From: Thomas Bogendoerfer Date: Thu, 10 Sep 2020 08:41:24 +0000 (+0200) Subject: rtc: ds1685: Fix bank switching to avoid endless loop X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9f8010e71f091b0609452742cfed4650ee633c44;p=linux.git rtc: ds1685: Fix bank switching to avoid endless loop ds1685_rtc_begin_data_access() tried to access an extended register before enabling access to it by switching to bank 1. Depending on content in NVRAM this could lead to an endless loop. While at it fix also switch back to bank 0 in ds1685_rtc_end_data_access(). Signed-off-by: Thomas Bogendoerfer Signed-off-by: Alexandre Belloni Acked-by: Joshua Kinard Link: https://lore.kernel.org/r/20200910084124.138560-1-tsbogend@alpha.franken.de --- diff --git a/drivers/rtc/rtc-ds1685.c b/drivers/rtc/rtc-ds1685.c index 56c670af2e50d..dfbd7b88b2b91 100644 --- a/drivers/rtc/rtc-ds1685.c +++ b/drivers/rtc/rtc-ds1685.c @@ -193,12 +193,12 @@ ds1685_rtc_begin_data_access(struct ds1685_priv *rtc) rtc->write(rtc, RTC_CTRL_B, (rtc->read(rtc, RTC_CTRL_B) | RTC_CTRL_B_SET)); + /* Switch to Bank 1 */ + ds1685_rtc_switch_to_bank1(rtc); + /* Read Ext Ctrl 4A and check the INCR bit to avoid a lockout. */ while (rtc->read(rtc, RTC_EXT_CTRL_4A) & RTC_CTRL_4A_INCR) cpu_relax(); - - /* Switch to Bank 1 */ - ds1685_rtc_switch_to_bank1(rtc); } /** @@ -213,7 +213,7 @@ static inline void ds1685_rtc_end_data_access(struct ds1685_priv *rtc) { /* Switch back to Bank 0 */ - ds1685_rtc_switch_to_bank1(rtc); + ds1685_rtc_switch_to_bank0(rtc); /* Clear the SET bit in Ctrl B */ rtc->write(rtc, RTC_CTRL_B,