Messages in this thread Patch in this message | | | From | Biwen Li <> | Subject | [v4] rtc: pcf85363/pcf85263: fix error that failed to run hwclock -w | Date | Tue, 27 Aug 2019 12:37:35 +0800 |
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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 <biwen.li@nxp.com> --- 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
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