linux-kernel - Re: [PATCH v5] ASoC: cros_ec_codec: Reset I2S RX when probing

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Message-ID: <d5a36f72-82a1-450c-3763-a27df31b8da4@collabora.com>
Date:   Wed, 13 Jan 2021 10:03:16 +0100
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Yu-Hsuan Hsu <yuhsuan@...omium.org>, linux-kernel@...r.kernel.org
Cc:     Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        Cheng-Yi Chiang <cychiang@...omium.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Prashant Malani <pmalani@...omium.org>,
        Pi-Hsun Shih <pihsun@...omium.org>,
        "Gustavo A . R . Silva" <gustavoars@...nel.org>,
        alsa-devel@...a-project.org
Subject: Re: [PATCH v5] ASoC: cros_ec_codec: Reset I2S RX when probing

Hi Yu-Hsun,

Thank you for your patch. Some comments below.


On 13/1/21 9:17, Yu-Hsuan Hsu wrote:
> It is not guaranteed that I2S RX is disabled when the kernel booting.
> For example, if the kernel crashes while it is enabled, it will keep
> enabled until the next time EC reboots. Reset I2S RX when probing to
> fix this issue.
> 
> Signed-off-by: Yu-Hsuan Hsu <yuhsuan@...omium.org>
> ---
> This patch checks the return value. If it is -ENOPROTOOPT
> (EC_RES_INVALID_VERSION), it will ask clients to update EC firmware.
> 
> Previous patches
> 
> v1: https://patchwork.kernel.org/project/alsa-devel/patch/20200708071117.3070707-1-yuhsuan@chromium.org/
> 
> v2: https://patchwork.kernel.org/project/alsa-devel/patch/20200716170914.3623060-1-yuhsuan@chromium.org/
> 
> v3: https://patchwork.kernel.org/project/alsa-devel/patch/20210106050559.1459027-1-yuhsuan@chromium.org/
> 
> v4: https://patchwork.kernel.org/project/alsa-devel/patch/20210107085942.2891525-2-yuhsuan@chromium.org/
> 
>  include/linux/platform_data/cros_ec_commands.h |  1 +

Sorry if I confused you with my last comments, but this should be a separate patch.

>  sound/soc/codecs/cros_ec_codec.c               | 11 +++++++++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/include/linux/platform_data/cros_ec_commands.h b/include/linux/platform_data/cros_ec_commands.h
> index 86376779ab31..95889ada83a3 100644
> --- a/include/linux/platform_data/cros_ec_commands.h
> +++ b/include/linux/platform_data/cros_ec_commands.h
> @@ -4600,6 +4600,7 @@ enum ec_codec_i2s_rx_subcmd {
>  	EC_CODEC_I2S_RX_SET_SAMPLE_DEPTH = 0x2,
>  	EC_CODEC_I2S_RX_SET_DAIFMT = 0x3,
>  	EC_CODEC_I2S_RX_SET_BCLK = 0x4,
> +	EC_CODEC_I2S_RX_RESET = 0x5,
>  	EC_CODEC_I2S_RX_SUBCMD_COUNT,
>  };
>  
> diff --git a/sound/soc/codecs/cros_ec_codec.c b/sound/soc/codecs/cros_ec_codec.c
> index f33a2a9654e7..d35c57724b45 100644
> --- a/sound/soc/codecs/cros_ec_codec.c
> +++ b/sound/soc/codecs/cros_ec_codec.c
> @@ -1011,6 +1011,17 @@ static int cros_ec_codec_platform_probe(struct platform_device *pdev)
>  	}
>  	priv->ec_capabilities = r.capabilities;
>  
> +	/* Reset EC codec i2s rx. */
> +	p.cmd = EC_CODEC_I2S_RX_RESET;
> +	ret = send_ec_host_command(priv->ec_device, EC_CMD_EC_CODEC_I2S_RX,
> +				   (uint8_t *)&p, sizeof(p), NULL, 0);
> +	if (ret == -ENOPROTOOPT) {
> +		dev_info(dev,
> +			 "Command not found. Please update the EC firmware.\n");
> +	} else if (ret) {
> +		dev_err(dev, "failed to EC_CODEC_I2S_RESET: %d\n", ret);

On an error you should return the error and don't continue.

Thanks,
  Enric

> +	}
> +
>  	platform_set_drvdata(pdev, priv);
>  
>  	ret = devm_snd_soc_register_component(dev, &i2s_rx_component_driver,
>