Re: [U-Boot] [PATCH v2] reset: Add generic GPIO reset driver

Hi,

On 27/04/2018 14:53, Mario Six wrote:

Some reset lines are implemented by toggling the line via a GPIO.

Add a driver to properly drive such reset lines.

You are defining a "gpio-reset" binding which has always been rejected under Linux, so I'm not sure it's a good idea to add it in U-Boot only...

Neil

Signed-off-by: Mario Six mario.six@gdsys.cc

v1 -> v2: No changes

---

drivers/reset/Kconfig | 7 ++++ drivers/reset/Makefile | 1 + drivers/reset/gpio-reset.c | 100 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 108 insertions(+) create mode 100644 drivers/reset/gpio-reset.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig index 33c39b7fb6..b6e1da009c 100644 --- a/drivers/reset/Kconfig +++ b/drivers/reset/Kconfig @@ -98,4 +98,11 @@ config RESET_SOCFPGA help Support for reset controller on SoCFPGA platform.

+config GPIO_RESET

• bool "Reset driver for GPIO-based reset lines"
• depends on DM_RESET
• help

•  Support a generic reset controller that encapsulates a number of
  

•  GPIOs of which each controls a single reset line.
  

endmenu diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile index ad08be4c8c..4a9d4006a3 100644 --- a/drivers/reset/Makefile +++ b/drivers/reset/Makefile @@ -15,3 +15,4 @@ obj-$(CONFIG_AST2500_RESET) += ast2500-reset.o obj-$(CONFIG_RESET_ROCKCHIP) += reset-rockchip.o obj-$(CONFIG_RESET_MESON) += reset-meson.o obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o +obj-$(CONFIG_GPIO_RESET) += gpio-reset.o diff --git a/drivers/reset/gpio-reset.c b/drivers/reset/gpio-reset.c new file mode 100644 index 0000000000..52dd47df60 --- /dev/null +++ b/drivers/reset/gpio-reset.c @@ -0,0 +1,100 @@ +/*

• • (C) Copyright 2017
• • Mario Six, Guntermann & Drunck GmbH, mario.six@gdsys.cc
• • SPDX-License-Identifier: GPL-2.0+
• */

+#include <common.h> +#include <dm.h> +#include <reset-uclass.h> +#include <asm/gpio.h>

+struct gpio_reset_priv {

• struct gpio_desc gpios[16];
• uint gpio_num;

+};

+static int gpio_reset_request(struct reset_ctl *reset_ctl) +{

• struct gpio_reset_priv *priv = dev_get_priv(reset_ctl->dev);
• debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,

•      reset_ctl->dev, reset_ctl->id);
  

• /* Reset ID = number of GPIO in list */
• if (reset_ctl->id >= priv->gpio_num)

• return -EINVAL;
  

• return 0;

+}

+static int gpio_reset_free(struct reset_ctl *reset_ctl) +{

• debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,

•      reset_ctl->dev, reset_ctl->id);
  

• return 0;

+}

+static int gpio_reset_assert(struct reset_ctl *reset_ctl) +{

• struct gpio_reset_priv *priv = dev_get_priv(reset_ctl->dev);
• debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,

•      reset_ctl->dev, reset_ctl->id);
  

• dm_gpio_set_value(&priv->gpios[reset_ctl->id], 1);
• return 0;

+}

+static int gpio_reset_deassert(struct reset_ctl *reset_ctl) +{

• struct gpio_reset_priv *priv = dev_get_priv(reset_ctl->dev);
• debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,

•      reset_ctl->dev, reset_ctl->id);
  

• dm_gpio_set_value(&priv->gpios[reset_ctl->id], 0);
• return 0;

+}

+struct reset_ops gpio_reset_ops = {

• .request = gpio_reset_request,
• .free = gpio_reset_free,
• .rst_assert = gpio_reset_assert,
• .rst_deassert = gpio_reset_deassert,

+};

+static int gpio_reset_probe(struct udevice *dev) +{

• struct gpio_reset_priv *priv = dev_get_priv(dev);
• int ret;
• debug("%s(dev=%p)\n", __func__, dev);
• ret = gpio_request_list_by_name(dev, "gpios", priv->gpios,

• 			ARRAY_SIZE(priv->gpios), GPIOD_IS_OUT);
  

• if (ret <= 0)

• return ret;
  

• priv->gpio_num = ret;
• return 0;

+}

+static const struct udevice_id gpio_reset[] = {

• { .compatible = "gpio-reset", },
• { /* sentinel */ }

+};

+U_BOOT_DRIVER(gpio_reset) = {

• .name = "gpio_reset",
• .id = UCLASS_RESET,
• .of_match = gpio_reset,
• .probe = gpio_reset_probe,
• .ops = &gpio_reset_ops,
• .priv_auto_alloc_size = sizeof(struct gpio_reset_priv),

+};

2.16.1