From: Biwen Li biwen.li@nxp.com
[ Upstream commit 7ef66122bdb3b839e9f51b76d7e600b6e21ef648 ]
Issue: - # hwclock -w hwclock: RTC_SET_TIME: Invalid argument
Why: - Relative commit: 8b9f9d4dc511 ("regmap: verify if register is writeable before writing operations"), this patch will always check for unwritable registers, it will compare reg with max_register in regmap_writeable.
- The pcf85363/pcf85263 has the capability of address wrapping which means if you access an address outside the allowed range (0x00-0x2f) hardware actually wraps the access to a lower address. The rtc-pcf85363 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).
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 Link: https://lore.kernel.org/r/20190829021418.4607-1-biwen.li@nxp.com Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 a075e77617dcb..3450d615974d5 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;