Hi Tony,

On 02/29/2016 04:04 PM, Tony Lindgren wrote:

* Franklin S Cooper Jr [off-list ref] [160225 14:37]:

quoted

The PWMSS local clock gating registers have no real purpose on OMAP ARM
devices. These registers were left over registers from DSP IP where the
PRCM doesn't exist. There is a silicon bug where gating and ungating clocks
don't function properly. TRMs will be update to indicate that these
registers shouldn't be touched.

Therefore, all code that accesses the PWMSS_CLKCONFIG or PWMSS_CLKSTATUS
will be removed by this patch with zero loss of functionality by the ECAP
and EPWM drivers.

@@ -243,40 +240,15 @@ static int ecap_pwm_probe(struct platform_device *pdev)
 	}
 
 	pm_runtime_enable(&pdev->dev);
-	pm_runtime_get_sync(&pdev->dev);
-
-	status = pwmss_submodule_state_change(pdev->dev.parent,
-			PWMSS_ECAPCLK_EN);
-	if (!(status & PWMSS_ECAPCLK_EN_ACK)) {
-		dev_err(&pdev->dev, "PWMSS config space clock enable failed\n");
-		ret = -EINVAL;
-		goto pwmss_clk_failure;
-	}
-
-	pm_runtime_put_sync(&pdev->dev);
 
 	platform_set_drvdata(pdev, pc);
 	return 0;
-
-pwmss_clk_failure:
-	pm_runtime_put_sync(&pdev->dev);
-	pm_runtime_disable(&pdev->dev);
-	pwmchip_remove(&pc->chip);
-	return ret;
 }

Hmm but why are you also removing the pm_runtime calls? Those
actually do take care of gating the clocks via the interconnect
level code that is hwmod in this case.

I removed all PM runtime calls that revolved around
pwmss_submodule_state_change. Originally the driver would do
a pm_runtime_get_sync then call pwmss_submodule_state_change
and then immediately call pm_runtime_put_sync. Without
pwmss_submodule_state_change those calls would be
meaningless.  I also removed pm_runtime calls in error paths
that no longer existed.

Within ecap and epwm driver pm_runtime_get is done when
pwm_enable is called  and pm_runtime_sync calls are done
when pwm_disable is called. Similar pm_runtime_get and
pm_runtime_sync calls are done in functions that ended up
touching register's within the IP.

Regards,

Tony