git.openwrt.org Git - openwrt/staging/blocktrron.git/blob

   1 From 39869587dac09c9e738960ccdf01e1dc62a906f7 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Mon, 29 Oct 2018 14:45:45 +0000
   4 Subject: [PATCH] Revert "rtc: pcf8523: properly handle oscillator stop
   5  bit"
   6
   7 This reverts commit ede44c908d44b166a5b6bd7caacd105c2ff5a70f.
   8
   9 See: https://github.com/raspberrypi/firmware/issues/1065
  10
  11 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
  12 ---
  13  drivers/rtc/rtc-pcf8523.c | 24 ++++++++++++++++++++++--
  14  1 file changed, 22 insertions(+), 2 deletions(-)
  15
  16 --- a/drivers/rtc/rtc-pcf8523.c
  17 +++ b/drivers/rtc/rtc-pcf8523.c
  18 @@ -242,8 +242,28 @@ static int pcf8523_rtc_read_time(struct
  19         if (err < 0)
  20                 return err;
  21
  22 -       if (regs[0] & PCF8523_SECONDS_OS)
  23 -               return -EINVAL;
  24 +       if (regs[0] & PCF8523_SECONDS_OS) {
  25 +               /*
  26 +                * If the oscillator was stopped, try to clear the flag. Upon
  27 +                * power-up the flag is always set, but if we cannot clear it
  28 +                * the oscillator isn't running properly for some reason. The
  29 +                * sensible thing therefore is to return an error, signalling
  30 +                * that the clock cannot be assumed to be correct.
  31 +                */
  32 +
  33 +               regs[0] &= ~PCF8523_SECONDS_OS;
  34 +
  35 +               err = pcf8523_write(client, PCF8523_REG_SECONDS, regs[0]);
  36 +               if (err < 0)
  37 +                       return err;
  38 +
  39 +               err = pcf8523_read(client, PCF8523_REG_SECONDS, &regs[0]);
  40 +               if (err < 0)
  41 +                       return err;
  42 +
  43 +               if (regs[0] & PCF8523_SECONDS_OS)
  44 +                       return -EAGAIN;
  45 +       }
  46
  47         tm->tm_sec = bcd2bin(regs[0] & 0x7f);
  48         tm->tm_min = bcd2bin(regs[1] & 0x7f);