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Date:   Mon, 17 Sep 2018 11:34:18 +0800
From:   Jisheng Zhang <Jisheng.Zhang@synaptics.com>
To:     Jarkko Nikula <jarkko.nikula@linux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Wolfram Sang <wsa@the-dreams.de>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>
Cc:     linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        <linux-i2c@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        devicetree@vger.kernel.org
Subject: Re: [PATCH v3 3/3] i2c: designware: select gpio/default pin when
 prepare/unprepare recovery
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+ DT maintainers

On Mon, 17 Sep 2018 11:29:49 +0800
Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote:

> On some platforms, the sda/scl pins are muxed with gpio functions, so
> they could be used for recovery. Select the gpio/default pin function
> when prepare/unprepare recovery.
> 
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> ---
>  drivers/i2c/busses/i2c-designware-core.h   |  3 +++
>  drivers/i2c/busses/i2c-designware-master.c | 22 ++++++++++++++++++++++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> index e367b1af4ab2..01d5f01691a4 100644
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -271,6 +271,9 @@ struct dw_i2c_dev {
>  	int			(*init)(struct dw_i2c_dev *dev);
>  	int			mode;
>  	struct i2c_bus_recovery_info rinfo;
> +	struct pinctrl		*pinctrl;
> +	struct pinctrl_state	*pins_default;
> +	struct pinctrl_state	*pins_gpio;
>  };
>  
>  #define ACCESS_SWAP		0x00000001
> diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
> index 94d94b4a9a0d..384d6630366a 100644
> --- a/drivers/i2c/busses/i2c-designware-master.c
> +++ b/drivers/i2c/busses/i2c-designware-master.c
> @@ -17,6 +17,7 @@
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
>  #include <linux/module.h>
> +#include <linux/pinctrl/consumer.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/reset.h>
>  
> @@ -629,6 +630,9 @@ static void i2c_dw_prepare_recovery(struct i2c_adapter *adap)
>  {
>  	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
>  
> +	if (dev->pinctrl && dev->pins_gpio)
> +		pinctrl_select_state(dev->pinctrl, dev->pins_gpio);
> +
>  	i2c_dw_disable(dev);
>  	reset_control_assert(dev->rst);
>  	i2c_dw_prepare_clk(dev, false);
> @@ -641,6 +645,9 @@ static void i2c_dw_unprepare_recovery(struct i2c_adapter *adap)
>  	i2c_dw_prepare_clk(dev, true);
>  	reset_control_deassert(dev->rst);
>  	i2c_dw_init_master(dev);
> +
> +	if (dev->pinctrl && dev->pins_default)
> +		pinctrl_select_state(dev->pinctrl, dev->pins_default);
>  }
>  
>  static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
> @@ -648,6 +655,8 @@ static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
>  	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
>  	struct i2c_adapter *adap = &dev->adapter;
>  	struct gpio_desc *gpio;
> +	struct pinctrl *pinctrl;
> +	struct pinctrl_state *s;
>  	int r;
>  
>  	gpio = devm_gpiod_get(dev->dev, "scl", GPIOD_OUT_HIGH);
> @@ -664,6 +673,19 @@ static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
>  		return PTR_ERR(gpio);
>  	rinfo->sda_gpiod = gpio;
>  
> +	pinctrl = devm_pinctrl_get(dev->dev);
> +	if (PTR_ERR(pinctrl) == -EPROBE_DEFER)
> +		return -EPROBE_DEFER;
> +	if (!IS_ERR_OR_NULL(pinctrl)) {
> +		dev->pinctrl = pinctrl;
> +		s = pinctrl_lookup_state(pinctrl, PINCTRL_STATE_DEFAULT);
> +		if (!IS_ERR_OR_NULL(s))
> +			dev->pins_default = s;
> +		s = pinctrl_lookup_state(pinctrl, "gpio");
> +		if (!IS_ERR_OR_NULL(s))
> +			dev->pins_gpio = s;
> +	}
> +
>  	rinfo->recover_bus = i2c_generic_scl_recovery;
>  	rinfo->prepare_recovery = i2c_dw_prepare_recovery;
>  	rinfo->unprepare_recovery = i2c_dw_unprepare_recovery;