linux-kernel - Re: [PATCH v3 3/3] i2c/at91: adopt pinctrl support

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Date:	Sat, 8 Nov 2014 19:03:14 +0100
From:	Wolfram Sang <wsa@...-dreams.de>
To:	Wenyou Yang <wenyou.yang@...el.com>
Cc:	ludovic.desroches@...el.com, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org, nicolas.ferre@...el.com,
	khilman@...nel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 3/3] i2c/at91: adopt pinctrl support

On Fri, Oct 24, 2014 at 02:50:17PM +0800, Wenyou Yang wrote:
> Amend the i2c at91 pin controller to optionally take a pin control
> handle and set the state of the pins to:
> 
> - "default" on boot, resume and before performing an transfer
> - "sleep" on suspend()
> 
> This should make it possible to optimize energy usage for the pins
> both for the suspend/resume cycle
> 
> Signed-off-by: Wenyou Yang <wenyou.yang@...el.com>
> ---
>  drivers/i2c/busses/i2c-at91.c |    7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
> index 6a84a2a..290caf1 100644
> --- a/drivers/i2c/busses/i2c-at91.c
> +++ b/drivers/i2c/busses/i2c-at91.c
> @@ -32,6 +32,7 @@
>  #include <linux/slab.h>
>  #include <linux/platform_data/dma-atmel.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/pinctrl/consumer.h>
>  
>  #define DEFAULT_TWI_CLK_HZ		100000		/* max 400 Kbits/s */
>  #define AT91_I2C_TIMEOUT	msecs_to_jiffies(100)	/* transfer timeout */
> @@ -747,6 +748,8 @@ static int at91_twi_probe(struct platform_device *pdev)
>  	u32 phy_addr;
>  	u32 bus_clk_rate;
>  
> +	pinctrl_pm_select_default_state(&pdev->dev);
> +

Do we really need this in probe? Isn't that default? I'm not sure,
though...

>  	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
>  	if (!dev)
>  		return -ENOMEM;
> @@ -851,6 +854,8 @@ static int at91_twi_runtime_suspend(struct device *dev)
>  
>  	clk_disable_unprepare(twi_dev->clk);
>  
> +	pinctrl_pm_select_sleep_state(dev);
> +
>  	return 0;
>  }
>  
> @@ -858,6 +863,8 @@ static int at91_twi_runtime_resume(struct device *dev)
>  {
>  	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
>  
> +	pinctrl_pm_select_default_state(dev);
> +
>  	return clk_prepare_enable(twi_dev->clk);
>  }
>  
> -- 
> 1.7.9.5
> 

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