[PATCH v2] i2c: designware: add reset interface

[Ramiro Oliveira]

Hi Andy and Zhangfei

On 12/15/2016 12:33 PM, Andy Shevchenko wrote:
> On Thu, 2016-12-15 at 16:59 +0800, Zhangfei Gao wrote:
>> Some platforms like hi3660 need do reset first to allow accessing
>> registers
> 
> Patch itself looks good, but would be nice to have it tested.
> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
> 

I tested the patch and it's working for the ARC architecture.

>>
>> Signed-off-by: Zhangfei Gao <zhangfei.gao at linaro.org>
>> ---
>>  drivers/i2c/busses/i2c-designware-core.h    |  1 +
>>  drivers/i2c/busses/i2c-designware-platdrv.c | 28
>> ++++++++++++++++++++++++----
>>  2 files changed, 25 insertions(+), 4 deletions(-)
>>
>> 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..e9016ae 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 +177,14 @@ static int dw_i2c_plat_probe(struct
>> platform_device *pdev)
>>  	dev->irq = irq;
>>  	platform_set_drvdata(pdev, dev);
>>  
>> +	dev->rst = devm_reset_control_get_optional(&pdev->dev, NULL);

devm_reset_control_get_optional() is deprecated as explained in linux/reset.h,
you should use devm_reset_control_get_optional_exclusive() or
devm_reset_control_get_optional_shared() instead, as applicable.

I submitted a similar patch earlier today and I made the same mistake.

>> +	if (IS_ERR(dev->rst)) {
>> +		if (PTR_ERR(dev->rst) == -EPROBE_DEFER)
>> +			return -EPROBE_DEFER;
>> +	} else {
>> +		reset_control_deassert(dev->rst);
>> +	}
>> +
>>  	/* fast mode by default because of legacy reasons */
>>  	dev->clk_freq = 400000;
>>  
>> @@ -207,12 +216,13 @@ static int dw_i2c_plat_probe(struct
>> platform_device *pdev)
>>  	    && dev->clk_freq != 1000000 && dev->clk_freq != 3400000)
>> {
>>  		dev_err(&pdev->dev,
>>  			"Only 100kHz, 400kHz, 1MHz and 3.4MHz
>> supported");
>> -		return -EINVAL;
>> +		r = -EINVAL;
>> +		goto exit_reset;
>>  	}
>>  
>>  	r = i2c_dw_eval_lock_support(dev);
>>  	if (r)
>> -		return r;
>> +		goto exit_reset;
>>  
>>  	dev->functionality =
>>  		I2C_FUNC_I2C |
>> @@ -270,10 +280,18 @@ static int dw_i2c_plat_probe(struct
>> platform_device *pdev)
>>  	}
>>  
>>  	r = i2c_dw_probe(dev);
>> -	if (r && !dev->pm_runtime_disabled)
>> -		pm_runtime_disable(&pdev->dev);
>> +	if (r)
>> +		goto exit_probe;
>>  
>>  	return r;
>> +
>> +exit_probe:
>> +	if (!dev->pm_runtime_disabled)
>> +		pm_runtime_disable(&pdev->dev);
>> +exit_reset:
>> +	if (!IS_ERR_OR_NULL(dev->rst))
>> +		reset_control_assert(dev->rst);
>> +	return r;
>>  }
>>  
>>  static int dw_i2c_plat_remove(struct platform_device *pdev)
>> @@ -290,6 +308,8 @@ static int dw_i2c_plat_remove(struct
>> platform_device *pdev)
>>  	pm_runtime_put_sync(&pdev->dev);
>>  	if (!dev->pm_runtime_disabled)
>>  		pm_runtime_disable(&pdev->dev);
>> +	if (!IS_ERR_OR_NULL(dev->rst))
>> +		reset_control_assert(dev->rst);
>>  
>>  	return 0;
>>  }
> 
Tested-by: Ramiro Oliveira <ramiro.oliveira at synopsys.com>