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Date:   Wed, 24 Jan 2018 10:32:43 +0100
From:   Ladislav Michl <ladis@linux-mips.org>
To:     Keerthy <j-keerthy@ti.com>
Cc:     daniel.lezcano@linaro.org, thierry.reding@gmail.com,
        tony@atomide.com, aaro.koskinen@iki.fi,
        Claudiu.Beznea@microchip.com, narmstrong@baylibre.com,
        linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        sebastian.reichel@collabora.co.uk, linux-omap@vger.kernel.org,
        robh+dt@kernel.org, t-kristo@ti.com, grygorii.strashko@ti.com
Subject: Re: [PATCH v8 8/9] pwm: pwm-omap-dmtimer: Adapt driver to utilize
 dmtimer pdata ops
Message-ID: <20180124093243.GA18581@lenoch>
References: <1516772680-28256-1-git-send-email-j-keerthy@ti.com>
 <20180124072432.GA11294@lenoch>
 <e90aed55-e8db-e849-0e07-cbeb453b583c@ti.com>
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In-Reply-To: <e90aed55-e8db-e849-0e07-cbeb453b583c@ti.com>
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On Wed, Jan 24, 2018 at 01:58:19PM +0530, Keerthy wrote:
> On Wednesday 24 January 2018 12:54 PM, Ladislav Michl wrote:
> > Keerthy,
> > 
> > On Wed, Jan 24, 2018 at 11:14:40AM +0530, Keerthy wrote:
> >> Adapt driver to utilize dmtimer pdata ops instead of pdata-quirks.
> >>
> >> Signed-off-by: Keerthy <j-keerthy@ti.com>
> >> Acked-by: Neil Armstrong <narmstrong@baylibre.com>
> >> Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
> >> ---
> >>
> >> Changes in v8:
> >>
> >>   * Added of_node_put call in success case of probe.
> >>
> >> Boot tested on am437x-gp-evm and dra7xx-evm.
> >> Also compile tested omap1_defconfig with other patches of v7
> >> posted here:
> >>
> >> https://www.spinics.net/lists/linux-omap/msg141100.html
> >>
> >> With v8 version of Patch 8/9.
> >>
> >>  drivers/pwm/pwm-omap-dmtimer.c | 68 ++++++++++++++++++++++++++----------------
> >>  1 file changed, 42 insertions(+), 26 deletions(-)
> >>
> >> diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
> >> index 5ad42f3..c00e474 100644
> >> --- a/drivers/pwm/pwm-omap-dmtimer.c
> >> +++ b/drivers/pwm/pwm-omap-dmtimer.c
> >> @@ -23,6 +23,7 @@
> >>  #include <linux/mutex.h>
> >>  #include <linux/of.h>
> >>  #include <linux/of_platform.h>
> >> +#include <linux/platform_data/dmtimer-omap.h>
> >>  #include <linux/platform_data/pwm_omap_dmtimer.h>
> >>  #include <linux/platform_device.h>
> >>  #include <linux/pm_runtime.h>
> >> @@ -37,7 +38,7 @@ struct pwm_omap_dmtimer_chip {
> >>  	struct pwm_chip chip;
> >>  	struct mutex mutex;
> >>  	pwm_omap_dmtimer *dm_timer;
> >> -	struct pwm_omap_dmtimer_pdata *pdata;
> >> +	struct omap_dm_timer_ops *pdata;
> >>  	struct platform_device *dm_timer_pdev;
> >>  };
> >>  
> >> @@ -242,19 +243,35 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
> >>  {
> >>  	struct device_node *np = pdev->dev.of_node;
> >>  	struct device_node *timer;
> >> +	struct platform_device *timer_pdev;
> >>  	struct pwm_omap_dmtimer_chip *omap;
> >> -	struct pwm_omap_dmtimer_pdata *pdata;
> >> +	struct dmtimer_platform_data *timer_pdata;
> >> +	struct omap_dm_timer_ops *pdata;
> >>  	pwm_omap_dmtimer *dm_timer;
> >>  	u32 v;
> >> -	int status;
> >> +	int status, ret = 0;
> >>  
> >> -	pdata = dev_get_platdata(&pdev->dev);
> >> -	if (!pdata) {
> >> -		dev_err(&pdev->dev, "Missing dmtimer platform data\n");
> >> -		return -EINVAL;
> >> +	timer = of_parse_phandle(np, "ti,timers", 0);
> >> +	if (!timer)
> >> +		return -ENODEV;
> >> +
> >> +	timer_pdev = of_find_device_by_node(timer);
> >> +	if (!timer_pdev) {
> >> +		dev_err(&pdev->dev, "Unable to find Timer pdev\n");
> >> +		ret = -ENODEV;
> >> +		goto put;
> >>  	}
> >>  
> >> -	if (!pdata->request_by_node ||
> >> +	timer_pdata = dev_get_platdata(&timer_pdev->dev);
> >> +	if (!timer_pdata) {
> >> +		dev_err(&pdev->dev, "dmtimer pdata structure NULL\n");
> >> +		ret = -EINVAL;
> >> +		goto put;
> >> +	}
> >> +
> >> +	pdata = timer_pdata->timer_ops;
> >> +
> >> +	if (!pdata || !pdata->request_by_node ||
> >>  	    !pdata->free ||
> >>  	    !pdata->enable ||
> >>  	    !pdata->disable ||
> >> @@ -267,37 +284,32 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
> >>  	    !pdata->set_prescaler ||
> >>  	    !pdata->write_counter) {
> >>  		dev_err(&pdev->dev, "Incomplete dmtimer pdata structure\n");
> >> -		return -EINVAL;
> >> +		ret = -EINVAL;
> >> +		goto put;
> >>  	}
> >>  
> >> -	timer = of_parse_phandle(np, "ti,timers", 0);
> >> -	if (!timer)
> >> -		return -ENODEV;
> >> -
> >>  	if (!of_get_property(timer, "ti,timer-pwm", NULL)) {
> >>  		dev_err(&pdev->dev, "Missing ti,timer-pwm capability\n");
> >> -		return -ENODEV;
> >> +		ret = -ENODEV;
> >> +		goto put;
> > 
> > Should we call of_node_put() even from here? of_get_property() failed, so
> > reference was not updated.
> 
> The of_node_put to balance the of_parse_handle called for timer. I hope
> that is what you wanted to check right?

Right, your code does it already, so please ignore my previous comment.

> > 
> >>  	}
> >>  
> >>  	dm_timer = pdata->request_by_node(timer);
> > 
> > And timer seems to be used only here, so calling
> > 	of_node_put(timer);
> > just here should be enough.
> 
> Okay yes. This can be optimized. of_node_put(timer); can be called
> here and the instances below need not have that additional step.

Yes, thank you. Then I'll send rebased patches.

> >> -	if (!dm_timer)
> >> -		return -EPROBE_DEFER;
> >> +	if (!dm_timer) {
> >> +		ret = -EPROBE_DEFER;
> >> +		goto put;
> >> +	}
> >>  
> >>  	omap = devm_kzalloc(&pdev->dev, sizeof(*omap), GFP_KERNEL);
> >>  	if (!omap) {
> >>  		pdata->free(dm_timer);
> >> -		return -ENOMEM;
> >> +		ret = -ENOMEM;
> >> +		goto put;
> >>  	}
> >>  
> >>  	omap->pdata = pdata;
> >>  	omap->dm_timer = dm_timer;
> >> -
> >> -	omap->dm_timer_pdev = of_find_device_by_node(timer);
> >> -	if (!omap->dm_timer_pdev) {
> >> -		dev_err(&pdev->dev, "Unable to find timer pdev\n");
> >> -		omap->pdata->free(dm_timer);
> >> -		return -EINVAL;
> >> -	}
> >> +	omap->dm_timer_pdev = timer_pdev;
> >>  
> >>  	/*
> >>  	 * Ensure that the timer is stopped before we allow PWM core to call
> >> @@ -326,12 +338,16 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
> >>  	if (status < 0) {
> >>  		dev_err(&pdev->dev, "failed to register PWM\n");
> >>  		omap->pdata->free(omap->dm_timer);
> >> -		return status;
> >> +		ret = status;
> >> +		goto put;
> >>  	}
> >>  
> >>  	platform_set_drvdata(pdev, omap);
> >>  
> >> -	return 0;
> >> +put:
> >> +	of_node_put(timer);
> >> +
> >> +	return ret;
> >>  }
> >>  
> >>  static int pwm_omap_dmtimer_remove(struct platform_device *pdev)
> >> -- 
> >> 1.9.1