Messages in this thread | | | Subject | Re: [EXT] Re: [v2] rtc: pcf85363/pcf85263: fix error that failed to run hwclock -w | From | Nandor Han <> | Date | Mon, 26 Aug 2019 12:17:11 +0300 |
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On 8/26/19 7:29 AM, Biwen Li wrote: >> >> On 8/16/19 10:40 PM, Li Yang wrote: >>> On Fri, Aug 16, 2019 at 11:30 AM Alexandre Belloni >>> <alexandre.belloni@bootlin.com> wrote: >>>> >>>> On 16/08/2019 10:50:49-0500, Li Yang wrote: >>>>> On Fri, Aug 16, 2019 at 3:05 AM Alexandre Belloni >>>>> <alexandre.belloni@bootlin.com> wrote: >>>>>> >>>>>> On 16/08/2019 10:46:36+0800, Biwen Li wrote: >>>>>>> Issue: >>>>>>> - # hwclock -w >>>>>>> hwclock: RTC_SET_TIME: Invalid argument >>>>>>> >>>>>>> Why: >>>>>>> - Relative patch: >> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.org >> %2Flkml%2F2019%2F4%2F3%2F55&data=02%7C01%7Cbiwen.li%40nxp. >> com%7Cff8cebc3f1034ae3fa9608d725ff9e5e%7C686ea1d3bc2b4c6fa92cd99 >> c5c301635%7C0%7C0%7C637019652111923736&sdata=spY6e22YOkOF >> 3%2BF7crSM0M6xPmOhgULDqMZLQw%2BAmdI%3D&reserved=0 , this >> patch >>>>>>> will always check for unwritable registers, it will compare reg >>>>>>> with max_register in regmap_writeable. >>>>>>> >>>>>>> - In drivers/rtc/rtc-pcf85363.c, CTRL_STOP_EN is 0x2e, but >> DT_100THS >>>>>>> is 0, max_regiter is 0x2f, then reg will be equal to 0x30, >>>>>>> '0x30 < 0x2f' is false,so regmap_writeable will return false. >>>>>>> >>>>>>> - Root cause: the buf[] was written to a wrong place in the file >>>>>>> drivers/rtc/rtc-pcf85363.c >>>>>>> >>>>>> >>>>>> This is not true, the RTC wraps the register accesses properly and >>>>>> this >>>>> >>>>> This performance hack probably deserve some explanation in the code >>>>> comment. :) >>>>> >>>>>> is probably something that should be handled by regmap_writable. >>>>> >>>>> The address wrapping is specific to this RTC chip. Is it also >>>>> commonly used by other I2C devices? I'm not sure if regmap_writable >>>>> should handle the wrapping case if it is too special. >>>>> >>>> >>>> Most of the i2c RTCs do address wrapping which is sometimes the only >>>> way to properly set the time. >>> >>> Adding Mark and Nandor to the loop. >>> >>> Regards, >>> Leo >>> >> >> Hi, >> `regmap` provides couple of ways to validate the registers: >> max_register, callback function and write table. All of these are optional, so it >> gives you the freedom to customize it as needed. >> >> In this situation probably you could: >> 1. Avoid using the wrapping feature of pcf85363 (you can just provide >> separate calls for stop, reset and time confguration). In this way the >> `max_register` validation method will work fine. > Yes, I use this way. Path as follows: > Stop and reset - > set time > stop >
Some of the concerns regarding this method was that it might not be precise enough. That because you need 2 I2C operations (one for stop and one for time configuration). Not sure about your case if this is a problem or not.
>> 2. Replace `max_register` method validation with `callback function` >> validation method, were you could make your own validation. > It is not work, show the code in as follows: > > bool regmap_writeable(struct regmap *map, unsigned int reg) > { > if (map->max_register && reg > map->max_register) > return false; > Callback function (writeable_reg) will not be called. > if (map->writeable_reg) > return map->writeable_reg(map->dev, reg);
Hi Li, If you *replace* the `max_register` method with `callback function` it should work. The code above will use every method *if provided*. In other words if `map->max_register` is 0 will go to the next step and check `map->writeable_reg`. Right?
Regards, Nandor
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