Some reset lines are implemented by toggling the line via a GPIO.
Add a driver to properly drive such reset lines.
Signed-off-by: Mario Six mario.six@gdsys.cc --- 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 71a786bab5..b8416fa85a 100644 --- a/drivers/reset/Kconfig +++ b/drivers/reset/Kconfig @@ -83,4 +83,11 @@ config RESET_ROCKCHIP though is that some reset signals, like I2C or MISC reset multiple devices.
+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 7d7e080c78..a5d766b183 100644 --- a/drivers/reset/Makefile +++ b/drivers/reset/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o obj-$(CONFIG_AST2500_RESET) += ast2500-reset.o obj-$(CONFIG_RESET_ROCKCHIP) += reset-rockchip.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), +};