| Message ID | 20240515135411.343333-8-elinor.montmasson@savoirfairelinux.com |
|---|---|
| State | New |
| Headers | show |
| Series | [PATCHv4,1/9] ASoC: fsl-asoc-card: add support for dai links with multiple codecs | expand |
From: "Mark Brown" <broonie@kernel.org> Sent: Thursday, 16 May, 2024 14:13:19 > On Wed, May 15, 2024 at 03:54:09PM +0200, Elinor Montmasson wrote: > >> Add an optional DT clock "cpu_sysclk" to get the CPU DAI system-clock >> frequency when using the generic codec. >> It is set for both Tx and Rx. >> The way the frequency value is used is up to the CPU DAI driver >> implementation. > >> + struct clk *cpu_sysclk = clk_get(&pdev->dev, "cpu_sysclk"); >> + if (!IS_ERR(cpu_sysclk)) { >> + priv->cpu_priv.sysclk_freq[TX] = clk_get_rate(cpu_sysclk); >> + priv->cpu_priv.sysclk_freq[RX] = priv->cpu_priv.sysclk_freq[TX]; >> + clk_put(cpu_sysclk); >> + } > > I don't really understand the goal here - this is just reading whatever > frequency happens to be set in the hardware when the driver starts up > which if nothing else seems rather fragile? The driver allow to set the sysclk frequency of the CPU DAI through `priv->cpu_priv.sysclk_freq` when calling `fsl_asoc_card_hw_params()`. Currently it is hard-coded per use-case in the driver. My reasoning was that with a generic codec/compatible, there might be use-cases needing to use this parameter, so I exposed it here via DT. Is it a bad idea to expose this parameter ? This is not a requirement for the driver to work, most of the current compatibles do not use this parameter. It is currently used only for `fsl,imx-audio-cs42888`. In that case I can remove this commit. Best regards, Elinor Montmasson
On Fri, May 17, 2024 at 05:05:35AM -0400, Elinor Montmasson wrote: > From: "Mark Brown" <broonie@kernel.org> > > On Wed, May 15, 2024 at 03:54:09PM +0200, Elinor Montmasson wrote: > >> + struct clk *cpu_sysclk = clk_get(&pdev->dev, "cpu_sysclk"); > >> + if (!IS_ERR(cpu_sysclk)) { > >> + priv->cpu_priv.sysclk_freq[TX] = clk_get_rate(cpu_sysclk); > >> + priv->cpu_priv.sysclk_freq[RX] = priv->cpu_priv.sysclk_freq[TX]; > >> + clk_put(cpu_sysclk); > >> + } > > I don't really understand the goal here - this is just reading whatever > > frequency happens to be set in the hardware when the driver starts up > > which if nothing else seems rather fragile? > The driver allow to set the sysclk frequency > of the CPU DAI through `priv->cpu_priv.sysclk_freq` when calling > `fsl_asoc_card_hw_params()`. > Currently it is hard-coded per use-case in the driver. > My reasoning was that with a generic codec/compatible, there might > be use-cases needing to use this parameter, so I exposed it here via DT. > Is it a bad idea to expose this parameter ? This is not a requirement for the > driver to work, most of the current compatibles do not use this parameter. > It is currently used only for `fsl,imx-audio-cs42888`. > In that case I can remove this commit. I'm having a hard time connecting your reply here with my comment. This isn't as far as I can see allowing the frequency to be explicitly configured, it's just using whatever value happens to be programmed in the clock when the driver starts.
From: "Mark Brown" <broonie@kernel.org> Sent: Friday, 17 May, 2024 13:17:20 > On Fri, May 17, 2024 at 05:05:35AM -0400, Elinor Montmasson wrote: >> From: "Mark Brown" <broonie@kernel.org> >> > On Wed, May 15, 2024 at 03:54:09PM +0200, Elinor Montmasson wrote: > >> >> + struct clk *cpu_sysclk = clk_get(&pdev->dev, "cpu_sysclk"); >> >> + if (!IS_ERR(cpu_sysclk)) { >> >> + priv->cpu_priv.sysclk_freq[TX] = clk_get_rate(cpu_sysclk); >> >> + priv->cpu_priv.sysclk_freq[RX] = priv->cpu_priv.sysclk_freq[TX]; >> >> + clk_put(cpu_sysclk); >> >> + } > >> > I don't really understand the goal here - this is just reading whatever >> > frequency happens to be set in the hardware when the driver starts up >> > which if nothing else seems rather fragile? > >> The driver allow to set the sysclk frequency >> of the CPU DAI through `priv->cpu_priv.sysclk_freq` when calling >> `fsl_asoc_card_hw_params()`. >> Currently it is hard-coded per use-case in the driver. > >> My reasoning was that with a generic codec/compatible, there might >> be use-cases needing to use this parameter, so I exposed it here via DT. > >> Is it a bad idea to expose this parameter ? This is not a requirement for the >> driver to work, most of the current compatibles do not use this parameter. >> It is currently used only for `fsl,imx-audio-cs42888`. >> In that case I can remove this commit. > > I'm having a hard time connecting your reply here with my comment. This > isn't as far as I can see allowing the frequency to be explicitly > configured, it's just using whatever value happens to be programmed in > the clock when the driver starts. In v3 I used parameters `cpu-sysclk-freq-rx/tx` to explicitly set the frequency. In its review Rob Herring said that the clock bindings should be used, so that's why I changed it to use this `cpu_sysclk` clock.
On Fri, May 31, 2024 at 08:46:55AM -0400, Elinor Montmasson wrote: > From: "Mark Brown" <broonie@kernel.org> > > On Fri, May 17, 2024 at 05:05:35AM -0400, Elinor Montmasson wrote: > >> From: "Mark Brown" <broonie@kernel.org> > >> > On Wed, May 15, 2024 at 03:54:09PM +0200, Elinor Montmasson wrote: > >> >> + struct clk *cpu_sysclk = clk_get(&pdev->dev, "cpu_sysclk"); > >> >> + if (!IS_ERR(cpu_sysclk)) { > >> >> + priv->cpu_priv.sysclk_freq[TX] = clk_get_rate(cpu_sysclk); > >> >> + priv->cpu_priv.sysclk_freq[RX] = priv->cpu_priv.sysclk_freq[TX]; > >> >> + clk_put(cpu_sysclk); > >> >> + } > >> > I don't really understand the goal here - this is just reading whatever > >> > frequency happens to be set in the hardware when the driver starts up > >> > which if nothing else seems rather fragile? > >> The driver allow to set the sysclk frequency > >> of the CPU DAI through `priv->cpu_priv.sysclk_freq` when calling > >> `fsl_asoc_card_hw_params()`. > >> Currently it is hard-coded per use-case in the driver. > >> My reasoning was that with a generic codec/compatible, there might > >> be use-cases needing to use this parameter, so I exposed it here via DT. > > > >> Is it a bad idea to expose this parameter ? This is not a requirement for the > >> driver to work, most of the current compatibles do not use this parameter. > >> It is currently used only for `fsl,imx-audio-cs42888`. > >> In that case I can remove this commit. > > I'm having a hard time connecting your reply here with my comment. This > > isn't as far as I can see allowing the frequency to be explicitly > > configured, it's just using whatever value happens to be programmed in > > the clock when the driver starts. > In v3 I used parameters `cpu-sysclk-freq-rx/tx` to explicitly > set the frequency. > In its review Rob Herring said that the clock bindings should > be used, so that's why I changed it to use this `cpu_sysclk` clock. So you're trying to use this as the audio clock? There's no code that enables the clock which seems worrying, and I'd expect that if the device is using it's own clock the device would be querying it directly via the clock API rather than this. This all seems really confused.
On Fri, May 31, 2024 at 10:48:12AM -0400, Elinor Montmasson wrote: > From: "Mark Brown" <broonie@kernel.org> > > So you're trying to use this as the audio clock? There's no code that > > enables the clock which seems worrying, and I'd expect that if the > > device is using it's own clock the device would be querying it directly > > via the clock API rather than this. This all seems really confused. > It's not specifically the audio clock, I am merely using this > in the machine driver to let the user the possibility > to configure the CPU DAI sysclock frequency. > The CPU DAI and codec drivers already manage their > own clocks. I would expect that if the clocks used by the devices are configured via the clock API then the drivers for those devices will configure themselves via the clock API. I still don't understand what this change is intended to accomplish.
diff --git a/sound/soc/fsl/fsl-asoc-card.c b/sound/soc/fsl/fsl-asoc-card.c index 9aca8ad15372..c7fc9c16f761 100644 --- a/sound/soc/fsl/fsl-asoc-card.c +++ b/sound/soc/fsl/fsl-asoc-card.c @@ -754,6 +754,12 @@ static int fsl_asoc_card_probe(struct platform_device *pdev) snd_soc_of_parse_tdm_slot(np, NULL, NULL, &priv->cpu_priv.slot_num, &priv->cpu_priv.slot_width); + struct clk *cpu_sysclk = clk_get(&pdev->dev, "cpu_sysclk"); + if (!IS_ERR(cpu_sysclk)) { + priv->cpu_priv.sysclk_freq[TX] = clk_get_rate(cpu_sysclk); + priv->cpu_priv.sysclk_freq[RX] = priv->cpu_priv.sysclk_freq[TX]; + clk_put(cpu_sysclk); + } } else { dev_err(&pdev->dev, "unknown Device Tree compatible\n"); ret = -EINVAL;
Add an optional DT clock "cpu_sysclk" to get the CPU DAI system-clock frequency when using the generic codec. It is set for both Tx and Rx. The way the frequency value is used is up to the CPU DAI driver implementation. Signed-off-by: Elinor Montmasson <elinor.montmasson@savoirfairelinux.com> --- sound/soc/fsl/fsl-asoc-card.c | 6 ++++++ 1 file changed, 6 insertions(+)