u\n", offset);
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return get_gpio_flag(dev, offset, GPIOF_HIGH);
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}
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int sandbox_gpio_set_value(struct udevice *dev, unsigned offset, int value)
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{
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return set_gpio_flag(dev, offset, GPIOF_HIGH, value);
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}
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int sandbox_gpio_get_direction(struct udevice *dev, unsigned offset)
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{
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return get_gpio_flag(dev, offset, GPIOF_OUTPUT);
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}
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int sandbox_gpio_set_direction(struct udevice *dev, unsigned offset, int output)
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{
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return set_gpio_flag(dev, offset, GPIOF_OUTPUT, output);
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}
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/*
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* These functions implement the public interface within U-Boot
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*/
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/* set GPIO port 'offset' as an input */
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static int sb_gpio_direction_input(struct udevice *dev, unsigned offset)
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{
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debug("%s: offset:%u\n", __func__, offset);
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return sandbox_gpio_set_direction(dev, offset, 0);
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}
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/* set GPIO port 'offset' as an output, with polarity 'value' */
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static int sb_gpio_direction_output(struct udevice *dev, unsigned offset,
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int value)
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{
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debug("%s: offset:%u, value = %d\n", __func__, offset, value);
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return sandbox_gpio_set_direction(dev, offset, 1) |
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sandbox_gpio_set_value(dev, offset, value);
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}
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/* read GPIO IN value of port 'offset' */
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static int sb_gpio_get_value(struct udevice *dev, unsigned offset)
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{
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debug("%s: offset:%u\n", __func__, offset);
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return sandbox_gpio_get_value(dev, offset);
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}
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/* write GPIO OUT value to port 'offset' */
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static int sb_gpio_set_value(struct udevice *dev, unsigned offset, int value)
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{
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debug("%s: offset:%u, value = %d\n", __func__, offset, value);
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if (!sandbox_gpio_get_direction(dev, offset)) {
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printf("sandbox_gpio: error: set_value on input gpio %u\n",
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offset);
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return -1;
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}
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return sandbox_gpio_set_value(dev, offset, value);
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}
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static int sb_gpio_get_function(struct udevice *dev, unsigned offset)
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{
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if (get_gpio_flag(dev, offset, GPIOF_OUTPUT))
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return GPIOF_OUTPUT;
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return GPIOF_INPUT;
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}
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static int sb_gpio_xlate(struct udevice *dev, struct gpio_desc *desc,
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struct fdtdec_phandle_args *args)
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{
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desc->offset = args->args[0];
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if (args->args_count < 2)
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return 0;
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if (args->args[1] & GPIO_ACTIVE_LOW)
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desc->flags |= GPIOD_ACTIVE_LOW;
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if (args->args[1] & 2)
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desc->flags |= GPIOD_IS_IN;
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if (args->args[1] & 4)
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desc->flags |= GPIOD_IS_OUT;
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if (args->args[1] & 8)
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desc->flags |= GPIOD_IS_OUT_ACTIVE;
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return 0;
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}
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static const struct dm_gpio_ops gpio_sandbox_ops = {
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.direction_input = sb_gpio_direction_input,
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.direction_output = sb_gpio_direction_output,
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.get_value = sb_gpio_get_value,
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.set_value = sb_gpio_set_value,
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.get_function = sb_gpio_get_function,
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.xlate = sb_gpio_xlate,
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};
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static int sandbox_gpio_ofdata_to_platdata(struct udevice *dev)
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{
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struct gpio_dev_priv *uc_priv = dev->uclass_priv;
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uc_priv->gpio_count = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
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"num-gpios", 0);
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uc_priv->bank_name = fdt_getprop(gd->fdt_blob, dev->of_offset,
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"gpio-bank-name", NULL);
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return 0;
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}
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static int gpio_sandbox_probe(struct udevice *dev)
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{
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struct gpio_dev_priv *uc_priv = dev->uclass_priv;
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if (dev->of_offset == -1) {
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/* Tell the uclass how many GPIOs we have */
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uc_priv->gpio_count = CONFIG_SANDBOX_GPIO_COUNT;
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}
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dev->priv = calloc(sizeof(struct gpio_state), uc_priv->gpio_count);
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return 0;
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}
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static int gpio_sandbox_remove(struct udevice *dev)
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{
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free(dev->priv);
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return 0;
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}
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static const struct udevice_id sandbox_gpio_ids[] = {
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{ .compatible = "sandbox,gpio" },
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{ }
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};
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U_BOOT_DRIVER(gpio_sandbox) = {
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.name = "gpio_sandbox",
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.id = UCLASS_GPIO,
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.of_match = sandbox_gpio_ids,
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.ofdata_to_platdata = sandbox_gpio_ofdata_to_platdata,
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.probe = gpio_sandbox_probe,
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.remove = gpio_sandbox_remove,
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.ops = &gpio_sandbox_ops,
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};
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