RE: [EXT] Re: [v4] rtc: pcf85363/pcf85263: fix error that failed to run hwclock -w
> > On 8/27/19 7:37 AM, Biwen Li wrote: > > - 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. > > > > - The pcf85363/pcf85263 has the capability of address wrapping > >which means if you access a continuous address range across a > >certain boundary(max_register of struct regmap_config) the > >hardware actually wraps the access to a lower address. But the > >address violation check of regmap rejects such access. > > nitpick: This 2 paragraphs could be combined to clear up the issue: > > ` > The pcf85363/pcf85263 has the capability of address wrapping which means if > you access an address outside the allowed range > (0x00-0x2f) the hardware actually wraps the access to a lower address. > The rtc-pf85363 driver will use this feature to configure the time and > execute 2 > actions in the same i2c write operation (stopping the clock and configure the > time). However the driver has also configured the `regmap maxregister` > protection mechanism that will block accessing addresses outside valid range > (0x00-0x2f). > ` > > nitpick: I would also use separate buffers for this actions. Up to you :) > > Otherwise LGTM +1 Thanks, it's a beautiful explanation. > > Nandor
Re: [v4] rtc: pcf85363/pcf85263: fix error that failed to run hwclock -w
On 8/27/19 7:37 AM, Biwen Li wrote: - 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. - The pcf85363/pcf85263 has the capability of address wrapping which means if you access a continuous address range across a certain boundary(max_register of struct regmap_config) the hardware actually wraps the access to a lower address. But the address violation check of regmap rejects such access. nitpick: This 2 paragraphs could be combined to clear up the issue: ` The pcf85363/pcf85263 has the capability of address wrapping which means if you access an address outside the allowed range (0x00-0x2f) the hardware actually wraps the access to a lower address. The rtc-pf85363 driver will use this feature to configure the time and execute 2 actions in the same i2c write operation (stopping the clock and configure the time). However the driver has also configured the `regmap maxregister` protection mechanism that will block accessing addresses outside valid range (0x00-0x2f). ` nitpick: I would also use separate buffers for this actions. Up to you :) Otherwise LGTM +1 Nandor
[v4] rtc: pcf85363/pcf85263: fix error that failed to run hwclock -w
Issue: - # hwclock -w hwclock: RTC_SET_TIME: Invalid argument Why: - Relative commit: 8b9f9d4dc511309918c4f6793bae7387c0c638af, 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. - The pcf85363/pcf85263 has the capability of address wrapping which means if you access a continuous address range across a certain boundary(max_register of struct regmap_config) the hardware actually wraps the access to a lower address. But the address violation check of regmap rejects such access. How: - Split of writing regs to two parts, first part writes control registers about stop_enable and resets, second part writes RTC time and date registers. Signed-off-by: Biwen Li --- Change in v4: - use old scheme - replace link to lkml.org with commit - add proper explanation Change in v3: - replace old scheme with new scheme: increase max_register. Change in v2: - add Why and How into commit message. drivers/rtc/rtc-pcf85363.c | 7 ++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/rtc/rtc-pcf85363.c b/drivers/rtc/rtc-pcf85363.c index a075e77617dc..3450d615974d 100644 --- a/drivers/rtc/rtc-pcf85363.c +++ b/drivers/rtc/rtc-pcf85363.c @@ -166,7 +166,12 @@ static int pcf85363_rtc_set_time(struct device *dev, struct rtc_time *tm) buf[DT_YEARS] = bin2bcd(tm->tm_year % 100); ret = regmap_bulk_write(pcf85363->regmap, CTRL_STOP_EN, - tmp, sizeof(tmp)); + tmp, 2); + if (ret) + return ret; + + ret = regmap_bulk_write(pcf85363->regmap, DT_100THS, + buf, sizeof(tmp) - 2); if (ret) return ret; -- 2.17.1
