[PATCH V9 1/3] dt-bindings: rtc: zynqmp: Add clock information

[PATCH V9 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 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..9dfe2cc5966a 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_clk";
+        clocks = <&rtc_clk>;
       };
     };
-- 
2.25.1

[PATCH V9 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 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 V9 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>
---
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 V9 1/3] dt-bindings: rtc: zynqmp: Add clock information

[Rob Herring]

On Fri, 24 Jun 2022 17:32:01 +0530, 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 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(-)
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/rtc/xlnx,zynqmp-rtc.example.dtb: rtc@ffa60000: clock-names:0: 'rtc' was expected
	From schema: /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/rtc/xlnx,zynqmp-rtc.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.

Re: [PATCH V9 1/3] dt-bindings: rtc: zynqmp: Add clock information

[Krzysztof Kozlowski]

On 24/06/2022 14:02, 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 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..9dfe2cc5966a 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_clk";
> +        clocks = <&rtc_clk>;

Please test your bindings with `make dt_binding_check` before sending.



Best regards,
Krzysztof