On Mon, Mar 04, 2013 at 03:05:43PM +0100, Steffen Trumtrar wrote:
> From: Juergen Beisert <[email protected]>
>
> Reflect the possibilities via device tree and configure the RTC correctly
>
> Signed-off-by: Juergen Beisert <[email protected]>
> Signed-off-by: Steffen Trumtrar <[email protected]>
> ---
> arch/arm/boot/dts/imx28.dtsi | 2 ++
> drivers/rtc/rtc-stmp3xxx.c | 76
> ++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 78 insertions(+)
>
> diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
> index dcd0844..d89af79 100644
> --- a/arch/arm/boot/dts/imx28.dtsi
> +++ b/arch/arm/boot/dts/imx28.dtsi
> @@ -818,6 +818,8 @@
> compatible = "fsl,imx28-rtc",
> "fsl,stmp3xxx-rtc";
> reg = <0x80056000 0x2000>;
> interrupts = <29>;
> + clocks = <&clks 65>, <&clks 40> ;
> + clock-names = "32k", "24m";
The changes should be in some mxs/arch patch.
> };
>
> i2c0: i2c@80058000 {
> diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
> index 7311292..fb4b823 100644
> --- a/drivers/rtc/rtc-stmp3xxx.c
> +++ b/drivers/rtc/rtc-stmp3xxx.c
> @@ -21,6 +21,7 @@
> #include <linux/module.h>
> #include <linux/io.h>
> #include <linux/init.h>
> +#include <linux/clk.h>
> #include <linux/platform_device.h>
> #include <linux/interrupt.h>
> #include <linux/rtc.h>
> @@ -176,11 +177,55 @@ static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void
> *dev_id)
> return IRQ_NONE;
> }
>
> +/*
> + * To keep the energy consumption low, keep only
> + * the really used oscillator running when the power is down
> + */
> +static void stmp3xxx_alarm_keep_oscillator(const struct stmp3xxx_rtc_data
> *rtc_data)
> +{
> + switch (rtc_data->clk_src) {
> + case MXS_OSC_24M:
> + /* keep the 24 MHz oscillator running even in power down */
> + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ | /* 24 MHz / 750 */
> + STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP,
> + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
> + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
> + STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE,
> + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
> + break;
> + case MXS_OSC_32K:
> + /* keep the 32 kHz oscillator running even in power down */
> + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ | /* 32 kHz */
> + STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
> + STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE,
> + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
> + writel(STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP,
> + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
> + break;
> + case MXS_OSC_32K768:
> + /* keep the 32 kHz oscillator running even in power down */
> + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
> + STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE,
> + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
> + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ | /* 32.768 kHz */
> + STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP,
> + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
> + break;
> + case MXS_UNKNOWN:
> + default:
> + break;
> + }
> +}
> +
> static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int
> enabled)
> {
> struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
>
> + stmp3xxx_alarm_keep_oscillator(rtc_data);
> +
> if (enabled) {
> + writel(STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE, /* to be able to
> sleep */
> + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
> writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
> STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
> rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
> @@ -248,6 +293,8 @@ static int stmp3xxx_rtc_probe(struct platform_device
> *pdev)
> {
> struct stmp3xxx_rtc_data *rtc_data;
> struct resource *r;
> + struct clk *clk;
> + unsigned long rate;
> int err;
>
> rtc_data = kzalloc(sizeof *rtc_data, GFP_KERNEL);
> @@ -280,6 +327,35 @@ static int stmp3xxx_rtc_probe(struct platform_device
> *pdev)
> platform_set_drvdata(pdev, rtc_data);
>
> mxs_reset_block(rtc_data->io);
> +
> + /*
> + * configure the RTC to provide the correct time
> + */
> + clk = clk_get(&pdev->dev, "32k");
devm_clk_get
Shawn
> + if (IS_ERR(clk)) {
> + /* just a fall back */
> + dev_warn(&pdev->dev, "RTC's input clock undefined\n");
> + rtc_data->clk_src = MXS_OSC_24M;
> + } else {
> + rate = clk_get_rate(clk);
> + if (rate == 0) {
> + /* no dedicated external crystal */
> + rtc_data->clk_src = MXS_OSC_24M;
> + dev_info(&pdev->dev, "Using 24 MHz as RTC's clock\n");
> + } else if (rate == 32000) {
> + rtc_data->clk_src = MXS_OSC_32K;
> + dev_info(&pdev->dev, "Using 32.0 kHz as RTC's clock\n");
> + } else if (rate == 32768) {
> + rtc_data->clk_src = MXS_OSC_32K768;
> + dev_info(&pdev->dev, "Using 32.768 kHz as RTC's
> clock\n");
> + } else
> + dev_warn(&pdev->dev,
> + "Cannot init the RTC's clock source\n");
> + }
> +
> + /* basically configure the RTC's input clock */
> + stmp3xxx_alarm_keep_oscillator(rtc_data);
> +
> writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
> STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
> STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
> --
> 1.7.10.4
>
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