Re: [PATCHv4] watchdog: xilinx: Add clock support

From: Shubhrajyoti Datta <hidden>
Date: 2016-08-12 06:42:21
Also in: linux-watchdog
Subsystem: the rest, watchdog device drivers, xilinx watchdog driver · Maintainers: Linus Torvalds, Wim Van Sebroeck, Guenter Roeck, Srinivas Neeli

Possibly related (same subject, not in this thread)

2016-08-12 · Re: [PATCHv4] watchdog: xilinx: Add clock support · Shubhrajyoti Datta <hidden>
2016-08-12 · Re: [PATCHv4] watchdog: xilinx: Add clock support · Guenter Roeck <hidden>
2016-08-12 · [PATCHv4] watchdog: xilinx: Add clock support · Shubhrajyoti Datta <hidden>

[...]


The clock is optional. Why print anything ?

I am not a friend of logging noise, and I think this is just noise.
Would you want such a message printed for each optional property ?

Guenter

sure patch below


From: Shubhrajyoti Datta <redacted>
Subject: [PATCH] watchdog: xilinx: Add clock support

Add support for the clock. Currently we enable
at probe and relinquish at remove.

Reviewed-by: Guenter Roeck <redacted>
Acked-by: SÃ¶ren Brinkmann <redacted>
Signed-off-by: Shubhrajyoti Datta <redacted>
---
v2:
fix spaces and error path.
v3
do not fail existing dts

v4:
fix the error prints as the clock is optional

 .../devicetree/bindings/watchdog/of-xilinx-wdt.txt |  3 +++
 drivers/watchdog/of_xilinx_wdt.c                   | 25 ++++++++++++++++++++--
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/watchdog/of-xilinx-wdt.txt

b/Documentation/devicetree/bindings/watchdog/of-xilinx-wdt.txt
index 6d63782..c6ae9c9 100644

--- a/Documentation/devicetree/bindings/watchdog/of-xilinx-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/of-xilinx-wdt.txt

@@ -7,6 +7,8 @@ Required properties:
 - reg : Physical base address and size

 Optional properties:
+- clocks : Input clock specifier. Refer to common clock
+  bindings.
 - clock-frequency : Frequency of clock in Hz
 - xlnx,wdt-enable-once : 0 - Watchdog can be restarted
   1 - Watchdog can be enabled just once

@@ -17,6 +19,7 @@ Example:
 axi-timebase-wdt@40100000 {
  clock-frequency = <50000000>;
  compatible = "xlnx,xps-timebase-wdt-1.00.a";
+ clocks = <&clkc 15>;
  reg = <0x40100000 0x10000>;
  xlnx,wdt-enable-once = <0x0>;
  xlnx,wdt-interval = <0x1b>;

diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
index b2e1b4c..fae7fe9 100644
--- a/drivers/watchdog/of_xilinx_wdt.c
+++ b/drivers/watchdog/of_xilinx_wdt.c

@@ -10,6 +10,7 @@
  * 2 of the License, or (at your option) any later version.
  */

+#include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/types.h>

@@ -45,6 +46,7 @@ struct xwdt_device {
  u32 wdt_interval;
  spinlock_t spinlock;
  struct watchdog_device xilinx_wdt_wdd;
+ struct clk *clk;
 };

 static int xilinx_wdt_start(struct watchdog_device *wdd)

@@ -195,16 +197,30 @@ static int xwdt_probe(struct platform_device *pdev)
  spin_lock_init(&xdev->spinlock);
  watchdog_set_drvdata(xilinx_wdt_wdd, xdev);

+ xdev->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(xdev->clk)) {
+ if (PTR_ERR(xdev->clk) == -ENOENT)
+ xdev->clk = NULL;
+ else
+ return PTR_ERR(xdev->clk);
+ }
+
+ rc = clk_prepare_enable(xdev->clk);
+ if (rc) {
+ dev_err(&pdev->dev, "unable to enable clock\n");
+ return rc;
+ }
+
  rc = xwdt_selftest(xdev);
  if (rc == XWT_TIMER_FAILED) {
  dev_err(&pdev->dev, "SelfTest routine error\n");
- return rc;
+ goto err_clk_disable;
  }

  rc = watchdog_register_device(xilinx_wdt_wdd);
  if (rc) {
  dev_err(&pdev->dev, "Cannot register watchdog (err=%d)\n", rc);
- return rc;
+ goto err_clk_disable;
  }

  dev_info(&pdev->dev, "Xilinx Watchdog Timer at %p with timeout %ds\n",

@@ -213,6 +229,10 @@ static int xwdt_probe(struct platform_device *pdev)
  platform_set_drvdata(pdev, xdev);

  return 0;
+err_clk_disable:
+ clk_disable_unprepare(xdev->clk);
+
+ return rc;
 }

 static int xwdt_remove(struct platform_device *pdev)

@@ -220,6 +240,7 @@ static int xwdt_remove(struct platform_device *pdev)
  struct xwdt_device *xdev = platform_get_drvdata(pdev);

  watchdog_unregister_device(&xdev->xilinx_wdt_wdd);
+ clk_disable_unprepare(xdev->clk);

  return 0;
 }

-- 
2.1.1
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