From: <Claudiu.Beznea@microchip.com>
To: <sam@ravnborg.org>
Cc: <lee.jones@linaro.org>, <robh+dt@kernel.org>,
<mark.rutland@arm.com>, <Nicolas.Ferre@microchip.com>,
<alexandre.belloni@bootlin.com>,
<Ludovic.Desroches@microchip.com>, <bbrezillon@kernel.org>,
<airlied@linux.ie>, <daniel@ffwll.ch>, <thierry.reding@gmail.com>,
<devicetree@vger.kernel.org>, <linux-pwm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
<Sandeep.Sheriker@microchip.com>,
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 6/7] drm: atmel-hlcdc: enable sys_clk during initalization.
Date: Fri, 1 Mar 2019 10:07:20 +0000 [thread overview]
Message-ID: <6271a811-9e45-f55c-d53b-b9efe4f13ba4@microchip.com> (raw)
In-Reply-To: <20190228215519.GE30188@ravnborg.org>
On 28.02.2019 23:55, Sam Ravnborg wrote:
> Hi Claudiu
>
> On Wed, Feb 27, 2019 at 04:24:40PM +0000, Claudiu.Beznea@microchip.com wrote:
>> From: Sandeep Sheriker Mallikarjun <sandeepsheriker.mallikarjun@microchip.com>
>>
>> For SAM9X60 SoC, sys_clk is through lcd_gclk clock source and this
>> needs to be enabled before enabling lcd_clk.
>
> We have "ownership" of the clocks in the mfd device.
> So it would make more sense to let the mfd device handle
> the base clocks.
> In other words - what about pushing enable of perigh_clk and sys_clk to
> the mfd driver.
I think this could be achieved, but how is better? To have individual
drivers (in this care I would say, child drivers, like e.g. this lcd
driver) taking decisions on their own for their resources (even if shared)
or to have parents taking decisions for them? Just asking.
>
> This may have the nice side-effect that we avoid
> that both the drm driver and the pwm driver enable/disable the periph_clk
> as it is today.
>
> Another comment - fixed_clksrc is used to determine if sys_clk is enabled.
> But that flag is about the clksource selection, and it is just a coincidence
> that the same flag can be used here.
Yes, agree on this, I took advantage of fixed_clksrc to also enable the
sys_clk based on fixed_clksrc to avoid introducing another member in struct
atmel_hlcdc_dc_desc. At this moment this is valid only for SAM9X60 and I
was thinking that in case some other scenario will appear I will do the
appropriate changes.
> Why we cannot always enable sys_clk? Do we need to do this only
> for sam9x60?
Only SAM9X60 requires this explicitly at probe.
> IF yes, then add a new falg. If no, then skip the flag.
>
> Sam
>
>
>>
>> Signed-off-by: Sandeep Sheriker Mallikarjun <sandeepsheriker.mallikarjun@microchip.com>
>> [claudiu.beznea@microchip.com: add fixed_clksrc checks]
>> Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
>> ---
>> drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c | 19 ++++++++++++++++++-
>> 1 file changed, 18 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
>> index 0be13eceedba..8bf51f853721 100644
>> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
>> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
>> @@ -625,10 +625,18 @@ static int atmel_hlcdc_dc_load(struct drm_device *dev)
>> dc->hlcdc = dev_get_drvdata(dev->dev->parent);
>> dev->dev_private = dc;
>>
>> + if (dc->desc->fixed_clksrc) {
>> + ret = clk_prepare_enable(dc->hlcdc->sys_clk);
>> + if (ret) {
>> + dev_err(dev->dev, "failed to enable sys_clk\n");
>> + goto err_destroy_wq;
>> + }
>> + }
>> +
>> ret = clk_prepare_enable(dc->hlcdc->periph_clk);
>> if (ret) {
>> dev_err(dev->dev, "failed to enable periph_clk\n");
>> - goto err_destroy_wq;
>> + goto err_sys_clk_disable;
>> }
>>
>> pm_runtime_enable(dev->dev);
>> @@ -664,6 +672,9 @@ static int atmel_hlcdc_dc_load(struct drm_device *dev)
>> err_periph_clk_disable:
>> pm_runtime_disable(dev->dev);
>> clk_disable_unprepare(dc->hlcdc->periph_clk);
>> +err_sys_clk_disable:
>> + if (dc->desc->fixed_clksrc)
>> + clk_disable_unprepare(dc->hlcdc->sys_clk);
>>
>> err_destroy_wq:
>> destroy_workqueue(dc->wq);
>> @@ -688,6 +699,8 @@ static void atmel_hlcdc_dc_unload(struct drm_device *dev)
>>
>> pm_runtime_disable(dev->dev);
>> clk_disable_unprepare(dc->hlcdc->periph_clk);
>> + if (dc->desc->fixed_clksrc)
>> + clk_disable_unprepare(dc->hlcdc->sys_clk);
>> destroy_workqueue(dc->wq);
>> }
>>
>> @@ -805,6 +818,8 @@ static int atmel_hlcdc_dc_drm_suspend(struct device *dev)
>> regmap_read(regmap, ATMEL_HLCDC_IMR, &dc->suspend.imr);
>> regmap_write(regmap, ATMEL_HLCDC_IDR, dc->suspend.imr);
>> clk_disable_unprepare(dc->hlcdc->periph_clk);
>> + if (dc->desc->fixed_clksrc)
>> + clk_disable_unprepare(dc->hlcdc->sys_clk);
>>
>> return 0;
>> }
>> @@ -814,6 +829,8 @@ static int atmel_hlcdc_dc_drm_resume(struct device *dev)
>> struct drm_device *drm_dev = dev_get_drvdata(dev);
>> struct atmel_hlcdc_dc *dc = drm_dev->dev_private;
>>
>> + if (dc->desc->fixed_clksrc)
>> + clk_prepare_enable(dc->hlcdc->sys_clk);
>> clk_prepare_enable(dc->hlcdc->periph_clk);
>> regmap_write(dc->hlcdc->regmap, ATMEL_HLCDC_IER, dc->suspend.imr);
>>
>> --
>> 2.7.4
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
next prev parent reply other threads:[~2019-03-01 10:07 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 16:24 [PATCH 0/7] add LCD support for SAM9X60 Claudiu.Beznea
2019-02-27 16:24 ` [PATCH 1/7] drm: atmel-hlcdc: add config option for clock selection Claudiu.Beznea
2019-02-28 21:25 ` Sam Ravnborg
2019-03-01 10:07 ` Claudiu.Beznea
2019-02-28 21:38 ` Sam Ravnborg
2019-03-01 10:06 ` Claudiu.Beznea
2019-02-27 16:24 ` [PATCH 2/7] drm: atmel-hlcdc: avoid initializing cfg with zero Claudiu.Beznea
2019-02-28 21:41 ` Sam Ravnborg
2019-02-27 16:24 ` [PATCH 3/7] dt-bindings: mfd: add bindings for SAM9X60 HLCD controller Claudiu.Beznea
2019-02-27 16:24 ` [PATCH 4/7] mfd: atmel-hlcdc: add compatible " Claudiu.Beznea
2019-02-27 16:24 ` [PATCH 5/7] pwm: atmel-hlcdc: add compatible for SAM9X60 HLCDC's PWM Claudiu.Beznea
2019-03-04 11:05 ` Thierry Reding
2019-02-27 16:24 ` [PATCH 6/7] drm: atmel-hlcdc: enable sys_clk during initalization Claudiu.Beznea
2019-02-28 21:55 ` Sam Ravnborg
2019-03-01 10:07 ` Claudiu.Beznea [this message]
2019-02-27 16:24 ` [PATCH 7/7] drm: atmel-hlcdc: add sam9x60 LCD controller Claudiu.Beznea
2019-02-28 18:21 ` [PATCH 0/7] add LCD support for SAM9X60 Sam Ravnborg
2019-02-28 20:52 ` Alexandre Belloni
2019-02-28 21:13 ` Sam Ravnborg
2019-03-01 10:09 ` Claudiu.Beznea
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6271a811-9e45-f55c-d53b-b9efe4f13ba4@microchip.com \
--to=claudiu.beznea@microchip.com \
--cc=Ludovic.Desroches@microchip.com \
--cc=Nicolas.Ferre@microchip.com \
--cc=Sandeep.Sheriker@microchip.com \
--cc=airlied@linux.ie \
--cc=alexandre.belloni@bootlin.com \
--cc=bbrezillon@kernel.org \
--cc=daniel@ffwll.ch \
--cc=devicetree@vger.kernel.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=lee.jones@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pwm@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=robh+dt@kernel.org \
--cc=sam@ravnborg.org \
--cc=thierry.reding@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).