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From: Daniel Vetter <daniel@ffwll.ch>
To: Daniel Kurtz <djkurtz@chromium.org>
Cc: "Emil Velikov" <emil.l.velikov@gmail.com>,
	"Mark Rutland" <mark.rutland@arm.com>,
	stonea168@163.com,
	"ML dri-devel" <dri-devel@lists.freedesktop.org>,
	"Ajay Kumar" <ajaykumar.rs@samsung.com>,
	"Vincent Palatin" <vpalatin@chromium.org>,
	"cawa cheng" <cawa.cheng@mediatek.com>,
	"Yingjoe Chen" <yingjoe.chen@mediatek.com>,
	"Thierry Reding" <treding@nvidia.com>,
	devicetree <devicetree@vger.kernel.org>,
	"Jitao Shi" <jitao.shi@mediatek.com>,
	"Pawel Moll" <pawel.moll@arm.com>,
	"Ian Campbell" <ijc+devicetree@hellion.org.uk>,
	"Rob Herring" <robh+dt@kernel.org>,
	"moderated list:ARM/Mediatek SoC support"
	<linux-mediatek@lists.infradead.org>,
	"Russell King" <rmk+kernel@arm.linux.org.uk>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Eddie Huang (黃智傑)" <eddie.huang@mediatek.com>,
	LAKML <linux-arm-kernel@lists.infradead.org>,
	"Rahul Sharma" <rahul.sharma@samsung.com>,
	srv_heupstream <srv_heupstream@mediatek.com>,
	"Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>,
	"Sascha Hauer" <kernel@pengutronix.de>,
	"Kumar Gala" <galak@codeaurora.org>,
	"Andy Yan" <andy.yan@rock-chips.com>
Subject: Re: [PATCH 2/2 v16] drm/bridge: Add I2C based driver for ps8640 bridge
Date: Tue, 12 Jul 2016 12:13:52 +0200	[thread overview]
Message-ID: <CAKMK7uEkUOq1CB3tj_1Qx50fBpw9B39+c3asX6MPNexT=dv9fA@mail.gmail.com> (raw)
In-Reply-To: <CAGS+omDsDS5tx=+Efq8LWNd3-asU4r2h=-AE6vdKgfG-p6vdAA@mail.gmail.com>

On Wed, Jun 29, 2016 at 6:31 AM, Daniel Kurtz <djkurtz@chromium.org> wrote:
> On Fri, Jun 17, 2016 at 3:14 AM, Emil Velikov <emil.l.velikov@gmail.com> wrote:
>>> +static ssize_t ps8640_update_fw_store(struct device *dev,
>>> +                                     struct device_attribute *attr,
>>> +                                     const char *buf, size_t count)
>>> +{
>>> +       struct i2c_client *client = to_i2c_client(dev);
>>> +       struct ps8640 *ps_bridge = i2c_get_clientdata(client);
>>> +       const struct firmware *fw;
>>> +       int error;
>>> +
>>> +       error = request_firmware(&fw, PS_FW_NAME, dev);
>> Can the device operate without a firmware ? If not, why is the
>> firmware loaded so later/after user interaction (via sysfs) ? I don't
>> recall any other driver in DRM to use such an approach.
>
> The PS8640 has internal flash, so it should always already have a
> working firmware.
> This sysfs interface is useful for user space initiated field firmware updates.

Might be better to just do a request_firmware on driver load, and
simply proceed if it's not there. Adding a sysfs interface (which is
abi) seems way too much overkill for this imo. If you want to upgrade
the firmware you can then just drop it into the right directory, with
no further interaction needed.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

WARNING: multiple messages have this Message-ID (diff)
From: Daniel Vetter <daniel@ffwll.ch>
To: Daniel Kurtz <djkurtz@chromium.org>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
	stonea168@163.com,
	"ML dri-devel" <dri-devel@lists.freedesktop.org>,
	"Ajay Kumar" <ajaykumar.rs@samsung.com>,
	"Vincent Palatin" <vpalatin@chromium.org>,
	"cawa cheng" <cawa.cheng@mediatek.com>,
	"Russell King" <rmk+kernel@arm.linux.org.uk>,
	"Thierry Reding" <treding@nvidia.com>,
	devicetree <devicetree@vger.kernel.org>,
	"Jitao Shi" <jitao.shi@mediatek.com>,
	"Pawel Moll" <pawel.moll@arm.com>,
	"Ian Campbell" <ijc+devicetree@hellion.org.uk>,
	"Rob Herring" <robh+dt@kernel.org>,
	"moderated list:ARM/Mediatek SoC support"
	<linux-mediatek@lists.infradead.org>,
	"Yingjoe Chen" <yingjoe.chen@mediatek.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Eddie Huang (黃智傑)" <eddie.huang@mediatek.com>,
	LAKML <linux-arm-kernel@lists.infradead.org>,
	"Rahul Sharma" <rahul.sharma@samsung.com>,
	srv_heupstream <srv_heupstream@mediatek.com>
Subject: Re: [PATCH 2/2 v16] drm/bridge: Add I2C based driver for ps8640 bridge
Date: Tue, 12 Jul 2016 12:13:52 +0200	[thread overview]
Message-ID: <CAKMK7uEkUOq1CB3tj_1Qx50fBpw9B39+c3asX6MPNexT=dv9fA@mail.gmail.com> (raw)
In-Reply-To: <CAGS+omDsDS5tx=+Efq8LWNd3-asU4r2h=-AE6vdKgfG-p6vdAA@mail.gmail.com>

On Wed, Jun 29, 2016 at 6:31 AM, Daniel Kurtz <djkurtz@chromium.org> wrote:
> On Fri, Jun 17, 2016 at 3:14 AM, Emil Velikov <emil.l.velikov@gmail.com> wrote:
>>> +static ssize_t ps8640_update_fw_store(struct device *dev,
>>> +                                     struct device_attribute *attr,
>>> +                                     const char *buf, size_t count)
>>> +{
>>> +       struct i2c_client *client = to_i2c_client(dev);
>>> +       struct ps8640 *ps_bridge = i2c_get_clientdata(client);
>>> +       const struct firmware *fw;
>>> +       int error;
>>> +
>>> +       error = request_firmware(&fw, PS_FW_NAME, dev);
>> Can the device operate without a firmware ? If not, why is the
>> firmware loaded so later/after user interaction (via sysfs) ? I don't
>> recall any other driver in DRM to use such an approach.
>
> The PS8640 has internal flash, so it should always already have a
> working firmware.
> This sysfs interface is useful for user space initiated field firmware updates.

Might be better to just do a request_firmware on driver load, and
simply proceed if it's not there. Adding a sysfs interface (which is
abi) seems way too much overkill for this imo. If you want to upgrade
the firmware you can then just drop it into the right directory, with
no further interaction needed.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

WARNING: multiple messages have this Message-ID (diff)
From: daniel@ffwll.ch (Daniel Vetter)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2 v16] drm/bridge: Add I2C based driver for ps8640 bridge
Date: Tue, 12 Jul 2016 12:13:52 +0200	[thread overview]
Message-ID: <CAKMK7uEkUOq1CB3tj_1Qx50fBpw9B39+c3asX6MPNexT=dv9fA@mail.gmail.com> (raw)
In-Reply-To: <CAGS+omDsDS5tx=+Efq8LWNd3-asU4r2h=-AE6vdKgfG-p6vdAA@mail.gmail.com>

On Wed, Jun 29, 2016 at 6:31 AM, Daniel Kurtz <djkurtz@chromium.org> wrote:
> On Fri, Jun 17, 2016 at 3:14 AM, Emil Velikov <emil.l.velikov@gmail.com> wrote:
>>> +static ssize_t ps8640_update_fw_store(struct device *dev,
>>> +                                     struct device_attribute *attr,
>>> +                                     const char *buf, size_t count)
>>> +{
>>> +       struct i2c_client *client = to_i2c_client(dev);
>>> +       struct ps8640 *ps_bridge = i2c_get_clientdata(client);
>>> +       const struct firmware *fw;
>>> +       int error;
>>> +
>>> +       error = request_firmware(&fw, PS_FW_NAME, dev);
>> Can the device operate without a firmware ? If not, why is the
>> firmware loaded so later/after user interaction (via sysfs) ? I don't
>> recall any other driver in DRM to use such an approach.
>
> The PS8640 has internal flash, so it should always already have a
> working firmware.
> This sysfs interface is useful for user space initiated field firmware updates.

Might be better to just do a request_firmware on driver load, and
simply proceed if it's not there. Adding a sysfs interface (which is
abi) seems way too much overkill for this imo. If you want to upgrade
the firmware you can then just drop it into the right directory, with
no further interaction needed.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

  reply	other threads:[~2016-07-12 10:13 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-02  9:57 [PATCH 1/2 v16] Documentation: bridge: Add documentation for ps8640 DT properties Jitao Shi
2016-06-02  9:57 ` Jitao Shi
2016-06-02  9:57 ` Jitao Shi
2016-06-02  9:57 ` [PATCH 2/2 v16] drm/bridge: Add I2C based driver for ps8640 bridge Jitao Shi
2016-06-02  9:57   ` Jitao Shi
2016-06-02  9:57   ` Jitao Shi
2016-06-14  8:09   ` Daniel Kurtz
2016-06-14  8:09     ` Daniel Kurtz
2016-06-14  8:09     ` Daniel Kurtz
2016-06-16 19:14   ` Emil Velikov
2016-06-16 19:14     ` Emil Velikov
2016-06-16 19:14     ` Emil Velikov
2016-06-29  4:31     ` Daniel Kurtz
2016-06-29  4:31       ` Daniel Kurtz
2016-06-29  4:31       ` Daniel Kurtz
2016-07-12 10:13       ` Daniel Vetter [this message]
2016-07-12 10:13         ` Daniel Vetter
2016-07-12 10:13         ` Daniel Vetter
2016-08-04 10:35         ` Enric Balletbo Serra
2016-08-04 10:35           ` Enric Balletbo Serra
2016-08-04 10:35           ` Enric Balletbo Serra
2016-08-04 10:58           ` Daniel Vetter
2016-08-04 10:58             ` Daniel Vetter
2016-08-04 10:58             ` Daniel Vetter
2016-08-04 12:23         ` Russell King - ARM Linux
2016-08-04 12:23           ` Russell King - ARM Linux
2016-08-04 12:23           ` Russell King - ARM Linux

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