target/linux/xburst/patches-3.10/007-RTC-JZ4740-Init-the-regulator-register-on-startup.patch

   1 From aff616f4a33bd3a9ab1506fdbe97fcfe285cb7b0 Mon Sep 17 00:00:00 2001
   2 From: Paul Cercueil <paul@crapouillou.net>
   3 Date: Thu, 13 Sep 2012 00:09:20 +0200
   4 Subject: [PATCH 07/16] RTC: JZ4740: Init the "regulator" register on startup.
   5
   6 This register controls the accuracy of the RTC. uC/OS-II use
   7 the RTC as a 100Hz clock, and writes a completely wrong value
   8 on that register, that we have to overwrite if we want a working
   9 real-time clock.
  10
  11 Signed-off-by: Paul Cercueil <paul@crapouillou.net>
  12 Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
  13 ---
  14  drivers/rtc/rtc-jz4740.c |   17 +++++++++++++++++
  15  1 file changed, 17 insertions(+)
  16
  17 diff --git a/drivers/rtc/rtc-jz4740.c b/drivers/rtc/rtc-jz4740.c
  18 index 1e48686..722fb0c 100644
  19 --- a/drivers/rtc/rtc-jz4740.c
  20 +++ b/drivers/rtc/rtc-jz4740.c
  21 @@ -14,6 +14,7 @@
  22   *
  23   */
  24
  25 +#include <linux/clk.h>
  26  #include <linux/kernel.h>
  27  #include <linux/module.h>
  28  #include <linux/platform_device.h>
  29 @@ -215,6 +216,7 @@ static int jz4740_rtc_probe(struct platform_device *pdev)
  30         int ret;
  31         struct jz4740_rtc *rtc;
  32         uint32_t scratchpad;
  33 +       struct clk *rtc_clk;
  34
  35         rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
  36         if (!rtc)
  37 @@ -280,6 +282,21 @@ static int jz4740_rtc_probe(struct platform_device *pdev)
  38                 }
  39         }
  40
  41 +       rtc_clk = clk_get(&pdev->dev, "rtc");
  42 +       if (IS_ERR(rtc_clk)) {
  43 +               dev_err(&pdev->dev, "Failed to get RTC clock\n");
  44 +               goto err_free_irq;
  45 +       }
  46 +
  47 +       /* TODO: initialize the ADJC bits (25:16) to fine-tune
  48 +        * the accuracy of the RTC */
  49 +       ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_REGULATOR,
  50 +                               (clk_get_rate(rtc_clk) - 1) & 0xffff);
  51 +       clk_put(rtc_clk);
  52 +
  53 +       if (ret)
  54 +               dev_warn(&pdev->dev, "Could not update RTC regulator register\n");
  55 +
  56         return 0;
  57
  58  err_free_irq:
  59 --
  60 1.7.10.4
  61