[PATCH v3 1/1] driver: watchdog: get platform clock from dt file

[Stefan Roese]

On 06.04.20 09:15, Rayagonda Kokatanur wrote:
> Get the watchdog platform clock from the DTS file
> using clk subsystem and use the same for calculating
> ticks in msec.
> 
> Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur at broadcom.com>
> Signed-off-by: Bharat Kumar Reddy Gooty <bharat.gooty at broadcom.com>
> ---
> Changes from v2:
>   -Address review comments from Stefan Roese,
>    Use clk subsystem to get the base frequency of device instead
>    of dt parameter "clk_mhz".
> 
> Changes from v1:
>   -Address review comments from Stefan Roese,
>    Remove default timeout reading in probe() as it is read in include/wdt.h.
>    Add paranthesis on multi-line statements.
> 
>   drivers/watchdog/sp805_wdt.c | 19 +++++++++++++++++--
>   1 file changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
> index ca3ccbe76c..d377ae0fc5 100644
> --- a/drivers/watchdog/sp805_wdt.c
> +++ b/drivers/watchdog/sp805_wdt.c
> @@ -7,6 +7,7 @@
>   
>   #include <asm/io.h>
>   #include <common.h>
> +#include <clk.h>
>   #include <dm/device.h>
>   #include <dm/fdtaddr.h>
>   #include <dm/read.h>
> @@ -34,6 +35,7 @@ DECLARE_GLOBAL_DATA_PTR;
>   
>   struct sp805_wdt_priv {
>   	void __iomem *reg;
> +	unsigned long clk_rate;
>   };
>   
>   static int sp805_wdt_reset(struct udevice *dev)
> @@ -63,8 +65,13 @@ static int sp805_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
>   	 * set 120s, the gd->bus_clk is less than 1145MHz, the load_value will
>   	 * not overflow.
>   	 */
> -	load_value = (gd->bus_clk) /
> -		(2 * 1000 * SYS_FSL_WDT_CLK_DIV) * load_time;
> +	if (gd->bus_clk) {
> +		load_value = (gd->bus_clk) /
> +			(2 * 1000 * SYS_FSL_WDT_CLK_DIV) * load_time;
> +	} else {
> +		/* platform provide clk */
> +		load_value = (timeout / 2) * (priv->clk_rate / 1000);
> +	}
>   
>   	writel(UNLOCK, priv->reg + WDTLOCK);
>   	writel(load_value, priv->reg + WDTLOAD);
> @@ -105,11 +112,19 @@ static int sp805_wdt_probe(struct udevice *dev)
>   static int sp805_wdt_ofdata_to_platdata(struct udevice *dev)
>   {
>   	struct sp805_wdt_priv *priv = dev_get_priv(dev);
> +	struct clk clk;
> +	int ret;
>   
>   	priv->reg = (void __iomem *)dev_read_addr(dev);
>   	if (IS_ERR(priv->reg))
>   		return PTR_ERR(priv->reg);
>   
> +	ret = clk_get_by_index(dev, 0, &clk);
> +	if (!ret)
> +		priv->clk_rate = clk_get_rate(&clk);
> +	else
> +		return -EINVAL;
> +

Thanks for addresses this. Looks much better now, without all the
ad-hoc DT bindings.

Though I suspect that some boards using this WDT driver do not fully
support the CLK API for this device. That's why we still have this
"bus_clk" in global-data here. Some NXP folks might test and report
if this works for them. Otherwise sp805_wdt_ofdata_to_platdata() should
not fail if clk_get_by_index() returns with error.

Thanks,
Stefan