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 --- a/drivers/rtc/rtc-jz4740.c
  18 +++ b/drivers/rtc/rtc-jz4740.c
  19 @@ -14,6 +14,7 @@
  20   *
  21   */
  22
  23 +#include <linux/clk.h>
  24  #include <linux/kernel.h>
  25  #include <linux/module.h>
  26  #include <linux/platform_device.h>
  27 @@ -215,6 +216,7 @@ static int jz4740_rtc_probe(struct platf
  28         int ret;
  29         struct jz4740_rtc *rtc;
  30         uint32_t scratchpad;
  31 +       struct clk *rtc_clk;
  32
  33         rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
  34         if (!rtc)
  35 @@ -280,6 +282,21 @@ static int jz4740_rtc_probe(struct platf
  36                 }
  37         }
  38
  39 +       rtc_clk = clk_get(&pdev->dev, "rtc");
  40 +       if (IS_ERR(rtc_clk)) {
  41 +               dev_err(&pdev->dev, "Failed to get RTC clock\n");
  42 +               goto err_free_irq;
  43 +       }
  44 +
  45 +       /* TODO: initialize the ADJC bits (25:16) to fine-tune
  46 +        * the accuracy of the RTC */
  47 +       ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_REGULATOR,
  48 +                               (clk_get_rate(rtc_clk) - 1) & 0xffff);
  49 +       clk_put(rtc_clk);
  50 +
  51 +       if (ret)
  52 +               dev_warn(&pdev->dev, "Could not update RTC regulator register\n");
  53 +
  54         return 0;
  55
  56  err_free_irq: