linux-kernel - Re: [PATCH] rtc: omap: Support scratch registers

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Date:   Wed, 8 Nov 2017 11:30:45 +0530
From:   Keerthy <j-keerthy@...com>
To:     Sekhar Nori <nsekhar@...com>,
        Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
        <linux-rtc@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>,
        Linux OMAP List <linux-omap@...r.kernel.org>
Subject: Re: [PATCH] rtc: omap: Support scratch registers



On Monday 06 November 2017 12:29 PM, Keerthy wrote:
> 
> 
> On Monday 06 November 2017 12:25 PM, Sekhar Nori wrote:
>> + linux omap list
>>
>> On Tuesday 31 October 2017 09:57 PM, Alexandre Belloni wrote:
>>> Register an nvmem device to expose the 3 scratch registers (total of 12
>>> bytes) to both userspace and kernel space.
>>>
>>> Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
>>
>> Looks good to me.
>>
>> Reviewed-by: Sekhar Nori <nsekhar@...com>
>>
>> Curious on what you are using these registers for.
> 
> This is in response to this:
> https://patchwork.kernel.org/patch/9684955/

Couple of minor comments below. Apart from that:

Tested-by: Keerthy <j-keerthy@...com>
Reviewed-by: Keerthy <j-keerthy@...com>

> 
> 
>>
>> Thanks,
>> Sekhar
>>
>>> ---
>>>  drivers/rtc/rtc-omap.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 45 insertions(+)
>>>
>>> diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
>>> index d56d937966dc..1d666ac9ef70 100644
>>> --- a/drivers/rtc/rtc-omap.c
>>> +++ b/drivers/rtc/rtc-omap.c
>>> @@ -70,6 +70,10 @@
>>>  #define OMAP_RTC_COMP_MSB_REG		0x50
>>>  #define OMAP_RTC_OSC_REG		0x54
>>>  
>>> +#define OMAP_RTC_SCRATCH0_REG		0x60
>>> +#define OMAP_RTC_SCRATCH1_REG		0x64
>>> +#define OMAP_RTC_SCRATCH2_REG		0x68
>>> +
>>>  #define OMAP_RTC_KICK0_REG		0x6c
>>>  #define OMAP_RTC_KICK1_REG		0x70
>>>  
>>> @@ -667,6 +671,45 @@ static struct pinctrl_desc rtc_pinctrl_desc = {
>>>  	.owner = THIS_MODULE,
>>>  };
>>>  
>>> +static int omap_rtc_scratch_read(void *priv, unsigned int offset, void *_val,
>>> +				 size_t bytes)
>>> +{
>>> +	struct omap_rtc	*rtc = priv;
>>> +	u32 *val = _val;
>>> +	int i;
>>> +
>>> +	for (i = 0; i < bytes / 4; i++)
>>> +		val[i] = rtc_readl(rtc,
>>> +				   OMAP_RTC_SCRATCH0_REG + offset + (i * 4));

Can the offset be the Scratch register number instead of bytes offset?
More intuitive to me.

So that one can request using offset as 0, 1, 2 instead of 0, 4, 8?

The above can be:
rtc_readl(rtc, OMAP_RTC_SCRATCH0_REG + (offset + i) * 4), val[i]);


>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int omap_rtc_scratch_write(void *priv, unsigned int offset, void *_val,
>>> +				  size_t bytes)
>>> +{
>>> +	struct omap_rtc	*rtc = priv;
>>> +	u32 *val = _val;
>>> +	int i;
>>> +
>>> +	rtc->type->unlock(rtc);
>>> +	for (i = 0; i < bytes / 4; i++)
>>> +		rtc_writel(rtc,
>>> +			   OMAP_RTC_SCRATCH0_REG + offset + (i * 4), val[i]);

The above can be:
rtc_writel(rtc, OMAP_RTC_SCRATCH0_REG + (offset + i) * 4), val[i]);

>>> +	rtc->type->lock(rtc);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static struct nvmem_config omap_rtc_nvmem_config = {
>>> +	.name = "omap_rtc_scratch",
>>> +	.word_size = 4,
>>> +	.stride = 4,
>>> +	.size = OMAP_RTC_KICK0_REG - OMAP_RTC_SCRATCH0_REG,
>>> +	.reg_read = omap_rtc_scratch_read,
>>> +	.reg_write = omap_rtc_scratch_write,
>>> +};
>>> +
>>>  static int omap_rtc_probe(struct platform_device *pdev)
>>>  {
>>>  	struct omap_rtc	*rtc;
>>> @@ -804,6 +847,8 @@ static int omap_rtc_probe(struct platform_device *pdev)
>>>  	}
>>>  
>>>  	rtc->rtc->ops = &omap_rtc_ops;
>>> +	omap_rtc_nvmem_config.priv = rtc;
>>> +	rtc->rtc->nvmem_config = &omap_rtc_nvmem_config;
>>>  
>>>  	/* handle periodic and alarm irqs */
>>>  	ret = devm_request_irq(&pdev->dev, rtc->irq_timer, rtc_irq, 0,
>>> -- 
>>> 2.15.0.rc2
>>>
>>
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