linux-kernel - Re: [PATCH v2 3/7] media: i2c: max9286: Break-out reverse channel setup

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Message-ID: <c11390aa-c3af-8cad-141e-2cee7909ae97@ideasonboard.com>
Date:   Thu, 15 Oct 2020 20:53:24 +0100
From:   Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
To:     Jacopo Mondi <jacopo+renesas@...ndi.org>,
        laurent.pinchart+renesas@...asonboard.com,
        niklas.soderlund+renesas@...natech.se
Cc:     linux-media@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org, Hyun Kwon <hyunk@...inx.com>,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Subject: Re: [PATCH v2 3/7] media: i2c: max9286: Break-out reverse channel
 setup

Hi Jacopo,

On 15/10/2020 19:27, Jacopo Mondi wrote:
> Break out the reverse channel setup configuration procedure to its own
> function.
> 
> This change prepares for configuring the reverse channel conditionally
> to the remote side high threshold configuration.
> 
> No functional changes intended.
> 
> Signed-off-by: Jacopo Mondi <jacopo+renesas@...ndi.org>
> ---
>  drivers/media/i2c/max9286.c | 30 +++++++++++++++++-------------
>  1 file changed, 17 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> index d969ac21a058..89a7248f5c25 100644
> --- a/drivers/media/i2c/max9286.c
> +++ b/drivers/media/i2c/max9286.c
> @@ -906,6 +906,22 @@ static void max9286_v4l2_unregister(struct max9286_priv *priv)
>   * Probe/Remove
>   */
>  
> +static void max9286_reverse_channel_setup(struct max9286_priv *priv)
> +{
> +	/*
> +	 * Reverse channel setup.
> +	 *
> +	 * - Enable custom reverse channel configuration (through register 0x3f)
> +	 *   and set the first pulse length to 35 clock cycles.
> +	 * - Increase the reverse channel amplitude to 170mV to accommodate the
> +	 *   high threshold enabled by the serializer driver.
> +	 */
> +	max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35));
> +	max9286_write(priv, 0x3b, MAX9286_REV_TRF(1) | MAX9286_REV_AMP(70) |
> +		      MAX9286_REV_AMP_X);
> +	usleep_range(2000, 2500);
> +}

This gets moved later on in the same series. It's probably better to put
it in the right place now.

With that,

Reviewed-by: Kieran Bingham <kieran.bingham+renesasa@...asonboard.com>

> +
>  static int max9286_setup(struct max9286_priv *priv)
>  {
>  	/*
> @@ -941,19 +957,7 @@ static int max9286_setup(struct max9286_priv *priv)
>  	 * only. This should be disabled after the mux is initialised.
>  	 */
>  	max9286_configure_i2c(priv, true);
> -
> -	/*
> -	 * Reverse channel setup.
> -	 *
> -	 * - Enable custom reverse channel configuration (through register 0x3f)
> -	 *   and set the first pulse length to 35 clock cycles.
> -	 * - Increase the reverse channel amplitude to 170mV to accommodate the
> -	 *   high threshold enabled by the serializer driver.
> -	 */
> -	max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35));
> -	max9286_write(priv, 0x3b, MAX9286_REV_TRF(1) | MAX9286_REV_AMP(70) |
> -		      MAX9286_REV_AMP_X);
> -	usleep_range(2000, 2500);
> +	max9286_reverse_channel_setup(priv);
>  
>  	/*
>  	 * Enable GMSL links, mask unused ones and autodetect link
>