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Subject[RFC PATCH v2] watchdog: sp805: Add clock-frequency property
Date
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.mannam@broadcom.com>
---
drivers/watchdog/sp805_wdt.c | 34 ++++++++++++++++++++++++++--------
1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
index 9849db0..ad5ed64 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
@@ -228,10 +229,27 @@ 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)) {
+ if (adev->dev.of_node) {
+ wdt->clk = devm_clk_get(&adev->dev, NULL);
+ if (IS_ERR(wdt->clk)) {
+ ret = PTR_ERR(wdt->clk);
+ wdt->clk = NULL;
+ } else
+ 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)
+ ret = -ENODEV;
+ }
+
+ if (ret) {
dev_warn(&adev->dev, "Clock not found\n");
- ret = PTR_ERR(wdt->clk);
goto err;
}

--
2.7.4
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