On Fri, Jul 05, 2019 at 11:46:02AM +0000, Melin Tomas wrote:
> Timeout calculation needs clock frequency, so init clock and calculate
> prescaler value eariler in the probe.
>
earlier; also in subject line
> Preparational step for calculating maximum and minimum timeout values
> for driver.
>
> Signed-off-by: Tomas Melin <tomas.melin@xxxxxxxxxxx>
> ---
> drivers/watchdog/cadence_wdt.c | 32 ++++++++++++++++----------------
> 1 file changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/watchdog/cadence_wdt.c b/drivers/watchdog/cadence_wdt.c
> index c3924356d173..415bd6dd1edb 100644
> --- a/drivers/watchdog/cadence_wdt.c
> +++ b/drivers/watchdog/cadence_wdt.c
> @@ -295,6 +295,22 @@ static int cdns_wdt_probe(struct platform_device *pdev)
> if (!wdt)
> return -ENOMEM;
>
> + wdt->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(wdt->clk)) {
> + dev_err(&pdev->dev, "input clock not found\n");
> + ret = PTR_ERR(wdt->clk);
> + return ret;
return PTR_ERR(wdt->clk);
[ ok, that is from the old code ... ]
> + }
> +
> + clock_f = clk_get_rate(wdt->clk);
> + if (clock_f <= CDNS_WDT_CLK_75MHZ) {
> + wdt->prescaler = CDNS_WDT_PRESCALE_512;
> + wdt->ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_512;
> + } else {
> + wdt->prescaler = CDNS_WDT_PRESCALE_4096;
> + wdt->ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_4096;
> + }
> +
> cdns_wdt_device = &wdt->cdns_wdt_device;
> cdns_wdt_device->info = &cdns_wdt_info;
> cdns_wdt_device->ops = &cdns_wdt_ops;
> @@ -334,28 +350,12 @@ static int cdns_wdt_probe(struct platform_device *pdev)
> watchdog_stop_on_reboot(cdns_wdt_device);
> watchdog_set_drvdata(cdns_wdt_device, wdt);
>
> - wdt->clk = devm_clk_get(&pdev->dev, NULL);
> - if (IS_ERR(wdt->clk)) {
> - dev_err(&pdev->dev, "input clock not found\n");
> - ret = PTR_ERR(wdt->clk);
> - return ret;
> - }
> -
> ret = clk_prepare_enable(wdt->clk);
> if (ret) {
> dev_err(&pdev->dev, "unable to enable clock\n");
> return ret;
> }
>
The substantial difference here is that clk_prepare_enable() was called
before the actual clock rate was retrieved. I don't know if that makes
a substantial difference, but on the other side I don't see why the above
code isn't moved as well. What I _do_ see, however, is that this patch
isn't based on the latest mainline kenrel, since mainline has a call to
devm_add_action_or_reset() after clk_prepare_enable(). Please rebase.
> - clock_f = clk_get_rate(wdt->clk);
> - if (clock_f <= CDNS_WDT_CLK_75MHZ) {
> - wdt->prescaler = CDNS_WDT_PRESCALE_512;
> - wdt->ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_512;
> - } else {
> - wdt->prescaler = CDNS_WDT_PRESCALE_4096;
> - wdt->ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_4096;
> - }
> -
> spin_lock_init(&wdt->io_lock);
>
> ret = watchdog_register_device(cdns_wdt_device);
