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From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Alex Riesen <alexander.riesen@cetitec.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	Kieran Bingham <kieran.bingham@ideasonboard.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Driver Development <devel@driverdev.osuosl.org>,
	Linux Media <linux-media@vger.kernel.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Device Tree <devicetree@vger.kernel.org>,
	Renesas SoC <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH 8/8] arm64: dts: renesas: salvator: add a connection from adv748x codec (HDMI input) to the R-Car SoC
Date: Fri, 6 Mar 2020 15:16:32 +0200	[thread overview]
Message-ID: <20200306131632.GA4878@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20200305143628.GB25741@pflmari>

Hi Alex,

On Thu, Mar 05, 2020 at 03:36:28PM +0100, Alex Riesen wrote:
> Geert Uytterhoeven, Mon, Mar 02, 2020 17:13:30 +0100:
> > On Mon, Mar 2, 2020 at 5:09 PM Alex Riesen <alexander.riesen@cetitec.com> wrote:
> > > Geert Uytterhoeven, Mon, Mar 02, 2020 16:32:32 +0100:
> > > >
> > > > The #clock-cells should be in the main video-receiver node.
> > > > Probably there is more than one clock output, so #clock-cells may be 1?
> > >
> > > AFAICS, the device can provide only this one clock line (audio master clock
> > > for I2S output)... I shall re-check, just in case.
> 
> And you're right, of course: the audio output formatting module of the ADV748x
> devices provides a set of clock lines related to the I2S pins: the already
> discussed master clock, left-right channel clock and the serial clock (bit
> clock?).

I don't think we need to model the last two clocks through CCF though,
they're part of the I2S protocol, not clock sources that need to be
explicitly controlled (or queried).

> > > > There is no need for a fixed-clock compatible, nor for clock-frequency
> > > > and clock-output-names.
> > > >
> > > > But most important: this should be documented in the adv748x DT bindings,
> > > > and implemented in the adv748x driver.
> > >
> > > So if the driver is to export that clock for the kernel (like in this case),
> > > it must implement its support?
> > 
> > Exactly.  Unless that pin is hardcoded to output a fixed clock, in which case
> > you can just override the existing audio_clk_c rate.
> 
> Just to try it out (I'll set #clock-cells to 1), I registered a fixed rate
> clock in the driver, added a clock provider:
> 
> adv748x_probe:
> 
>     clk = clk_register_fixed_rate(state->dev,
> 				  "clk-hdmi-i2s-mclk",
> 				  NULL     /* parent_name */,
> 				  0        /* flags */,
> 				  12288000 /* rate */);
>     of_clk_add_provider(state->dev->of_node, of_clk_src_simple_get, clk);
> 
> And removed the audio_clk_c frequency setting. I also replaced the audio_clk_c
> in the list of input clocks of the R-Car-side sound card with the phandle of
> the adv7482 main node:
> 
> salvator-common.dtsi:
> 
>     &i2c4 {
> 	status = "okay";
> 
> 	adv7482_hdmi_decoder: video-receiver@70 {
> 	    #clock-cells = <0>; // to be replaced with <1>
> 	};
>     };
> 
>     &rcar_sound {
> 	clocks = ..., <&adv7482_hdmi_decoder>, ...;
>     };
> 
> As everything continues to work as before, I assume that at least the clock
> dependencies were resolved.

This looks good to me.

> Is there a way to verify that the added input clock is actually used?
> IOW, if its frequency is actually has been programmed into the ssi4 (R-Car
> receiving hardware) registers, and not just a left-over from previuos attempts
> or plain default setting?
> 
> As the ADV748x devices seem to provide also the clocks for video outputs, will
> it make any sense to place the clock definition into the port node?
> Or should all provided clocks be indexed in the main device node?

Those clocks are part of the CSI-2 protocol and also don't need to be
explicitly controlled. As far as I can tell from a quick check of the
ADV7482 documentation, only the I2S MCLK is a general-purpose clock that
needs to be exposed.

-- 
Regards,

Laurent Pinchart

WARNING: multiple messages have this Message-ID
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Alex Riesen <alexander.riesen@cetitec.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Driver Development <devel@driverdev.osuosl.org>,
	Device Tree <devicetree@vger.kernel.org>,
	Kieran Bingham <kieran.bingham@ideasonboard.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Renesas SoC <linux-renesas-soc@vger.kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Linux Media <linux-media@vger.kernel.org>
Subject: Re: [PATCH 8/8] arm64: dts: renesas: salvator: add a connection from adv748x codec (HDMI input) to the R-Car SoC
Date: Fri, 6 Mar 2020 15:16:32 +0200	[thread overview]
Message-ID: <20200306131632.GA4878@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20200305143628.GB25741@pflmari>

Hi Alex,

On Thu, Mar 05, 2020 at 03:36:28PM +0100, Alex Riesen wrote:
> Geert Uytterhoeven, Mon, Mar 02, 2020 17:13:30 +0100:
> > On Mon, Mar 2, 2020 at 5:09 PM Alex Riesen <alexander.riesen@cetitec.com> wrote:
> > > Geert Uytterhoeven, Mon, Mar 02, 2020 16:32:32 +0100:
> > > >
> > > > The #clock-cells should be in the main video-receiver node.
> > > > Probably there is more than one clock output, so #clock-cells may be 1?
> > >
> > > AFAICS, the device can provide only this one clock line (audio master clock
> > > for I2S output)... I shall re-check, just in case.
> 
> And you're right, of course: the audio output formatting module of the ADV748x
> devices provides a set of clock lines related to the I2S pins: the already
> discussed master clock, left-right channel clock and the serial clock (bit
> clock?).

I don't think we need to model the last two clocks through CCF though,
they're part of the I2S protocol, not clock sources that need to be
explicitly controlled (or queried).

> > > > There is no need for a fixed-clock compatible, nor for clock-frequency
> > > > and clock-output-names.
> > > >
> > > > But most important: this should be documented in the adv748x DT bindings,
> > > > and implemented in the adv748x driver.
> > >
> > > So if the driver is to export that clock for the kernel (like in this case),
> > > it must implement its support?
> > 
> > Exactly.  Unless that pin is hardcoded to output a fixed clock, in which case
> > you can just override the existing audio_clk_c rate.
> 
> Just to try it out (I'll set #clock-cells to 1), I registered a fixed rate
> clock in the driver, added a clock provider:
> 
> adv748x_probe:
> 
>     clk = clk_register_fixed_rate(state->dev,
> 				  "clk-hdmi-i2s-mclk",
> 				  NULL     /* parent_name */,
> 				  0        /* flags */,
> 				  12288000 /* rate */);
>     of_clk_add_provider(state->dev->of_node, of_clk_src_simple_get, clk);
> 
> And removed the audio_clk_c frequency setting. I also replaced the audio_clk_c
> in the list of input clocks of the R-Car-side sound card with the phandle of
> the adv7482 main node:
> 
> salvator-common.dtsi:
> 
>     &i2c4 {
> 	status = "okay";
> 
> 	adv7482_hdmi_decoder: video-receiver@70 {
> 	    #clock-cells = <0>; // to be replaced with <1>
> 	};
>     };
> 
>     &rcar_sound {
> 	clocks = ..., <&adv7482_hdmi_decoder>, ...;
>     };
> 
> As everything continues to work as before, I assume that at least the clock
> dependencies were resolved.

This looks good to me.

> Is there a way to verify that the added input clock is actually used?
> IOW, if its frequency is actually has been programmed into the ssi4 (R-Car
> receiving hardware) registers, and not just a left-over from previuos attempts
> or plain default setting?
> 
> As the ADV748x devices seem to provide also the clocks for video outputs, will
> it make any sense to place the clock definition into the port node?
> Or should all provided clocks be indexed in the main device node?

Those clocks are part of the CSI-2 protocol and also don't need to be
explicitly controlled. As far as I can tell from a quick check of the
ADV7482 documentation, only the I2S MCLK is a general-purpose clock that
needs to be exposed.

-- 
Regards,

Laurent Pinchart
_______________________________________________
devel mailing list
devel@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel

  parent reply	other threads:[~2020-03-06 13:16 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-13 14:19 [PATCH 0/8] media: i2c: adv748x: add support for HDMI audio Alex Riesen
2020-01-13 14:19 ` Alex Riesen
2020-01-13 14:15 ` [PATCH 1/8] media: adv748x: add a device-specific wrapper for register block read Alex Riesen
2020-01-13 14:15   ` Alex Riesen
2020-01-13 14:15 ` [PATCH 2/8] media: adv748x: add audio mute control and output selection ioctls Alex Riesen
2020-01-13 14:15   ` Alex Riesen
2020-03-13  8:16   ` Hans Verkuil
2020-03-13  8:16     ` Hans Verkuil
2020-03-13 10:26     ` Alex Riesen
2020-03-13 10:26       ` Alex Riesen
2020-03-13 10:52       ` Hans Verkuil
2020-03-13 10:52         ` Hans Verkuil
2020-03-13 11:00         ` Alex Riesen
2020-03-13 11:00           ` Alex Riesen
2020-01-13 14:15 ` [PATCH 3/8] media: adv748x: add log_status ioctl Alex Riesen
2020-01-13 14:15   ` Alex Riesen
2020-01-13 14:15 ` [PATCH 4/8] media: adv748x: reserve space for the audio (I2S) port in the driver structures Alex Riesen
2020-01-13 14:15   ` Alex Riesen
2020-01-13 14:15 ` [PATCH 5/8] media: adv748x: add an ASoC DAI definition to the driver Alex Riesen
2020-01-13 14:15   ` Alex Riesen
2020-01-13 14:15 ` [PATCH 6/8] media: adv748x: reduce amount of code for bitwise modification of device registers Alex Riesen
2020-01-13 14:15   ` Alex Riesen
2020-01-13 14:15 ` [PATCH 7/8] dt-bindings: adv748x: add information about serial audio interface (I2S/TDM) Alex Riesen
2020-01-13 14:15   ` Alex Riesen
2020-01-13 22:32   ` Rob Herring
2020-01-13 22:32     ` Rob Herring
2020-01-13 14:15 ` [PATCH 8/8] arm64: dts: renesas: salvator: add a connection from adv748x codec (HDMI input) to the R-Car SoC Alex Riesen
2020-01-13 14:15   ` Alex Riesen
2020-03-02 12:28   ` Geert Uytterhoeven
2020-03-02 12:28     ` Geert Uytterhoeven
2020-03-02 13:40     ` Alex Riesen
2020-03-02 13:40       ` Alex Riesen
2020-03-02 13:47       ` Geert Uytterhoeven
2020-03-02 13:47         ` Geert Uytterhoeven
2020-03-02 15:07         ` Alex Riesen
2020-03-02 15:07           ` Alex Riesen
2020-03-02 15:32           ` Geert Uytterhoeven
2020-03-02 15:32             ` Geert Uytterhoeven
2020-03-02 16:09             ` Alex Riesen
2020-03-02 16:09               ` Alex Riesen
2020-03-02 16:13               ` Geert Uytterhoeven
2020-03-02 16:13                 ` Geert Uytterhoeven
2020-03-05 14:36                 ` Alex Riesen
2020-03-05 14:36                   ` Alex Riesen
2020-03-06 12:21                   ` Geert Uytterhoeven
2020-03-06 12:21                     ` Geert Uytterhoeven
2020-03-06 13:16                   ` Laurent Pinchart [this message]
2020-03-06 13:16                     ` Laurent Pinchart
2020-03-06 13:41                     ` Alex Riesen
2020-03-06 13:41                       ` Alex Riesen
2020-03-06 13:45                       ` Laurent Pinchart
2020-03-06 13:45                         ` Laurent Pinchart
2020-03-09  1:31                         ` Kuninori Morimoto
2020-03-09  1:31                           ` Kuninori Morimoto
2020-03-09 11:09                           ` Alex Riesen
2020-03-09 11:09                             ` Alex Riesen
2020-03-10  1:07                             ` Kuninori Morimoto
2020-03-10  1:07                               ` Kuninori Morimoto
2020-03-10  8:17                               ` Alex Riesen
2020-03-10  8:17                                 ` Alex Riesen
2020-03-10 10:39                                 ` Laurent Pinchart
2020-03-10 10:39                                   ` Laurent Pinchart

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