[PATCH V10 1/3] dt-bindings: rtc: zynqmp: Add clock information

[PATCH V10 1/3] dt-bindings: rtc: zynqmp: Add clock information

[Srinivas Neeli]

Added clock information and deprecated calibration support.

Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
Changes in V10:
-resolved dt_check error.
Changes in V9:
-Updated clock information in clock-names.
Changes in V8:
-None
Changes in V7:
-None
Changes in V6:
-Removed dtc warnings.
Changes in V5:
-Removed quotes and _clk suffix from clocknames.
Changes in V4:
- Deprecated calibrtion support
Changes in V3:
- New patch
---
 .../devicetree/bindings/rtc/xlnx,zynqmp-rtc.yaml     | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/rtc/xlnx,zynqmp-rtc.yaml b/Documentation/devicetree/bindings/rtc/xlnx,zynqmp-rtc.yaml
index bdb72d3ddf2a..7ed0230f6c67 100644
--- a/Documentation/devicetree/bindings/rtc/xlnx,zynqmp-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/xlnx,zynqmp-rtc.yaml
@@ -23,8 +23,15 @@ properties:
   reg:
     maxItems: 1
 
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: rtc
+
   interrupts:
-    minItems: 2
+    maxItems: 2
 
   interrupt-names:
     items:
@@ -39,6 +46,7 @@ properties:
     minimum: 0x1
     maximum: 0x1FFFFF
     default: 0x198233
+    deprecated: true
 
 required:
   - compatible
@@ -61,5 +69,7 @@ examples:
         interrupts = <0 26 4>, <0 27 4>;
         interrupt-names = "alarm", "sec";
         calibration = <0x198233>;
+        clock-names = "rtc";
+        clocks = <&rtc_clk>;
       };
     };
-- 
2.25.1

[PATCH V10 2/3] rtc: zynqmp: Updated calibration value

[Srinivas Neeli]

As per RTC spec default calibration value is 0x7FFF.
We are in process to update the 0x7FFF as default value in
the next version of TRM.

Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
Acked-by: Peter Korsgaard <peter@korsgaard.com>
---
Changes in V10:
-None
Changes in V9:
-None
Changes in V8
-None, just swapped 2/3 and 3/3 patches from V7.
Changes in V7:
-New patch
-TRM not updated yet, Internal design document contains 0x7FFF as
 default value. TRM Will update in next release.
---
 drivers/rtc/rtc-zynqmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
index f440bb52be92..5da33d760419 100644
--- a/drivers/rtc/rtc-zynqmp.c
+++ b/drivers/rtc/rtc-zynqmp.c
@@ -36,7 +36,7 @@
 #define RTC_OSC_EN		BIT(24)
 #define RTC_BATT_EN		BIT(31)
 
-#define RTC_CALIB_DEF		0x198233
+#define RTC_CALIB_DEF		0x7FFF
 #define RTC_CALIB_MASK		0x1FFFFF
 #define RTC_ALRM_MASK          BIT(1)
 #define RTC_MSEC               1000
-- 
2.25.1

[PATCH V10 3/3] rtc: zynqmp: Add calibration set and get support

[Srinivas Neeli]

Zynqmp RTC controller has a calibration feature to compensate
time deviation due to input clock inaccuracy.
Set and get calibration API's are used for setting and getting
calibration value from the controller calibration register.

Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
---
Chanes in V10:
-None
Changes in V9:
-None
Changes in V8:
-None
Changes in V7:
-Removed calibration default value update from this patch.
Changes in V6:
-None
Changes in V5:
-None
Changes in V4:
-Updated MIN and MAX calibration values.
Changes in V3:
-Calculated tick_mult using crystal frequency.
-Calibration register updating based on crystal frequency in probe.
-Supressed MIN an MAX calibration values,Will send separate patch in future.
Changes in V2:
-Removed unused macro.
-Updated code with review comments.
---
 drivers/rtc/rtc-zynqmp.c | 113 ++++++++++++++++++++++++++++++++-------
 1 file changed, 94 insertions(+), 19 deletions(-)

diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
index 5da33d760419..1dd389b891fe 100644
--- a/drivers/rtc/rtc-zynqmp.c
+++ b/drivers/rtc/rtc-zynqmp.c
@@ -6,6 +6,7 @@
  *
  */
 
+#include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
@@ -40,13 +41,19 @@
 #define RTC_CALIB_MASK		0x1FFFFF
 #define RTC_ALRM_MASK          BIT(1)
 #define RTC_MSEC               1000
+#define RTC_FR_MASK		0xF0000
+#define RTC_FR_MAX_TICKS	16
+#define RTC_PPB			1000000000LL
+#define RTC_MIN_OFFSET		-32768000
+#define RTC_MAX_OFFSET		32767000
 
 struct xlnx_rtc_dev {
 	struct rtc_device	*rtc;
 	void __iomem		*reg_base;
 	int			alarm_irq;
 	int			sec_irq;
-	unsigned int		calibval;
+	struct clk		*rtc_clk;
+	unsigned int		freq;
 };
 
 static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
@@ -61,13 +68,6 @@ static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	 */
 	new_time = rtc_tm_to_time64(tm) + 1;
 
-	/*
-	 * Writing into calibration register will clear the Tick Counter and
-	 * force the next second to be signaled exactly in 1 second period
-	 */
-	xrtcdev->calibval &= RTC_CALIB_MASK;
-	writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
-
 	writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
 
 	/*
@@ -173,15 +173,76 @@ static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev)
 	rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL);
 	rtc_ctrl |= RTC_BATT_EN;
 	writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL);
+}
 
-	/*
-	 * Based on crystal freq of 33.330 KHz
-	 * set the seconds counter and enable, set fractions counter
-	 * to default value suggested as per design spec
-	 * to correct RTC delay in frequency over period of time.
+static int xlnx_rtc_read_offset(struct device *dev, long *offset)
+{
+	struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
+	unsigned long long rtc_ppb = RTC_PPB;
+	unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
+	unsigned int calibval;
+	long offset_val;
+
+	calibval = readl(xrtcdev->reg_base + RTC_CALIB_RD);
+	/* Offset with seconds ticks */
+	offset_val = calibval & RTC_TICK_MASK;
+	offset_val = offset_val - RTC_CALIB_DEF;
+	offset_val = offset_val * tick_mult;
+
+	/* Offset with fractional ticks */
+	if (calibval & RTC_FR_EN)
+		offset_val += ((calibval & RTC_FR_MASK) >> RTC_FR_DATSHIFT)
+			* (tick_mult / RTC_FR_MAX_TICKS);
+	*offset = offset_val;
+
+	return 0;
+}
+
+static int xlnx_rtc_set_offset(struct device *dev, long offset)
+{
+	struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
+	unsigned long long rtc_ppb = RTC_PPB;
+	unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
+	unsigned char fract_tick;
+	unsigned int calibval;
+	short int  max_tick;
+	int fract_offset;
+
+	if (offset < RTC_MIN_OFFSET || offset > RTC_MAX_OFFSET)
+		return -ERANGE;
+
+	/* Number ticks for given offset */
+	max_tick = div_s64_rem(offset, tick_mult, &fract_offset);
+
+	/* Number fractional ticks for given offset */
+	if (fract_offset) {
+		if (fract_offset < 0) {
+			fract_offset = fract_offset + tick_mult;
+			max_tick--;
+		}
+		if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) {
+			for (fract_tick = 1; fract_tick < 16; fract_tick++) {
+				if (fract_offset <=
+				    (fract_tick *
+				     (tick_mult / RTC_FR_MAX_TICKS)))
+					break;
+			}
+		}
+	}
+
+	/* Zynqmp RTC uses second and fractional tick
+	 * counters for compensation
 	 */
-	xrtcdev->calibval &= RTC_CALIB_MASK;
-	writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
+	calibval = max_tick + RTC_CALIB_DEF;
+
+	if (fract_tick)
+		calibval |= RTC_FR_EN;
+
+	calibval |= (fract_tick << RTC_FR_DATSHIFT);
+
+	writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
+
+	return 0;
 }
 
 static const struct rtc_class_ops xlnx_rtc_ops = {
@@ -190,6 +251,8 @@ static const struct rtc_class_ops xlnx_rtc_ops = {
 	.read_alarm	  = xlnx_rtc_read_alarm,
 	.set_alarm	  = xlnx_rtc_set_alarm,
 	.alarm_irq_enable = xlnx_rtc_alarm_irq_enable,
+	.read_offset	  = xlnx_rtc_read_offset,
+	.set_offset	  = xlnx_rtc_set_offset,
 };
 
 static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
@@ -255,10 +318,22 @@ static int xlnx_rtc_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = of_property_read_u32(pdev->dev.of_node, "calibration",
-				   &xrtcdev->calibval);
-	if (ret)
-		xrtcdev->calibval = RTC_CALIB_DEF;
+	/* Getting the rtc_clk info */
+	xrtcdev->rtc_clk = devm_clk_get_optional(&pdev->dev, "rtc_clk");
+	if (IS_ERR(xrtcdev->rtc_clk)) {
+		if (PTR_ERR(xrtcdev->rtc_clk) != -EPROBE_DEFER)
+			dev_warn(&pdev->dev, "Device clock not found.\n");
+	}
+	xrtcdev->freq = clk_get_rate(xrtcdev->rtc_clk);
+	if (!xrtcdev->freq) {
+		ret = of_property_read_u32(pdev->dev.of_node, "calibration",
+					   &xrtcdev->freq);
+		if (ret)
+			xrtcdev->freq = RTC_CALIB_DEF;
+	}
+	ret = readl(xrtcdev->reg_base + RTC_CALIB_RD);
+	if (!ret)
+		writel(xrtcdev->freq, (xrtcdev->reg_base + RTC_CALIB_WR));
 
 	xlnx_init_rtc(xrtcdev);
 
-- 
2.25.1

RE: [PATCH V10 3/3] rtc: zynqmp: Add calibration set and get support

[Neeli, Srinivas]

Hi,

Is there any comments on this patch ?.

Thanks
Neeli Srinivas
> -----Original Message-----
> From: Srinivas Neeli <srinivas.neeli@xilinx.com>
> Sent: Sunday, June 26, 2022 12:38 PM
> To: a.zummo@towertech.it; alexandre.belloni@bootlin.com;
> robh+dt@kernel.org; Neeli, Srinivas <srinivas.neeli@amd.com>;
> neelisrinivas18@gmail.com; krzysztof.kozlowski+dt@linaro.org;
> michal.simek@xilinx.com; sgoud@xilinx.com; shubhraj@xilinx.com
> Cc: devicetree@vger.kernel.org; linux-rtc@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; git (AMD-Xilinx)
> <git@amd.com>; git@xilinx.com; Srinivas Neeli <srinivas.neeli@xilinx.com>
> Subject: [PATCH V10 3/3] rtc: zynqmp: Add calibration set and get support
> 
> Zynqmp RTC controller has a calibration feature to compensate time
> deviation due to input clock inaccuracy.
> Set and get calibration API's are used for setting and getting calibration value
> from the controller calibration register.
> 
> Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
> ---
> Chanes in V10:
> -None
> Changes in V9:
> -None
> Changes in V8:
> -None
> Changes in V7:
> -Removed calibration default value update from this patch.
> Changes in V6:
> -None
> Changes in V5:
> -None
> Changes in V4:
> -Updated MIN and MAX calibration values.
> Changes in V3:
> -Calculated tick_mult using crystal frequency.
> -Calibration register updating based on crystal frequency in probe.
> -Supressed MIN an MAX calibration values,Will send separate patch in
> future.
> Changes in V2:
> -Removed unused macro.
> -Updated code with review comments.
> ---
>  drivers/rtc/rtc-zynqmp.c | 113 ++++++++++++++++++++++++++++++++-------
>  1 file changed, 94 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c index
> 5da33d760419..1dd389b891fe 100644
> --- a/drivers/rtc/rtc-zynqmp.c
> +++ b/drivers/rtc/rtc-zynqmp.c
> @@ -6,6 +6,7 @@
>   *
>   */
> 
> +#include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/init.h>
>  #include <linux/io.h>
> @@ -40,13 +41,19 @@
>  #define RTC_CALIB_MASK		0x1FFFFF
>  #define RTC_ALRM_MASK          BIT(1)
>  #define RTC_MSEC               1000
> +#define RTC_FR_MASK		0xF0000
> +#define RTC_FR_MAX_TICKS	16
> +#define RTC_PPB			1000000000LL
> +#define RTC_MIN_OFFSET		-32768000
> +#define RTC_MAX_OFFSET		32767000
> 
>  struct xlnx_rtc_dev {
>  	struct rtc_device	*rtc;
>  	void __iomem		*reg_base;
>  	int			alarm_irq;
>  	int			sec_irq;
> -	unsigned int		calibval;
> +	struct clk		*rtc_clk;
> +	unsigned int		freq;
>  };
> 
>  static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm) @@ -
> 61,13 +68,6 @@ static int xlnx_rtc_set_time(struct device *dev, struct
> rtc_time *tm)
>  	 */
>  	new_time = rtc_tm_to_time64(tm) + 1;
> 
> -	/*
> -	 * Writing into calibration register will clear the Tick Counter and
> -	 * force the next second to be signaled exactly in 1 second period
> -	 */
> -	xrtcdev->calibval &= RTC_CALIB_MASK;
> -	writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
> -
>  	writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
> 
>  	/*
> @@ -173,15 +173,76 @@ static void xlnx_init_rtc(struct xlnx_rtc_dev
> *xrtcdev)
>  	rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL);
>  	rtc_ctrl |= RTC_BATT_EN;
>  	writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL);
> +}
> 
> -	/*
> -	 * Based on crystal freq of 33.330 KHz
> -	 * set the seconds counter and enable, set fractions counter
> -	 * to default value suggested as per design spec
> -	 * to correct RTC delay in frequency over period of time.
> +static int xlnx_rtc_read_offset(struct device *dev, long *offset) {
> +	struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
> +	unsigned long long rtc_ppb = RTC_PPB;
> +	unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
> +	unsigned int calibval;
> +	long offset_val;
> +
> +	calibval = readl(xrtcdev->reg_base + RTC_CALIB_RD);
> +	/* Offset with seconds ticks */
> +	offset_val = calibval & RTC_TICK_MASK;
> +	offset_val = offset_val - RTC_CALIB_DEF;
> +	offset_val = offset_val * tick_mult;
> +
> +	/* Offset with fractional ticks */
> +	if (calibval & RTC_FR_EN)
> +		offset_val += ((calibval & RTC_FR_MASK) >>
> RTC_FR_DATSHIFT)
> +			* (tick_mult / RTC_FR_MAX_TICKS);
> +	*offset = offset_val;
> +
> +	return 0;
> +}
> +
> +static int xlnx_rtc_set_offset(struct device *dev, long offset) {
> +	struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
> +	unsigned long long rtc_ppb = RTC_PPB;
> +	unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
> +	unsigned char fract_tick;
> +	unsigned int calibval;
> +	short int  max_tick;
> +	int fract_offset;
> +
> +	if (offset < RTC_MIN_OFFSET || offset > RTC_MAX_OFFSET)
> +		return -ERANGE;
> +
> +	/* Number ticks for given offset */
> +	max_tick = div_s64_rem(offset, tick_mult, &fract_offset);
> +
> +	/* Number fractional ticks for given offset */
> +	if (fract_offset) {
> +		if (fract_offset < 0) {
> +			fract_offset = fract_offset + tick_mult;
> +			max_tick--;
> +		}
> +		if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) {
> +			for (fract_tick = 1; fract_tick < 16; fract_tick++) {
> +				if (fract_offset <=
> +				    (fract_tick *
> +				     (tick_mult / RTC_FR_MAX_TICKS)))
> +					break;
> +			}
> +		}
> +	}
> +
> +	/* Zynqmp RTC uses second and fractional tick
> +	 * counters for compensation
>  	 */
> -	xrtcdev->calibval &= RTC_CALIB_MASK;
> -	writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
> +	calibval = max_tick + RTC_CALIB_DEF;
> +
> +	if (fract_tick)
> +		calibval |= RTC_FR_EN;
> +
> +	calibval |= (fract_tick << RTC_FR_DATSHIFT);
> +
> +	writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
> +
> +	return 0;
>  }
> 
>  static const struct rtc_class_ops xlnx_rtc_ops = { @@ -190,6 +251,8 @@
> static const struct rtc_class_ops xlnx_rtc_ops = {
>  	.read_alarm	  = xlnx_rtc_read_alarm,
>  	.set_alarm	  = xlnx_rtc_set_alarm,
>  	.alarm_irq_enable = xlnx_rtc_alarm_irq_enable,
> +	.read_offset	  = xlnx_rtc_read_offset,
> +	.set_offset	  = xlnx_rtc_set_offset,
>  };
> 
>  static irqreturn_t xlnx_rtc_interrupt(int irq, void *id) @@ -255,10 +318,22
> @@ static int xlnx_rtc_probe(struct platform_device *pdev)
>  		return ret;
>  	}
> 
> -	ret = of_property_read_u32(pdev->dev.of_node, "calibration",
> -				   &xrtcdev->calibval);
> -	if (ret)
> -		xrtcdev->calibval = RTC_CALIB_DEF;
> +	/* Getting the rtc_clk info */
> +	xrtcdev->rtc_clk = devm_clk_get_optional(&pdev->dev, "rtc_clk");
> +	if (IS_ERR(xrtcdev->rtc_clk)) {
> +		if (PTR_ERR(xrtcdev->rtc_clk) != -EPROBE_DEFER)
> +			dev_warn(&pdev->dev, "Device clock not found.\n");
> +	}
> +	xrtcdev->freq = clk_get_rate(xrtcdev->rtc_clk);
> +	if (!xrtcdev->freq) {
> +		ret = of_property_read_u32(pdev->dev.of_node,
> "calibration",
> +					   &xrtcdev->freq);
> +		if (ret)
> +			xrtcdev->freq = RTC_CALIB_DEF;
> +	}
> +	ret = readl(xrtcdev->reg_base + RTC_CALIB_RD);
> +	if (!ret)
> +		writel(xrtcdev->freq, (xrtcdev->reg_base + RTC_CALIB_WR));
> 
>  	xlnx_init_rtc(xrtcdev);
> 
> --
> 2.25.1

Re: [PATCH V10 1/3] dt-bindings: rtc: zynqmp: Add clock information

[Krzysztof Kozlowski]

On 26/06/2022 09:08, Srinivas Neeli wrote:
> Added clock information and deprecated calibration support.
> 
> Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> ---
> Changes in V10:
> -resolved dt_check error.
> Changes in V9:


Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>


Best regards,
Krzysztof

Re: [PATCH V10 1/3] dt-bindings: rtc: zynqmp: Add clock information

[Alexandre Belloni]

On Sun, 26 Jun 2022 12:38:15 +0530, Srinivas Neeli wrote:
> Added clock information and deprecated calibration support.
> 
> 

Applied, thanks!

[1/3] dt-bindings: rtc: zynqmp: Add clock information
      commit: f69060c14431f476b6993ea92bef77e20437af4e
[2/3] rtc: zynqmp: Updated calibration value
      commit: 85cab027d4e31beb082ec41b71cb8670eeb6fd46
[3/3] rtc: zynqmp: Add calibration set and get support
      commit: 07dcc6f9c76275d6679f28a69e042a2f9dc8f128

Best regards,
-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com