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Date: Thu, 21 Jan 2016 11:55:00 -0300
From: Javier Martinez Canillas <javier@....samsung.com>
To: Krzysztof Kozlowski <k.kozlowski@...sung.com>,
linux-kernel@...r.kernel.org
Cc: Kukjin Kim <kgene@...nel.org>, rtc-linux@...glegroups.com,
Chanwoo Choi <cw00.choi@...sung.com>,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
Laxman Dewangan <ldewangan@...dia.com>,
linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH 3/8] rtc: max77686: Use a driver data struct instead
hard-coded values
Hello Krzysztof,
Thanks a lot for your review.
On 01/20/2016 09:45 PM, Krzysztof Kozlowski wrote:
> On 21.01.2016 02:14, Javier Martinez Canillas wrote:
>> The driver has some hard-coded values such as the minimum delay needed
>> before a RTC update or the mask used for the sec/min/hour/etc registers.
>>
>> Use a data structure that contains these values and pass as driver data
>> using the platform device ID table for each device.
>>
>> This allows to make the driver's ops callbacks more generic so other RTC
>> that are similar but don't have the same values can also be supported.
>>
>> Signed-off-by: Javier Martinez Canillas <javier@....samsung.com>
>> ---
>>
>> drivers/rtc/rtc-max77686.c | 47 +++++++++++++++++++++++++++++-----------------
>> 1 file changed, 30 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
>> index ae4d61e7ce4b..441d163dcbeb 100644
>> --- a/drivers/rtc/rtc-max77686.c
>> +++ b/drivers/rtc/rtc-max77686.c
>> @@ -41,8 +41,6 @@
>> #define ALARM_ENABLE_SHIFT 7
>> #define ALARM_ENABLE_MASK (1 << ALARM_ENABLE_SHIFT)
>>
>> -#define MAX77686_RTC_UPDATE_DELAY 16000
>> -
>> enum {
>> RTC_SEC = 0,
>> RTC_MIN,
>> @@ -54,6 +52,11 @@ enum {
>> RTC_NR_TIME
>> };
>>
>> +struct rtc_driver_data {
>
> 1. This is only local structure so maybe: max77686_rtc_driver_data?
>
Agreed.
> 2. Can you put here a comment explaining the purpose of this delay
> (quite generic name) and used units?
>
>> + unsigned long delay;
>
> A comment here - what 'mask'? Generic name so explanation would be welcomed.
>
>> + int mask;
>
> I think this should be u8 to avoid early promotions to int. It is used
> directly with other u8 values. At the end effect of operation is
> promoted to int anyway but using only u8 for operations looks more
> consistent to me.
>
Ok, I added comments for these two fields and used u8 for mask instead.
>> +};
>> +
>> struct max77686_rtc_info {
>> struct device *dev;
>> struct max77686_dev *max77686;
>> @@ -63,6 +66,8 @@ struct max77686_rtc_info {
>>
>> struct regmap *regmap;
>>
>> + struct rtc_driver_data *drv_data;
>
> That may be pointer to const data. Actually not "may be" but
> even "should be" because you allocate later really a const data and you
> are discarding const-ness with cast.
>
Agreed, I missed that before.
>> +
>> int virq;
>> int rtc_24hr_mode;
>> };
>> @@ -72,12 +77,19 @@ enum MAX77686_RTC_OP {
>> MAX77686_RTC_READ,
>> };
>>
>> +static const struct rtc_driver_data max77686_drv_data = {
>> + .delay = 1600,
>> + .mask = 0x7f,
>> +};
>> +
>> static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
>> - int rtc_24hr_mode)
>> + struct max77686_rtc_info *info)
>> {
>> - tm->tm_sec = data[RTC_SEC] & 0x7f;
>> - tm->tm_min = data[RTC_MIN] & 0x7f;
>> - if (rtc_24hr_mode)
>> + int mask = info->drv_data->mask;
>> +
>> + tm->tm_sec = data[RTC_SEC] & mask;
>> + tm->tm_min = data[RTC_MIN] & mask;
>> + if (info->rtc_24hr_mode)
>> tm->tm_hour = data[RTC_HOUR] & 0x1f;
>> else {
>> tm->tm_hour = data[RTC_HOUR] & 0x0f;
>> @@ -86,10 +98,10 @@ static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
>> }
>>
>> /* Only a single bit is set in data[], so fls() would be equivalent */
>> - tm->tm_wday = ffs(data[RTC_WEEKDAY] & 0x7f) - 1;
>> + tm->tm_wday = ffs(data[RTC_WEEKDAY] & mask) - 1;
>> tm->tm_mday = data[RTC_DATE] & 0x1f;
>> tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
>> - tm->tm_year = (data[RTC_YEAR] & 0x7f) + 100;
>> + tm->tm_year = (data[RTC_YEAR] & mask) + 100;
>> tm->tm_yday = 0;
>> tm->tm_isdst = 0;
>> }
>> @@ -117,6 +129,7 @@ static int max77686_rtc_update(struct max77686_rtc_info *info,
>> {
>> int ret;
>> unsigned int data;
>> + unsigned long delay = info->drv_data->delay;
>>
>> if (op == MAX77686_RTC_WRITE)
>> data = 1 << RTC_UDR_SHIFT;
>> @@ -129,9 +142,8 @@ static int max77686_rtc_update(struct max77686_rtc_info *info,
>> dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
>> __func__, ret, data);
>> else {
>> - /* Minimum 16ms delay required before RTC update. */
>> - usleep_range(MAX77686_RTC_UPDATE_DELAY,
>> - MAX77686_RTC_UPDATE_DELAY * 2);
>> + /* Minimum delay required before RTC update. */
>> + usleep_range(delay, delay * 2);
>> }
>>
>> return ret;
>> @@ -156,7 +168,7 @@ static int max77686_rtc_read_time(struct device *dev, struct rtc_time *tm)
>> goto out;
>> }
>>
>> - max77686_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
>> + max77686_rtc_data_to_tm(data, tm, info);
>>
>> ret = rtc_valid_tm(tm);
>>
>> @@ -213,7 +225,7 @@ static int max77686_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
>> goto out;
>> }
>>
>> - max77686_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
>> + max77686_rtc_data_to_tm(data, &alrm->time, info);
>>
>> alrm->enabled = 0;
>> for (i = 0; i < RTC_NR_TIME; i++) {
>> @@ -260,7 +272,7 @@ static int max77686_rtc_stop_alarm(struct max77686_rtc_info *info)
>> goto out;
>> }
>>
>> - max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
>> + max77686_rtc_data_to_tm(data, &tm, info);
>>
>> for (i = 0; i < RTC_NR_TIME; i++)
>> data[i] &= ~ALARM_ENABLE_MASK;
>> @@ -299,7 +311,7 @@ static int max77686_rtc_start_alarm(struct max77686_rtc_info *info)
>> goto out;
>> }
>>
>> - max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
>> + max77686_rtc_data_to_tm(data, &tm, info);
>>
>> data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
>> data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
>> @@ -307,7 +319,7 @@ static int max77686_rtc_start_alarm(struct max77686_rtc_info *info)
>> data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
>> if (data[RTC_MONTH] & 0xf)
>> data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
>> - if (data[RTC_YEAR] & 0x7f)
>> + if (data[RTC_YEAR] & info->drv_data->mask)
>> data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
>> if (data[RTC_DATE] & 0x1f)
>> data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);
>> @@ -436,6 +448,7 @@ static int max77686_rtc_probe(struct platform_device *pdev)
>> info->dev = &pdev->dev;
>> info->max77686 = max77686;
>> info->rtc = max77686->rtc;
>> + info->drv_data = (struct rtc_driver_data *)pdev->id_entry->driver_data;
>
> That cast dropping constness is bad.
>
Agreed, fixed.
> Best regards,
> Krzysztof
>
Best regards,
--
Javier Martinez Canillas
Open Source Group
Samsung Research America
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