linux-kernel - Re: [PATCH v2 4/4] power: reset: Add new driver for RZ/V2M PWC poweroff

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Message-ID: <20230102192204.hcqhtrl5gbpuqhyd@mercury.elektranox.org>
Date:   Mon, 2 Jan 2023 20:22:04 +0100
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Fabrizio Castro <fabrizio.castro.jz@...esas.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Lee Jones <lee@...nel.org>, linux-gpio@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org,
        Chris Paterson <Chris.Paterson2@...esas.com>,
        Biju Das <biju.das@...renesas.com>,
        linux-renesas-soc@...r.kernel.org,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Jacopo Mondi <jacopo@...ndi.org>
Subject: Re: [PATCH v2 4/4] power: reset: Add new driver for RZ/V2M PWC
 poweroff

Hi,

On Wed, Dec 21, 2022 at 09:09:17PM +0000, Fabrizio Castro wrote:
> The RZ/V2M PWC IP controls external power supplies and therefore
> can turn the power supplies off when powering down the system.
> 
> Add driver to poweroff the system.
> 
> Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@...esas.com>
> ---

Acked-by: Sebastian Reichel <sebastian.reichel@...labora.com>

-- Sebastian

> 
> v1->v2: Dropped OF match table and syscon as a result of the change in
>         DT model
> 
>  drivers/power/reset/Kconfig              |  9 ++++
>  drivers/power/reset/Makefile             |  1 +
>  drivers/power/reset/rzv2m-pwc-poweroff.c | 67 ++++++++++++++++++++++++
>  3 files changed, 77 insertions(+)
>  create mode 100644 drivers/power/reset/rzv2m-pwc-poweroff.c
> 
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index a8c46ba5878f..1fcf691ae68e 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -303,4 +303,13 @@ config POWER_MLXBF
>  	help
>  	  This driver supports reset or low power mode handling for Mellanox BlueField.
>  
> +config POWER_RESET_RZV2M_PWC
> +	tristate "Renesas RZ/V2M PWC Power OFF support"
> +	depends on MFD_RZV2M_PWC_CORE || COMPILE_TEST
> +	help
> +	  The RZ/V2M PWC IP controls external power supplies and therefore can
> +	  turn the power supplies off when powering down the system.
> +	  Enable this driver when PWC is in control of the system power supplies
> +	  and it's the preferred way to shutdown the system.
> +
>  endif
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index 0a39424fc558..f05a8abff2eb 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -36,3 +36,4 @@ obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o
>  obj-$(CONFIG_POWER_RESET_SC27XX) += sc27xx-poweroff.o
>  obj-$(CONFIG_NVMEM_REBOOT_MODE) += nvmem-reboot-mode.o
>  obj-$(CONFIG_POWER_MLXBF) += pwr-mlxbf.o
> +obj-$(CONFIG_POWER_RESET_RZV2M_PWC) += rzv2m-pwc-poweroff.o
> diff --git a/drivers/power/reset/rzv2m-pwc-poweroff.c b/drivers/power/reset/rzv2m-pwc-poweroff.c
> new file mode 100644
> index 000000000000..f5bc383c22e1
> --- /dev/null
> +++ b/drivers/power/reset/rzv2m-pwc-poweroff.c
> @@ -0,0 +1,67 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2022 Renesas Electronics Corporation
> + *
> + * Reset driver for Renesas RZ/V2M External Power Sequence Controller (PWC)
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +#include "../../mfd/rzv2m-pwc.h"
> +
> +#define PWC_PWCRST_RSTSOFTAX		0x1
> +#define PWC_PWCCKEN_ENGCKMAIN		0x1
> +#define PWC_PWCCTL_PWOFF		0x1
> +
> +struct rzv2m_pwc_poweroff_priv {
> +	void __iomem *base;
> +	struct device *dev;
> +};
> +
> +static int rzv2m_pwc_poweroff(struct sys_off_data *data)
> +{
> +	struct rzv2m_pwc_poweroff_priv *priv =
> +		(struct rzv2m_pwc_poweroff_priv *)data->cb_data;
> +
> +	writel(PWC_PWCRST_RSTSOFTAX, priv->base + PWC_PWCRST);
> +	writel(PWC_PWCCKEN_ENGCKMAIN, priv->base + PWC_PWCCKEN);
> +	writel(PWC_PWCCTL_PWOFF, priv->base + PWC_PWCCTL);
> +
> +	mdelay(150);
> +
> +	dev_err(priv->dev, "Failed to power off the system");
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static int rzv2m_pwc_poweroff_probe(struct platform_device *pdev)
> +{
> +	struct rzv2m_pwc_priv *pdata = dev_get_drvdata(pdev->dev.parent);
> +	struct rzv2m_pwc_poweroff_priv *priv;
> +
> +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->base = pdata->base;
> +	priv->dev = &pdev->dev;
> +
> +	return devm_register_power_off_handler(&pdev->dev, rzv2m_pwc_poweroff,
> +					       priv);
> +}
> +
> +static struct platform_driver rzv2m_pwc_poweroff_driver = {
> +	.probe = rzv2m_pwc_poweroff_probe,
> +	.driver = {
> +		.name = "rzv2m_pwc_poweroff",
> +	},
> +};
> +module_platform_driver(rzv2m_pwc_poweroff_driver);
> +
> +MODULE_ALIAS("platform:rzv2m_pwc_poweroff");
> +MODULE_SOFTDEP("pre: rzv2m_pwc");
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Fabrizio Castro <castro.fabrizio.jz@...esas.com>");
> +MODULE_DESCRIPTION("Renesas RZ/V2M PWC power OFF driver");
> -- 
> 2.34.1
> 

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