[PATCH v2 0/9] rtc: stmp3xxx: DT bindings and wakealarm

[PATCH v2 0/9] rtc: stmp3xxx: DT bindings and wakealarm

[Steffen Trumtrar]

Hi!

Changes since v1:
	- renamed patches
	- reworked commit messages
	- squashed patches
	- added missing SOB
	- match on rtc nodename instead of using a new binding
	- general cleanup

I did not rework the sysfs stuff, as I'm still not sure if this
is wrong for bin_attributes or not.

Based on v3.9-rc1

Regards,
Steffen


Juergen Beisert (2):
  ARM: i.MX28: define osc in DT
  ARM: i.MX28: define external RTC crystal in DT

Steffen Trumtrar (7):
  ARM: i.MX28: dts: add clocks for stmp3xxx RTC
  rtc: stmp3xxx: allow different oscillators
  rtc: stmp3xxx: enable wakeup functionality
  rtc: stmp3xxx: add sysfs entries for persistent regs
  rtc: stmp3xxx: Re-enable active alarm
  rtc: stmp3xxx: Check copy controller state
  rtc: stmp3xxx: Replace wait_time function

 .../devicetree/bindings/clock/imx28-clock.txt      |   1 +
 arch/arm/boot/dts/imx28.dtsi                       |  19 ++
 drivers/clk/mxs/clk-imx28.c                        |  20 +-
 drivers/rtc/rtc-stmp3xxx.c                         | 282 +++++++++++++++++++--
 4 files changed, 305 insertions(+), 17 deletions(-)

-- 
1.8.2.rc2

[PATCH v2 1/9] ARM: i.MX28: define osc in DT

[Steffen Trumtrar]

From: Juergen Beisert <jbe-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

Instead of hardcoding the ref_xtal in the clk driver, get it from the DT.

Signed-off-by: Juergen Beisert <jbe-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 arch/arm/boot/dts/imx28.dtsi | 11 +++++++++++
 drivers/clk/mxs/clk-imx28.c  | 16 +++++++++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
index 7ba4966..b9e3712 100644
--- a/arch/arm/boot/dts/imx28.dtsi
+++ b/arch/arm/boot/dts/imx28.dtsi
@@ -37,6 +37,17 @@
 		};
 	};
 
+	clocks {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		osc24m: system-oscillator {
+			compatible = "fixed-clock";
+			#clock-cells = <0>;
+			clock-frequency = <24000000>;
+		};
+	};
+
 	apb@80000000 {
 		compatible = "simple-bus";
 		#address-cells = <1>;
diff --git a/drivers/clk/mxs/clk-imx28.c b/drivers/clk/mxs/clk-imx28.c
index 76ce6c6..01048b5 100644
--- a/drivers/clk/mxs/clk-imx28.c
+++ b/drivers/clk/mxs/clk-imx28.c
@@ -158,7 +158,21 @@ int __init mx28_clocks_init(void)
 
 	clk_misc_init();
 
-	clks[ref_xtal] = mxs_clk_fixed("ref_xtal", 24000000);
+	/* retrieve the crystal's frequencies from device tree */
+	for_each_compatible_node(np, NULL, "fixed-clock") {
+		u32 rate;
+
+		if (of_property_read_u32(np, "clock-frequency", &rate))
+			continue;
+
+		if (of_device_is_compatible(np, "fsl,mxs-system"))
+			clks[ref_xtal] = mxs_clk_fixed("ref_xtal", rate);
+	}
+
+	/* if not set, guess their frequency */
+	if (clks[ref_xtal] == NULL)
+		clks[ref_xtal] = mxs_clk_fixed("ref_xtal", 24000000);
+
 	clks[pll0] = mxs_clk_pll("pll0", "ref_xtal", PLL0CTRL0, 17, 480000000);
 	clks[pll1] = mxs_clk_pll("pll1", "ref_xtal", PLL1CTRL0, 17, 480000000);
 	clks[pll2] = mxs_clk_pll("pll2", "ref_xtal", PLL2CTRL0, 23, 50000000);
-- 
1.8.2.rc2

Re: [PATCH v2 1/9] ARM: i.MX28: define osc in DT

[Shawn Guo]

On Fri, Mar 08, 2013 at 10:01:36AM +0100, Steffen Trumtrar wrote:
> From: Juergen Beisert <jbe-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> 
> Instead of hardcoding the ref_xtal in the clk driver, get it from the DT.
> 
> Signed-off-by: Juergen Beisert <jbe-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
>  arch/arm/boot/dts/imx28.dtsi | 11 +++++++++++
>  drivers/clk/mxs/clk-imx28.c  | 16 +++++++++++++++-
>  2 files changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
> index 7ba4966..b9e3712 100644
> --- a/arch/arm/boot/dts/imx28.dtsi
> +++ b/arch/arm/boot/dts/imx28.dtsi
> @@ -37,6 +37,17 @@
>  		};
>  	};
>  
> +	clocks {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +
> +		osc24m: system-oscillator {
> +			compatible = "fixed-clock";
> +			#clock-cells = <0>;
> +			clock-frequency = <24000000>;
> +		};
> +	};
> +
>  	apb@80000000 {
>  		compatible = "simple-bus";
>  		#address-cells = <1>;
> diff --git a/drivers/clk/mxs/clk-imx28.c b/drivers/clk/mxs/clk-imx28.c
> index 76ce6c6..01048b5 100644
> --- a/drivers/clk/mxs/clk-imx28.c
> +++ b/drivers/clk/mxs/clk-imx28.c
> @@ -158,7 +158,21 @@ int __init mx28_clocks_init(void)
>  
>  	clk_misc_init();
>  
> -	clks[ref_xtal] = mxs_clk_fixed("ref_xtal", 24000000);
> +	/* retrieve the crystal's frequencies from device tree */
> +	for_each_compatible_node(np, NULL, "fixed-clock") {
> +		u32 rate;
> +
> +		if (of_property_read_u32(np, "clock-frequency", &rate))
> +			continue;
> +
> +		if (of_device_is_compatible(np, "fsl,mxs-system"))

Use node name to save the custom compatible.

But more fundamental question - do you really have a imx28 system
running a ref_xtal that is not 24 MHz?  Or does imx28 actually support
any other frequency ref_xtal other than 24 MHz?

Shawn

> +			clks[ref_xtal] = mxs_clk_fixed("ref_xtal", rate);
> +	}
> +
> +	/* if not set, guess their frequency */
> +	if (clks[ref_xtal] == NULL)
> +		clks[ref_xtal] = mxs_clk_fixed("ref_xtal", 24000000);
> +
>  	clks[pll0] = mxs_clk_pll("pll0", "ref_xtal", PLL0CTRL0, 17, 480000000);
>  	clks[pll1] = mxs_clk_pll("pll1", "ref_xtal", PLL1CTRL0, 17, 480000000);
>  	clks[pll2] = mxs_clk_pll("pll2", "ref_xtal", PLL2CTRL0, 23, 50000000);
> -- 
> 1.8.2.rc2
> 

[PATCH v2 2/9] ARM: i.MX28: define external RTC crystal in DT

[Steffen Trumtrar]

From: Juergen Beisert <jbe-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>

The RTC in the i.MX28 may be clocked with different crystals.
Get the rate of the connected one from the DT.

Signed-off-by: Juergen Beisert <jbe-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 Documentation/devicetree/bindings/clock/imx28-clock.txt | 1 +
 arch/arm/boot/dts/imx28.dtsi                            | 6 ++++++
 drivers/clk/mxs/clk-imx28.c                             | 4 +++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/clock/imx28-clock.txt b/Documentation/devicetree/bindings/clock/imx28-clock.txt
index e6587af..c3a9d94 100644
--- a/Documentation/devicetree/bindings/clock/imx28-clock.txt
+++ b/Documentation/devicetree/bindings/clock/imx28-clock.txt
@@ -76,6 +76,7 @@ clocks and IDs.
 	usb0_phy	62
 	usb1_phy	63
 	enet_out	64
+	rtc_32k		65
 
 Examples:
 
diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
index b9e3712..0393d3f 100644
--- a/arch/arm/boot/dts/imx28.dtsi
+++ b/arch/arm/boot/dts/imx28.dtsi
@@ -46,6 +46,12 @@
 			#clock-cells = <0>;
 			clock-frequency = <24000000>;
 		};
+
+		osc32k: rtc-oscillator {
+			compatible = "fixed-clock";
+			#clock-cells = <0>;
+			clock-frequency = <0>;
+		};
 	};
 
 	apb@80000000 {
diff --git a/drivers/clk/mxs/clk-imx28.c b/drivers/clk/mxs/clk-imx28.c
index 01048b5..acf2762 100644
--- a/drivers/clk/mxs/clk-imx28.c
+++ b/drivers/clk/mxs/clk-imx28.c
@@ -141,7 +141,7 @@ enum imx28_clk {
 	clk32k_div, rtc, lradc, spdif_div, clk32k, pwm, uart, ssp0,
 	ssp1, ssp2, ssp3, gpmi, spdif, emi, saif0, saif1, lcdif, etm,
 	fec, can0, can1, usb0, usb1, usb0_phy, usb1_phy, enet_out,
-	clk_max
+	rtc_32k, clk_max
 };
 
 static struct clk *clks[clk_max];
@@ -167,6 +167,8 @@ int __init mx28_clocks_init(void)
 
 		if (of_device_is_compatible(np, "fsl,mxs-system"))
 			clks[ref_xtal] = mxs_clk_fixed("ref_xtal", rate);
+		else if (!strncmp(np->name, "rtc-oscillator", strlen("rtc-oscillator")))
+			clks[rtc_32k] = mxs_clk_fixed("rtc32k", rate);
 	}
 
 	/* if not set, guess their frequency */
-- 
1.8.2.rc2

[PATCH v2 3/9] ARM: i.MX28: dts: add clocks for stmp3xxx RTC

[Steffen Trumtrar]

The stmp3xxx can handle multiple clocks. Add them to the DT.

Signed-off-by: Juergen Beisert <jbe-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 arch/arm/boot/dts/imx28.dtsi | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
index 0393d3f..469a23f 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";
 			};
 
 			i2c0: i2c@80058000 {
-- 
1.8.2.rc2

[PATCH v2 4/9] rtc: stmp3xxx: allow different oscillators

[Steffen Trumtrar]

The RTC can have different input clockrates.
Configure the RTC accordingly and leave only the one used running.

Signed-off-by: Juergen Beisert <jbe-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/rtc/rtc-stmp3xxx.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)

diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index 98f0d3c..d2283c5 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>
@@ -53,18 +54,31 @@
 #define STMP3XXX_RTC_PERSISTENT0		0x60
 #define STMP3XXX_RTC_PERSISTENT0_SET		0x64
 #define STMP3XXX_RTC_PERSISTENT0_CLR		0x68
+#define STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE	(1 << 0)
 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN	0x00000002
 #define STMP3XXX_RTC_PERSISTENT0_ALARM_EN	0x00000004
+#define STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP (1 << 4)
+#define STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP (1 << 5)
+#define STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ	(1 << 6)
+
 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE	0x00000080
 
 #define STMP3XXX_RTC_PERSISTENT1		0x70
 /* missing bitmask in headers */
 #define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER	0x80000000
 
+enum clock_source {
+	MXS_UNKNOWN,
+	MXS_OSC_24M,
+	MXS_OSC_32K,
+	MXS_OSC_32K768
+};
+
 struct stmp3xxx_rtc_data {
 	struct rtc_device *rtc;
 	void __iomem *io;
 	int irq_alarm;
+	enum clock_source clk_src;
 };
 
 #if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG)
@@ -168,11 +182,55 @@ 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);
@@ -240,6 +298,8 @@ 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);
@@ -272,6 +332,35 @@ 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 = devm_clk_get(&pdev->dev, "32k");
+	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,
-- 
1.8.2.rc2

[PATCH v2 5/9] rtc: stmp3xxx: enable wakeup functionality

[Steffen Trumtrar]

This RTC can wakeup the system. Register the device accordingly.

Signed-off-by: Juergen Beisert <jbe-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/rtc/rtc-stmp3xxx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index d2283c5..cd844ec 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -370,6 +370,9 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev)
 			STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 			rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 
+	/* this RTC can wake up the system */
+	device_init_wakeup(&pdev->dev, true);
+
 	rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev,
 				&stmp3xxx_rtc_ops, THIS_MODULE);
 	if (IS_ERR(rtc_data->rtc)) {
-- 
1.8.2.rc2

[PATCH v2 6/9] rtc: stmp3xxx: add sysfs entries for persistent regs

[Steffen Trumtrar]

The persistent registers 1-5 are completely software defined. To have access
from userspace, export them via sysfs.

Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/rtc/rtc-stmp3xxx.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index cd844ec..3ca26ac 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -67,6 +67,8 @@
 /* missing bitmask in headers */
 #define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER	0x80000000
 
+#define STMP3XXX_RTC_PERSISTENT_LEN            (0xC0 - STMP3XXX_RTC_PERSISTENT1)
+
 enum clock_source {
 	MXS_UNKNOWN,
 	MXS_OSC_24M,
@@ -79,6 +81,9 @@ struct stmp3xxx_rtc_data {
 	void __iomem *io;
 	int irq_alarm;
 	enum clock_source clk_src;
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+	struct bin_attribute *persist;
+#endif
 };
 
 #if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG)
@@ -267,6 +272,42 @@ static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+static ssize_t stmp3xxx_rtc_persist_read(struct file *filep,
+					 struct kobject *kobj,
+					 struct bin_attribute *bin_attr,
+					 char *buf, loff_t off, size_t size)
+{
+	struct rtc_device *rtc = container_of(kobj, struct rtc_device,
+					      dev.kobj);
+	struct device *dev = rtc->dev.parent;
+	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
+	ssize_t count;
+
+	for (count = 0; size; size--, off++, count++)
+		*buf++ = readl(rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + off);
+
+	return count;
+}
+
+static ssize_t stmp3xxx_rtc_persist_write(struct file *filep,
+					  struct kobject *kobj,
+					  struct bin_attribute *bin_attr,
+					  char *buf, loff_t off, size_t size)
+{
+	struct rtc_device *rtc = container_of(kobj, struct rtc_device,
+					      dev.kobj);
+	struct device *dev = rtc->dev.parent;
+	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
+	ssize_t count;
+
+	for (count = 0; size; size--, off++, count++)
+		writel(*buf++, rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + off);
+
+	return count;
+}
+#endif
+
 static struct rtc_class_ops stmp3xxx_rtc_ops = {
 	.alarm_irq_enable =
 			  stmp3xxx_alarm_irq_enable,
@@ -283,6 +324,11 @@ static int stmp3xxx_rtc_remove(struct platform_device *pdev)
 	if (!rtc_data)
 		return 0;
 
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+	sysfs_remove_bin_file(&pdev->dev.kobj, rtc_data->persist);
+	kfree(rtc_data->persist);
+#endif
+
 	writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 			rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 	free_irq(rtc_data->irq_alarm, &pdev->dev);
@@ -389,8 +435,31 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev)
 	}
 
 	stmp3xxx_wdt_register(pdev);
+
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+	rtc_data->persist = kzalloc(sizeof(struct bin_attribute), GFP_KERNEL);
+	if (!rtc_data->persist) {
+		err = -ENOMEM;
+		goto out_persist;
+	}
+
+	rtc_data->persist->attr.name = "persistent";
+	rtc_data->persist->attr.mode = S_IRUGO | S_IWUSR;
+	sysfs_bin_attr_init(rtc_data->persist);
+	rtc_data->persist->read = stmp3xxx_rtc_persist_read;
+	rtc_data->persist->write = stmp3xxx_rtc_persist_write;
+	rtc_data->persist->size = STMP3XXX_RTC_PERSISTENT_LEN;
+	err = sysfs_create_bin_file(&rtc_data->rtc->dev.kobj,
+				rtc_data->persist);
+	if (err) {
+		kfree(rtc_data->persist);
+		goto out_persist;
+	}
+#endif
+
 	return 0;
 
+out_persist:
 out_irq_alarm:
 	rtc_device_unregister(rtc_data->rtc);
 out_remap:
-- 
1.8.2.rc2

[PATCH v2 7/9] rtc: stmp3xxx: Re-enable active alarm

[Steffen Trumtrar]

If an alarm is set and the system rebooted, the alarm does not get re-enabled,
although it may still be valid (i.e. in the future).

The sysfs representation of wakealarms prevents overwriting active alarms. One
needs to instead write a 0 first and then the new value. Therefore an alarm is
considered active if
	wakealarm != 0 && wakealarm > now

To preserve this information over a reboot, the alarm needs to be re-written
on startup, if it is still valid. This leads to all flags being reactivated
and interrupts reenabled.

Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/rtc/rtc-stmp3xxx.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index 3ca26ac..90d0804 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -247,27 +247,39 @@ static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 				rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 		writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 				rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
+		writel(0, rtc_data->io + STMP3XXX_RTC_ALARM);
 	}
 	return 0;
 }
 
-static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
+	unsigned long t;
 	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 
-	rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time);
+	rtc_tm_to_time(&alm->time, &t);
+	writel(t, rtc_data->io + STMP3XXX_RTC_ALARM);
+
+	stmp3xxx_alarm_irq_enable(dev, alm->enabled);
+
 	return 0;
 }
 
-static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
-	unsigned long t;
 	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
+	struct rtc_time now;
+	u32 alarm = readl(rtc_data->io + STMP3XXX_RTC_ALARM);
 
-	rtc_tm_to_time(&alm->time, &t);
-	writel(t, rtc_data->io + STMP3XXX_RTC_ALARM);
+	rtc_time_to_tm(alarm, &alm->time);
 
-	stmp3xxx_alarm_irq_enable(dev, alm->enabled);
+	stmp3xxx_rtc_gettime(dev, &now);
+	if (rtc_tm_to_ktime(now).tv64 < rtc_tm_to_ktime(alm->time).tv64) {
+		alm->enabled = 1;
+		stmp3xxx_rtc_set_alarm(dev, alm);
+	} else {
+		alm->enabled = 0;
+	}
 
 	return 0;
 }
-- 
1.8.2.rc2

[PATCH v2 8/9] rtc: stmp3xxx: Check copy controller state

[Steffen Trumtrar]

The stmp3xxx has a copy controller that needs some time to copy the
analog side to the digital shadow registers. This has implications for
a correct reset behaviour.

The datasheet states that one should not reset the rtc if NEW_REGS != 0 or
a possible loss of data is to be expected.
Accordingly, one should not access the registers while STALE_REGS != 0.

If an alarm is written to the shadow registers, the copy controller does not
persist the values to the analog in every case. This is no problem in the
running kernel, but leads to lost values in case of a reboot.
Always check if the rtc is in a clean state, before writing or continueing.

Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/rtc/rtc-stmp3xxx.c | 91 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 90 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index 90d0804..3de868d 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -43,8 +43,18 @@
 
 #define STMP3XXX_RTC_STAT			0x10
 #define STMP3XXX_RTC_STAT_STALE_SHIFT		16
+#define STMP3XXX_RTC_STAT_NEW_SHIFT		8
 #define STMP3XXX_RTC_STAT_RTC_PRESENT		0x80000000
 
+#define STMP3XXX_RTC_STAT_PERS0_MASK		(1 << 0)
+#define STMP3XXX_RTC_STAT_PERS1_MASK		(1 << 1)
+#define STMP3XXX_RTC_STAT_PERS2_MASK		(1 << 2)
+#define STMP3XXX_RTC_STAT_PERS3_MASK		(1 << 3)
+#define STMP3XXX_RTC_STAT_PERS4_MASK		(1 << 4)
+#define STMP3XXX_RTC_STAT_PERS5_MASK		(1 << 5)
+#define STMP3XXX_RTC_STAT_ALARM_MASK		(1 << 6)
+#define STMP3XXX_RTC_STAT_SEC_MASK		(1 << 7)
+
 #define STMP3XXX_RTC_SECONDS			0x30
 
 #define STMP3XXX_RTC_ALARM			0x40
@@ -140,6 +150,35 @@ static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
 }
 #endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */
 
+static inline void stmp3xxx_wait_copy_ctrl(const struct stmp3xxx_rtc_data *rtc_data,
+					   const unsigned int shift,
+					   unsigned int mask)
+{
+	/*
+	 * totally random number, as the datasheet is very unclear
+	 * about the timings
+	 */
+	int timeout = 0x8000;
+
+	while ((readl(rtc_data->io + STMP3XXX_RTC_STAT) &
+			(mask << shift)) && --timeout)
+		cpu_relax();
+
+	if (unlikely(!timeout)) {
+		if (&rtc_data->rtc->dev) {
+			dev_warn(&rtc_data->rtc->dev,
+				"possible data loss of shadow registers\n");
+		} else {
+			/*
+			 * When this function is called for the mxs_reset in
+			 * the probe function, rtc->dev is not yet set
+			 * FIXME: find a better/correct way to do this
+			 */
+			pr_warn("possible data loss of rtc shadow registers\n");
+		}
+	}
+}
+
 static void stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
 {
 	/*
@@ -193,6 +232,9 @@ static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id)
  */
 static void stmp3xxx_alarm_keep_oscillator(const struct stmp3xxx_rtc_data *rtc_data)
 {
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_STALE_SHIFT,
+				STMP3XXX_RTC_STAT_PERS0_MASK);
+
 	switch (rtc_data->clk_src) {
 	case MXS_OSC_24M:
 		/* keep the 24 MHz oscillator running even in power down */
@@ -225,6 +267,9 @@ static void stmp3xxx_alarm_keep_oscillator(const struct stmp3xxx_rtc_data *rtc_d
 	default:
 		break;
 	}
+
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_NEW_SHIFT,
+				STMP3XXX_RTC_STAT_PERS0_MASK);
 }
 
 static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
@@ -233,6 +278,10 @@ static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 
 	stmp3xxx_alarm_keep_oscillator(rtc_data);
 
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_STALE_SHIFT,
+				STMP3XXX_RTC_STAT_PERS0_MASK |
+				STMP3XXX_RTC_STAT_ALARM_MASK);
+
 	if (enabled) {
 		writel(STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE, /* to be able to sleep */
 			rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
@@ -249,6 +298,10 @@ static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 				rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 		writel(0, rtc_data->io + STMP3XXX_RTC_ALARM);
 	}
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_NEW_SHIFT,
+				STMP3XXX_RTC_STAT_PERS0_MASK |
+				STMP3XXX_RTC_STAT_ALARM_MASK);
+
 	return 0;
 }
 
@@ -258,10 +311,16 @@ static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 
 	rtc_tm_to_time(&alm->time, &t);
+
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_STALE_SHIFT,
+				STMP3XXX_RTC_STAT_ALARM_MASK);
+
 	writel(t, rtc_data->io + STMP3XXX_RTC_ALARM);
 
-	stmp3xxx_alarm_irq_enable(dev, alm->enabled);
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_NEW_SHIFT,
+				STMP3XXX_RTC_STAT_ALARM_MASK);
 
+	stmp3xxx_alarm_irq_enable(dev, alm->enabled);
 	return 0;
 }
 
@@ -296,6 +355,13 @@ static ssize_t stmp3xxx_rtc_persist_read(struct file *filep,
 	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 	ssize_t count;
 
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_STALE_SHIFT,
+				STMP3XXX_RTC_STAT_PERS1_MASK |
+				STMP3XXX_RTC_STAT_PERS2_MASK |
+				STMP3XXX_RTC_STAT_PERS3_MASK |
+				STMP3XXX_RTC_STAT_PERS4_MASK |
+				STMP3XXX_RTC_STAT_PERS5_MASK);
+
 	for (count = 0; size; size--, off++, count++)
 		*buf++ = readl(rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + off);
 
@@ -316,6 +382,13 @@ static ssize_t stmp3xxx_rtc_persist_write(struct file *filep,
 	for (count = 0; size; size--, off++, count++)
 		writel(*buf++, rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + off);
 
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_NEW_SHIFT,
+				STMP3XXX_RTC_STAT_PERS1_MASK |
+				STMP3XXX_RTC_STAT_PERS2_MASK |
+				STMP3XXX_RTC_STAT_PERS3_MASK |
+				STMP3XXX_RTC_STAT_PERS4_MASK |
+				STMP3XXX_RTC_STAT_PERS5_MASK);
+
 	return count;
 }
 #endif
@@ -389,7 +462,23 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, rtc_data);
 
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_NEW_SHIFT,
+				STMP3XXX_RTC_STAT_PERS1_MASK |
+				STMP3XXX_RTC_STAT_PERS2_MASK |
+				STMP3XXX_RTC_STAT_PERS3_MASK |
+				STMP3XXX_RTC_STAT_PERS4_MASK |
+				STMP3XXX_RTC_STAT_PERS5_MASK |
+				STMP3XXX_RTC_STAT_ALARM_MASK |
+				STMP3XXX_RTC_STAT_SEC_MASK);
 	mxs_reset_block(rtc_data->io);
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_STALE_SHIFT,
+				STMP3XXX_RTC_STAT_PERS1_MASK |
+				STMP3XXX_RTC_STAT_PERS2_MASK |
+				STMP3XXX_RTC_STAT_PERS3_MASK |
+				STMP3XXX_RTC_STAT_PERS4_MASK |
+				STMP3XXX_RTC_STAT_PERS5_MASK |
+				STMP3XXX_RTC_STAT_ALARM_MASK |
+				STMP3XXX_RTC_STAT_SEC_MASK);
 
 	/*
 	 * configure the RTC to provide the correct time
-- 
1.8.2.rc2

[PATCH v2 9/9] rtc: stmp3xxx: Replace wait_time function

[Steffen Trumtrar]

Replace the wait_time function with the more generic wait_copy_ctrl function.

Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---
 drivers/rtc/rtc-stmp3xxx.c | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index 3de868d..687bcb2 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -179,24 +179,13 @@ static inline void stmp3xxx_wait_copy_ctrl(const struct stmp3xxx_rtc_data *rtc_d
 	}
 }
 
-static void stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
-{
-	/*
-	 * The datasheet doesn't say which way round the
-	 * NEW_REGS/STALE_REGS bitfields go. In fact it's 0x1=P0,
-	 * 0x2=P1, .., 0x20=P5, 0x40=ALARM, 0x80=SECONDS
-	 */
-	while (readl(rtc_data->io + STMP3XXX_RTC_STAT) &
-			(0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT))
-		cpu_relax();
-}
-
 /* Time read/write */
 static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 {
 	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 
-	stmp3xxx_wait_time(rtc_data);
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_STALE_SHIFT,
+				STMP3XXX_RTC_STAT_SEC_MASK);
 	rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_SECONDS), rtc_tm);
 	return 0;
 }
@@ -206,7 +195,8 @@ static int stmp3xxx_rtc_set_mmss(struct device *dev, unsigned long t)
 	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 
 	writel(t, rtc_data->io + STMP3XXX_RTC_SECONDS);
-	stmp3xxx_wait_time(rtc_data);
+	stmp3xxx_wait_copy_ctrl(rtc_data, STMP3XXX_RTC_STAT_NEW_SHIFT,
+				STMP3XXX_RTC_STAT_SEC_MASK);
 	return 0;
 }
 
-- 
1.8.2.rc2