From f05b1ecd7e4fde7e69320a4b7be461636e982991 Mon Sep 17 00:00:00 2001 From: Paul Cercueil Date: Thu, 13 Sep 2012 00:09:20 +0200 Subject: [PATCH 5/7] RTC: JZ4740: Init the "regulator" register on startup. This register controls the accuracy of the RTC. uC/OS-II use the RTC as a 100Hz clock, and writes a completely wrong value on that register, that we have to overwrite if we want a working real-time clock. Signed-off-by: Paul Cercueil --- drivers/rtc/rtc-jz4740.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) --- a/drivers/rtc/rtc-jz4740.c +++ b/drivers/rtc/rtc-jz4740.c @@ -15,6 +15,7 @@ */ #include +#include #include #include #include @@ -216,6 +217,7 @@ static int jz4740_rtc_probe(struct platf struct jz4740_rtc *rtc; uint32_t scratchpad; struct resource *mem; + struct clk *rtc_clk; rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); if (!rtc) @@ -263,6 +265,21 @@ static int jz4740_rtc_probe(struct platf } } + rtc_clk = clk_get(&pdev->dev, "rtc"); + if (IS_ERR(rtc_clk)) { + dev_err(&pdev->dev, "Failed to get RTC clock\n"); + return PTR_ERR(rtc_clk); + } + + /* TODO: initialize the ADJC bits (25:16) to fine-tune + * the accuracy of the RTC */ + ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_REGULATOR, + (clk_get_rate(rtc_clk) - 1) & 0xffff); + clk_put(rtc_clk); + + if (ret) + dev_warn(&pdev->dev, "Could not update RTC regulator register\n"); + return 0; }