Date:	Thu, 26 Jun 2014 09:38:41 +0800
From:	Chen-Yu Tsai <wens@...e.org>
To:	Feng Kan <fkan@....com>
Cc:	dbaryshkov@...il.com, catalin.marinas@....com, dwmw2@...radead.org,
	Arnd Bergmann <arnd@...db.de>,
	devicetree <devicetree@...r.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	linux-kernel <linux-kernel@...r.kernel.org>, patches@....com
Subject: Re: [PATCH V7 1/6] power: reset: Add generic SYSCON register mapped reset

On Thu, Jun 26, 2014 at 7:03 AM, Feng Kan <fkan@....com> wrote:
> Add a generic SYSCON register mapped reset mechanism.
>
> Signed-off-by: Feng Kan <fkan@....com>
> ---
>  drivers/power/reset/Kconfig         |  6 +++
>  drivers/power/reset/Makefile        |  1 +
>  drivers/power/reset/syscon-reboot.c | 91 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 98 insertions(+)
>  create mode 100644 drivers/power/reset/syscon-reboot.c
>
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index bdcf517..7035236 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -80,3 +80,9 @@ config POWER_RESET_KEYSTONE
>         help
>           Reboot support for the KEYSTONE SoCs.
>
> +config POWER_RESET_SYSCON
> +       bool "Generic SYSCON regmap reset driver"
> +       depends on ARCH_XGENE

If this is supposed to be generic, why are you depending on
a certain platform?


ChenYu

> +       depends on POWER_RESET && MFD_SYSCON
> +       help
> +         Reboot support for generic SYSCON mapped register reset.
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index dde2e8b..b1b5ab3 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -8,3 +8,4 @@ obj-$(CONFIG_POWER_RESET_SUN6I) += sun6i-reboot.o
>  obj-$(CONFIG_POWER_RESET_VEXPRESS) += vexpress-poweroff.o
>  obj-$(CONFIG_POWER_RESET_XGENE) += xgene-reboot.o
>  obj-$(CONFIG_POWER_RESET_KEYSTONE) += keystone-reset.o
> +obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o
> diff --git a/drivers/power/reset/syscon-reboot.c b/drivers/power/reset/syscon-reboot.c
> new file mode 100644
> index 0000000..9c15ba5
> --- /dev/null
> +++ b/drivers/power/reset/syscon-reboot.c
> @@ -0,0 +1,91 @@
> +/*
> + * Generic Syscon Reboot Driver
> + *
> + * Copyright (c) 2013, Applied Micro Circuits Corporation
> + * Author: Feng Kan <fkan@....com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +#include <linux/io.h>
> +#include <linux/of_device.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/stat.h>
> +#include <linux/slab.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +#include <linux/reboot.h>
> +#include <asm/system_misc.h>
> +
> +struct syscon_reboot_context {
> +       struct regmap *map;
> +       u32 offset;
> +       u32 mask;
> +};
> +
> +static struct syscon_reboot_context *syscon_reboot_ctx;
> +
> +static void syscon_restart(enum reboot_mode reboot_mode, const char *cmd)
> +{
> +       struct syscon_reboot_context *ctx = syscon_reboot_ctx;
> +       unsigned long timeout;
> +
> +       /* Issue the reboot */
> +       if (ctx->map)
> +               regmap_write(ctx->map, ctx->offset, ctx->mask);
> +
> +       timeout = jiffies + HZ;
> +       while (time_before(jiffies, timeout))
> +               cpu_relax();
> +
> +       pr_emerg("Unable to restart system\n");
> +}
> +
> +static int syscon_reboot_probe(struct platform_device *pdev)
> +{
> +       struct syscon_reboot_context *ctx;
> +       struct device *dev = &pdev->dev;
> +
> +       ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
> +       if (!ctx) {
> +               dev_err(&pdev->dev, "out of memory for context\n");
> +               return -ENOMEM;
> +       }
> +
> +       ctx->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
> +       if (IS_ERR(ctx->map))
> +               return PTR_ERR(ctx->map);
> +
> +       if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset))
> +               return -EINVAL;
> +
> +       if (of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask))
> +               return -EINVAL;
> +
> +       arm_pm_restart = syscon_restart;
> +       syscon_reboot_ctx = ctx;
> +
> +       return 0;
> +}
> +
> +static struct of_device_id syscon_reboot_of_match[] = {
> +       { .compatible = "syscon-reboot" },
> +       {}
> +};
> +
> +static struct platform_driver syscon_reboot_driver = {
> +       .probe = syscon_reboot_probe,
> +       .driver = {
> +               .name = "syscon-reboot",
> +               .of_match_table = syscon_reboot_of_match,
> +       },
> +};
> +module_platform_driver(syscon_reboot_driver);
> --
> 1.9.1
>
>
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