Re: [RFC PATCH v3] watchdog: sp805: Add clock-frequency property

[Guenter Roeck]

On 07/10/2018 01:44 AM, Srinath Mannam wrote:

When using ACPI node, binding clock devices are
not available as device tree, So clock-frequency
property given in _DSD object of ACPI device is
used to calculate Watchdog rate.

Signed-off-by: Srinath Mannam <srinath.man...@broadcom.com>

Please resend as non-RFC and add a note in the description indicating
that there is no formal review process for _DSD properties.

Thanks,
Guenter

---
  drivers/watchdog/sp805_wdt.c | 35 +++++++++++++++++++++++++----------
  1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
index 9849db0..a896b1c 100644
--- a/drivers/watchdog/sp805_wdt.c
+++ b/drivers/watchdog/sp805_wdt.c
@@ -11,6 +11,7 @@
   * warranty of any kind, whether express or implied.
   */

+#include <linux/acpi.h>

  #include <linux/device.h>
  #include <linux/resource.h>
  #include <linux/amba/bus.h>
@@ -22,6 +23,7 @@
  #include <linux/math64.h>
  #include <linux/module.h>
  #include <linux/moduleparam.h>
+#include <linux/of.h>
  #include <linux/pm.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
@@ -65,6 +67,7 @@ struct sp805_wdt {
        spinlock_t                      lock;
        void __iomem                    *base;
        struct clk                      *clk;
+       u64                             rate;
        struct amba_device              *adev;
        unsigned int                    load_val;
  };
@@ -80,7 +83,7 @@ static int wdt_setload(struct watchdog_device *wdd, unsigned 
int timeout)
        struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
        u64 load, rate;

- rate = clk_get_rate(wdt->clk);

+       rate = wdt->rate;

/*

         * sp805 runs counter with given value twice, after the end of first
@@ -106,9 +109,7 @@ static int wdt_setload(struct watchdog_device *wdd, 
unsigned int timeout)
  static unsigned int wdt_timeleft(struct watchdog_device *wdd)
  {
        struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
-       u64 load, rate;
-
-       rate = clk_get_rate(wdt->clk);
+       u64 load;

spin_lock(&wdt->lock);

        load = readl_relaxed(wdt->base + WDTVALUE);
@@ -118,7 +119,7 @@ static unsigned int wdt_timeleft(struct watchdog_device 
*wdd)
                load += wdt->load_val + 1;
        spin_unlock(&wdt->lock);

- return div_u64(load, rate);

+       return div_u64(load, wdt->rate);
  }

static int

@@ -228,11 +229,25 @@ sp805_wdt_probe(struct amba_device *adev, const struct 
amba_id *id)
        if (IS_ERR(wdt->base))
                return PTR_ERR(wdt->base);

- wdt->clk = devm_clk_get(&adev->dev, NULL);

-       if (IS_ERR(wdt->clk)) {
-               dev_warn(&adev->dev, "Clock not found\n");
-               ret = PTR_ERR(wdt->clk);
-               goto err;
+       if (adev->dev.of_node) {
+               wdt->clk = devm_clk_get(&adev->dev, NULL);
+               if (IS_ERR(wdt->clk)) {
+                       dev_err(&adev->dev, "Clock not found\n");
+                       return PTR_ERR(wdt->clk);
+               }
+               wdt->rate = clk_get_rate(wdt->clk);
+       } else if (has_acpi_companion(&adev->dev)) {
+               /*
+                * When Driver probe with ACPI device, clock devices
+                * are not available, so watchdog rate get from
+                * clock-frequency property given in _DSD object.
+                */
+               device_property_read_u64(&adev->dev, "clock-frequency",
+                                        &wdt->rate);
+               if (!wdt->rate) {
+                       dev_err(&adev->dev, "no clock-frequency property\n");
+                       return -ENODEV;
+               }
        }

wdt->adev = adev;