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Date: Sat, 27 May 2017 18:11:16 +0300
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Joel Stanley <joel@....id.au>
Cc: Philipp Zabel <p.zabel@...gutronix.de>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
devicetree <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Andrew Jeffery <andrew@...id.au>
Subject: Re: [PATCH 2/2] reset: Add basic single-register reset driver
On Fri, May 26, 2017 at 6:32 AM, Joel Stanley <joel@....id.au> wrote:
> This driver is a basic single-register reset controller driver that
> supports clearing a single bit in a register.
>
While this makes sense, I'm wondering if there can be generic
interface for this from which we can derive this one and GPIO-based
one.
> Signed-off-by: Joel Stanley <joel@....id.au>
> ---
> drivers/reset/Kconfig | 6 +++
> drivers/reset/Makefile | 1 +
> drivers/reset/reset-basic.c | 109 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 116 insertions(+)
> create mode 100644 drivers/reset/reset-basic.c
>
> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> index d21c07ccc94e..980cda887dfe 100644
> --- a/drivers/reset/Kconfig
> +++ b/drivers/reset/Kconfig
> @@ -28,6 +28,12 @@ config RESET_ATH79
> This enables the ATH79 reset controller driver that supports the
> AR71xx SoC reset controller.
>
> +config RESET_BASIC
> + bool "Basic Reset Driver"
> + help
> + This enables a basic single-register reset controller driver that
> + supports clearing a single bit in a register.
> +
> config RESET_BERLIN
> bool "Berlin Reset Driver" if COMPILE_TEST
> default ARCH_BERLIN
> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> index 02a74db94339..e8e8869e098d 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -4,6 +4,7 @@ obj-$(CONFIG_ARCH_STI) += sti/
> obj-$(CONFIG_ARCH_TEGRA) += tegra/
> obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
> obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
> +obj-$(CONFIG_RESET_BASIC) += reset-basic.o
> obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
> obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
> obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
> diff --git a/drivers/reset/reset-basic.c b/drivers/reset/reset-basic.c
> new file mode 100644
> index 000000000000..62a676de9f62
> --- /dev/null
> +++ b/drivers/reset/reset-basic.c
> @@ -0,0 +1,109 @@
> +/*
> + * Copyright 2017 IBM Corperation
> + *
> + * Joel Stanley <joel@....id.au>
> + *
> + * 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.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/reset-controller.h>
> +
> +#define to_basic_reset_priv(p) \
> + container_of((p), struct basic_reset_priv, rcdev)
> +
> +struct basic_reset_priv {
> + struct regmap *regmap;
> + struct reset_controller_dev rcdev;
> + u32 reg;
> +};
> +
> +static int basic_reset_assert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct basic_reset_priv *priv = to_basic_reset_priv(rcdev);
> + u32 mask = BIT(id);
> +
> + regmap_update_bits(priv->regmap, priv->reg, mask, mask);
> +
> + return 0;
> +}
> +
> +static int basic_reset_deassert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct basic_reset_priv *priv = to_basic_reset_priv(rcdev);
> + u32 mask = BIT(id);
> +
> + regmap_update_bits(priv->regmap, priv->reg, mask, 0);
> +
> + return 0;
> +}
> +
> +static int basic_reset_status(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct basic_reset_priv *priv = to_basic_reset_priv(rcdev);
> + u32 mask = BIT(id);
> + u32 val;
> +
> + regmap_read(priv->regmap, priv->reg, &val);
> +
> + return !!(val & mask);
> +}
> +
> +static const struct reset_control_ops basic_reset_ops = {
> + .assert = basic_reset_assert,
> + .deassert = basic_reset_deassert,
> + .status = basic_reset_status,
> +};
> +
> +static int basic_reset_probe(struct platform_device *pdev)
> +{
> + struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
> + struct basic_reset_priv *priv;
> + int ret;
> +
> + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->regmap = syscon_node_to_regmap(parent_np);
> + of_node_put(parent_np);
> + if (IS_ERR(priv->regmap))
> + return PTR_ERR(priv->regmap);
> +
> + ret = of_property_read_u32(pdev->dev.of_node, "reg", &priv->reg);
> + if (ret)
> + return ret;
> +
> + priv->rcdev.owner = THIS_MODULE;
> + priv->rcdev.ops = &basic_reset_ops;
> + priv->rcdev.of_node = pdev->dev.of_node;
> + priv->rcdev.nr_resets = 32;
> +
> + return reset_controller_register(&priv->rcdev);
> +}
> +
> +static const struct of_device_id basic_reset_dt_match[] = {
> + { .compatible = "reset-basic" },
> + { },
> +};
> +
> +static struct platform_driver basic_reset_driver = {
> + .probe = basic_reset_probe,
> + .driver = {
> + .name = "basic-reset",
> + .of_match_table = basic_reset_dt_match,
> + },
> +};
> +builtin_platform_driver(basic_reset_driver);
> --
> 2.11.0
>
--
With Best Regards,
Andy Shevchenko
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