From mboxrd@z Thu Jan  1 00:00:00 1970
From: zhangfei <zhangfei.gao@linaro.org>
Subject: Re: [PATCH] i2c: designware: add reset interface
Date: Thu, 15 Dec 2016 16:56:10 +0800
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 <20161213203457.GB2889@katana> <1481742050.9552.5.camel@linux.intel.com>
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To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Wolfram Sang <wsa@the-dreams.de>
Cc: linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, Jarkko Nikula <jarkko.nikula@linux.intel.com>, Mika Westerberg <mika.westerberg@linux.intel.com>



On 2016年12月15日 03:00, Andy Shevchenko wrote:
> On Tue, 2016-12-13 at 21:34 +0100, Wolfram Sang wrote:
>> 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@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);
> Do we care about EPROBE_DEFER?
>
> Perhaps on error path we need to assert it.
>
> And I guess it should be devm_reset_control_get_optional().

Thanks Andy
Good suggestion, will update accordingly.

Thanks