[PATCH 2/5 v3] reset: Add a Gemini reset controller

[Philipp Zabel]

On Mon, 2017-05-15 at 19:19 +0200, Linus Walleij wrote:
> The Cortina Systems Gemini reset controller is a simple
> 32bit register with self-deasserting reset lines. It is
> accessed using regmap over syscon.
> 
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>

Patches 1 and 2
Acked-by: Philipp Zabel <p.zabel at pengutronix.de>
to be merged through arm-soc.

regards
Philipp

> ---
> ChangeLog v2->v3:
> - Use the syscon node to probe the driver.
> - Sebastian: when you're happy with this please ACK it so I
>   can merge it through ARM SoC. This is needed because of
>   the mess of #include <dt-bindings/*> from the DT bindings
>   that is then used all over the DTS files.
> ChangeLog v1->v2:
> - Add an explicit GPL license statement.
> - Move the reset controller to be identical to the sycon
>   node, no need to a separate child node for this.
> - Drop unneeded struct device *dev pointer from state
>   container.
> - Print error code on missing regmap.
> - Use #define from the <dt-bindings/*> to indicate that we
>   always set the CPU1 reset line to 1 when writing the
>   resets.
> ---
>  drivers/reset/Kconfig        |   7 +++
>  drivers/reset/Makefile       |   1 +
>  drivers/reset/reset-gemini.c | 110 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 118 insertions(+)
>  create mode 100644 drivers/reset/reset-gemini.c
> 
> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> index d21c07ccc94e..361c5515fd48 100644
> --- a/drivers/reset/Kconfig
> +++ b/drivers/reset/Kconfig
> @@ -34,6 +34,13 @@ config RESET_BERLIN
>  	help
>  	  This enables the reset controller driver for Marvell Berlin SoCs.
>  
> +config RESET_GEMINI
> +	bool "Gemini Reset Driver" if COMPILE_TEST
> +	default ARCH_GEMINI
> +	select MFD_SYSCON
> +	help
> +	  This enables the reset controller driver for Cortina Systems Gemini.
> +
>  config RESET_IMX7
>  	bool "i.MX7 Reset Driver" if COMPILE_TEST
>  	default SOC_IMX7D
> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> index 02a74db94339..c711594ebcc0 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -5,6 +5,7 @@ obj-$(CONFIG_ARCH_TEGRA) += tegra/
>  obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
>  obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
>  obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
> +obj-$(CONFIG_RESET_GEMINI) += reset-gemini.o
>  obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
>  obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
>  obj-$(CONFIG_RESET_MESON) += reset-meson.o
> diff --git a/drivers/reset/reset-gemini.c b/drivers/reset/reset-gemini.c
> new file mode 100644
> index 000000000000..a2478997c75b
> --- /dev/null
> +++ b/drivers/reset/reset-gemini.c
> @@ -0,0 +1,110 @@
> +/*
> + * Cortina Gemini Reset controller driver
> + * Copyright (C) 2017 Linus Walleij <linus.walleij at linaro.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset-controller.h>
> +#include <dt-bindings/reset/cortina,gemini-reset.h>
> +
> +/**
> + * struct gemini_reset - gemini reset controller
> + * @map: regmap to access the containing system controller
> + * @rcdev: reset controller device
> + */
> +struct gemini_reset {
> +	struct regmap *map;
> +	struct reset_controller_dev rcdev;
> +};
> +
> +#define GEMINI_GLOBAL_SOFT_RESET 0x0c
> +
> +#define to_gemini_reset(p) \
> +	container_of((p), struct gemini_reset, rcdev)
> +
> +/*
> + * This is a self-deasserting reset controller.
> + */
> +static int gemini_reset(struct reset_controller_dev *rcdev,
> +			unsigned long id)
> +{
> +	struct gemini_reset *gr = to_gemini_reset(rcdev);
> +
> +	/* Manual says to always set BIT 30 (CPU1) to 1 */
> +	return regmap_write(gr->map,
> +			    GEMINI_GLOBAL_SOFT_RESET,
> +			    BIT(GEMINI_RESET_CPU1) | BIT(id));
> +}
> +
> +static int gemini_reset_status(struct reset_controller_dev *rcdev,
> +			     unsigned long id)
> +{
> +	struct gemini_reset *gr = to_gemini_reset(rcdev);
> +	u32 val;
> +	int ret;
> +
> +	ret = regmap_read(gr->map, GEMINI_GLOBAL_SOFT_RESET, &val);
> +	if (ret)
> +		return ret;
> +
> +	return !!(val & BIT(id));
> +}
> +
> +static const struct reset_control_ops gemini_reset_ops = {
> +	.reset = gemini_reset,
> +	.status = gemini_reset_status,
> +};
> +
> +static int gemini_reset_probe(struct platform_device *pdev)
> +{
> +	struct gemini_reset *gr;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	int ret;
> +
> +	gr = devm_kzalloc(dev, sizeof(*gr), GFP_KERNEL);
> +	if (!gr)
> +		return -ENOMEM;
> +
> +	gr->map = syscon_node_to_regmap(np);
> +	if (IS_ERR(gr->map)) {
> +		ret = PTR_ERR(gr->map);
> +		dev_err(dev, "unable to get regmap (%d)", ret);
> +		return ret;
> +	}
> +	gr->rcdev.owner = THIS_MODULE;
> +	gr->rcdev.nr_resets = 32;
> +	gr->rcdev.ops = &gemini_reset_ops;
> +	gr->rcdev.of_node = pdev->dev.of_node;
> +
> +	ret = devm_reset_controller_register(&pdev->dev, &gr->rcdev);
> +	if (ret)
> +		return ret;
> +
> +	dev_info(dev, "registered Gemini reset controller\n");
> +	return 0;
> +}
> +
> +static const struct of_device_id gemini_reset_dt_ids[] = {
> +	{ .compatible = "cortina,gemini-syscon", },
> +	{ /* sentinel */ },
> +};
> +
> +static struct platform_driver gemini_reset_driver = {
> +	.probe	= gemini_reset_probe,
> +	.driver = {
> +		.name		= "gemini-reset",
> +		.of_match_table	= gemini_reset_dt_ids,
> +		.suppress_bind_attrs = true,
> +	},
> +};
> +builtin_platform_driver(gemini_reset_driver);