[PATCH] i2c: designware: add reset interface

[Wolfram Sang]

On Tue, Nov 22, 2016 at 12:41:40PM +0800, Zhangfei Gao wrote:
> Some platforms like hi3660 need do reset first to allow accessing registers
> 
> Signed-off-by: Zhangfei Gao <zhangfei.gao at linaro.org>

Adding designware maintainers to CC...

> ---
>  drivers/i2c/busses/i2c-designware-core.h    | 1 +
>  drivers/i2c/busses/i2c-designware-platdrv.c | 5 +++++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> index 0d44d2a..94b14fa 100644
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -80,6 +80,7 @@ struct dw_i2c_dev {
>  	void __iomem		*base;
>  	struct completion	cmd_complete;
>  	struct clk		*clk;
> +	struct reset_control	*rst;
>  	u32			(*get_clk_rate_khz) (struct dw_i2c_dev *dev);
>  	struct dw_pci_controller *controller;
>  	int			cmd_err;
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index 0b42a12..fd80e58 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -38,6 +38,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/property.h>
>  #include <linux/io.h>
> +#include <linux/reset.h>
>  #include <linux/slab.h>
>  #include <linux/acpi.h>
>  #include <linux/platform_data/i2c-designware.h>
> @@ -176,6 +177,10 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
>  	dev->irq = irq;
>  	platform_set_drvdata(pdev, dev);
>  
> +	dev->rst = devm_reset_control_get(&pdev->dev, NULL);
> +	if (!IS_ERR(dev->rst))
> +		reset_control_reset(dev->rst);
> +
>  	/* fast mode by default because of legacy reasons */
>  	dev->clk_freq = 400000;
>  
> -- 
> 2.7.4
> 
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