[2/2] reset: Add basic single-register reset driver

Message ID 20170526033214.8081-3-joel@jms.id.au
State New
Headers show
Series
  • reset: Basic reset controller
Related show

Commit Message

Joel Stanley May 26, 2017, 3:32 a.m.
This driver is a basic single-register reset controller driver that
supports clearing a single bit in a register.

Signed-off-by: Joel Stanley <joel@jms.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

-- 
2.11.0

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Comments

Andy Shevchenko May 27, 2017, 3:11 p.m. | #1
On Fri, May 26, 2017 at 6:32 AM, Joel Stanley <joel@jms.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@jms.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@jms.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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Andy Shevchenko May 29, 2017, 3:41 p.m. | #2
On Mon, May 29, 2017 at 1:24 PM, Joel Stanley <joel@jms.id.au> wrote:
> On Sun, May 28, 2017 at 12:41 AM, Andy Shevchenko

> <andy.shevchenko@gmail.com> wrote:

>> On Fri, May 26, 2017 at 6:32 AM, Joel Stanley <joel@jms.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.

>

> Do we have a GPIO based one already? I couldn't find it.


No, we haven't.

> Having a think, it would be a very similar looking driver, but with

> little shared code. The context struct would contain a gpio pointer

> instead of regmap, probe would request a GPIO instead of a regmap and

> the assert/deassert/status callbacks would be gpiod_ calls.

>

> Given this is four of the four functions in this driver, do you think would be

> better off with two small drivers?


Fair enough.
Sounds like independent drivers for now is a good approach, though
it's up to maintainer.

-- 
With Best Regards,
Andy Shevchenko
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Patch hide | download patch | download mbox

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@jms.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);