Re: [PATCH v3 1/2] phy: Add a driver for simple phy

[Kishon Vijay Abraham I]

Hi,

On Friday 29 January 2016 01:22 AM, Alban Bedel wrote:
> This driver is meant to take care of all trivial phys that don't need
> any special configuration, it just enable a regulator, a clock and
> deassert a reset. A public API is also included to allow re-using the
> code in other drivers.
> 
> Signed-off-by: Alban Bedel <albeu@xxxxxxx>
> ---

please also include what changed from the previous versions here or in the
cover letter.
>  drivers/phy/Kconfig        |  12 +++
>  drivers/phy/Makefile       |   1 +
>  drivers/phy/phy-simple.c   | 204 +++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/phy/simple.h |  39 +++++++++
>  4 files changed, 256 insertions(+)
>  create mode 100644 drivers/phy/phy-simple.c
>  create mode 100644 include/linux/phy/simple.h
> 
> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> index e7e117d..efbaee4 100644
> --- a/drivers/phy/Kconfig
> +++ b/drivers/phy/Kconfig
> @@ -125,6 +125,18 @@ config PHY_RCAR_GEN3_USB2
>  	help
>  	  Support for USB 2.0 PHY found on Renesas R-Car generation 3 SoCs.
>  
> +config PHY_SIMPLE
> +	tristate
> +	select GENERIC_PHY
> +	help
> +
> +config PHY_SIMPLE_PDEV
> +	tristate "Simple PHY driver"
> +	select PHY_SIMPLE
> +	help
> +	  A PHY driver for simple devices that only need a regulator, clock
> +	  and reset for power up and shutdown.
> +
>  config OMAP_CONTROL_PHY
>  	tristate "OMAP CONTROL PHY Driver"
>  	depends on ARCH_OMAP2PLUS || COMPILE_TEST
> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
> index c80f09d..1cc7268 100644
> --- a/drivers/phy/Makefile
> +++ b/drivers/phy/Makefile
> @@ -26,6 +26,7 @@ obj-$(CONFIG_PHY_EXYNOS5250_SATA)	+= phy-exynos5250-sata.o
>  obj-$(CONFIG_PHY_HIX5HD2_SATA)		+= phy-hix5hd2-sata.o
>  obj-$(CONFIG_PHY_HI6220_USB)		+= phy-hi6220-usb.o
>  obj-$(CONFIG_PHY_MT65XX_USB3)		+= phy-mt65xx-usb3.o
> +obj-$(CONFIG_PHY_SIMPLE)		+= phy-simple.o
>  obj-$(CONFIG_PHY_SUN4I_USB)		+= phy-sun4i-usb.o
>  obj-$(CONFIG_PHY_SUN9I_USB)		+= phy-sun9i-usb.o
>  obj-$(CONFIG_PHY_SAMSUNG_USB2)		+= phy-exynos-usb2.o
> diff --git a/drivers/phy/phy-simple.c b/drivers/phy/phy-simple.c
> new file mode 100644
> index 0000000..013f846
> --- /dev/null
> +++ b/drivers/phy/phy-simple.c
> @@ -0,0 +1,204 @@
> +/*
> + * Copyright (C) 2015 Alban Bedel <albeu@xxxxxxx>

2016?
> + *
> + * 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/module.h>
> +#include <linux/of_device.h>
> +#include <linux/phy/simple.h>
> +#include <linux/clk.h>
> +#include <linux/reset.h>
> +
> +int simple_phy_power_on(struct phy *phy)
> +{
> +	struct simple_phy *sphy = phy_get_drvdata(phy);
> +	int err;
> +
> +	if (sphy->regulator) {
> +		err = regulator_enable(sphy->regulator);
> +		if (err)
> +			return err;
> +	}

phy_power_on already enables the regulator, so this might be redundant. A
simple PHY can have multiple regulators?

Also this doesn't have reference count. I think we should try to reuse the
existing phy_* APIs for simple PHY.
> +
> +	if (sphy->clk) {
> +		err = clk_prepare_enable(sphy->clk);
> +		if (err)
> +			goto regulator_disable;
> +	}

how do we enable multiple clocks?
> +
> +	if (sphy->reset) {
> +		err = reset_control_deassert(sphy->reset);
> +		if (err)
> +			goto clock_disable;
> +	}
> +
> +	return 0;
> +
> +clock_disable:
> +	if (sphy->clk)
> +		clk_disable_unprepare(sphy->clk);
> +regulator_disable:
> +	if (sphy->regulator)
> +		WARN_ON(regulator_disable(sphy->regulator));
> +
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(simple_phy_power_on);
> +
> +int simple_phy_power_off(struct phy *phy)
> +{
> +	struct simple_phy *sphy = phy_get_drvdata(phy);
> +	int err;
> +
> +	if (sphy->reset) {
> +		err = reset_control_assert(sphy->reset);
> +		if (err)
> +			return err;
> +	}
> +
> +	if (sphy->clk)
> +		clk_disable_unprepare(sphy->clk);
> +
> +	if (sphy->regulator) {
> +		err = regulator_disable(sphy->regulator);
> +		if (err)
> +			goto clock_enable;
> +	}
> +
> +	return 0;
> +
> +clock_enable:
> +	if (sphy->clk)
> +		WARN_ON(clk_prepare_enable(sphy->clk));
> +	if (sphy->reset)
> +		WARN_ON(reset_control_deassert(sphy->reset));
> +
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(simple_phy_power_off);
> +
> +static const struct phy_ops simple_phy_ops = {
> +	.power_on	= simple_phy_power_on,
> +	.power_off	= simple_phy_power_off,
> +	.owner		= THIS_MODULE,
> +};
> +
> +struct phy *devm_simple_phy_create(struct device *dev,
> +				const struct simple_phy_desc *desc,
> +				struct simple_phy *sphy)
> +{
> +	struct phy *phy;
> +
> +	if (!dev || !desc)
> +		return ERR_PTR(-EINVAL);
> +
> +	if (!sphy) {
> +		sphy = devm_kzalloc(dev, sizeof(*sphy), GFP_KERNEL);
> +		if (!sphy)
> +			return ERR_PTR(-ENOMEM);
> +	}
> +
> +	if (!IS_ERR_OR_NULL(desc->regulator)) {
> +		sphy->regulator = devm_regulator_get(dev, desc->regulator);
> +		if (IS_ERR(sphy->regulator)) {
> +			if (PTR_ERR(sphy->regulator) == -ENOENT)
> +				sphy->regulator = NULL;
> +			else
> +				return ERR_PTR(PTR_ERR(sphy->regulator));
> +		}
> +	}
> +
> +	if (!IS_ERR(desc->clk)) {
> +		sphy->clk = devm_clk_get(dev, desc->clk);
> +		if (IS_ERR(sphy->clk)) {
> +			if (PTR_ERR(sphy->clk) == -ENOENT)
> +				sphy->clk = NULL;
> +			else
> +				return ERR_PTR(PTR_ERR(sphy->clk));
> +		}
> +	}
> +
> +	if (!IS_ERR(desc->reset)) {
> +		sphy->reset = devm_reset_control_get(dev, desc->reset);
> +		if (IS_ERR(sphy->reset)) {
> +			int err = PTR_ERR(sphy->reset);
> +
> +			if (err == -ENOENT || err == -ENOTSUPP)
> +				sphy->reset = NULL;
> +			else
> +				return ERR_PTR(err);
> +		}
> +	}
> +
> +	phy = devm_phy_create(dev, NULL, desc->ops ?: &simple_phy_ops);
> +	if (IS_ERR(phy))
> +		return ERR_PTR(PTR_ERR(phy));
> +
> +	phy_set_drvdata(phy, sphy);
> +
> +	return phy;
> +}
> +EXPORT_SYMBOL_GPL(devm_simple_phy_create);
> +
> +#ifdef CONFIG_PHY_SIMPLE_PDEV
> +#ifdef CONFIG_OF
> +/* Default config, no regulator, default clock and reset if any */
> +static const struct simple_phy_desc simple_phy_default_desc = {};
> +
> +static const struct of_device_id simple_phy_of_match[] = {
> +	{ .compatible = "simple-phy", .data = &simple_phy_default_desc },

the compatible string should be documented.

Thanks
Kishon