linux-kernel - Re: [PATCH v3 1/3] drm/bridge: it6505: fix AUX read use aux fifo

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Message-ID: <wub2lb7eeswh4ztvyyofb7sajcqv6fkgzjuv7fmo22ykv5jj54@locn6d4mldjs>
Date: Mon, 23 Sep 2024 13:07:34 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Hermes Wu <Hermes.Wu@....com.tw>
Cc: Pin-yen Lin <treapking@...omium.org>, 
	Kenneth Hung <Kenneth.hung@....com.tw>, Andrzej Hajda <andrzej.hajda@...el.com>, 
	Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>, Jonas Karlman <jonas@...boo.se>, 
	Jernej Skrabec <jernej.skrabec@...il.com>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
	"open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/3] drm/bridge: it6505: fix AUX read use aux fifo

On Mon, Sep 23, 2024 at 05:48:26PM GMT, Hermes Wu wrote:
> From: Hermes Wu <Hermes.wu@....com.tw>
> 
> Changes in v3:
>  -New in v3
> 
> 
> it6505 AUX FIFO mode only 16 byte.
> AUX FIFO mode only supports EDID read and DPCD KSV FIFO area.

ENOTREADABLE. It should be a text, not a set of phrases.
Also changelog comes afterwards.

> 
> Signed-off-by: Hermes Wu <Hermes.wu@....com.tw>
> ---
>  drivers/gpu/drm/bridge/ite-it6505.c | 25 +++++++++++++++++--------
>  1 file changed, 17 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
> index 87b8545fccc0..d8b40ad890bf 100644
> --- a/drivers/gpu/drm/bridge/ite-it6505.c
> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
> @@ -300,7 +300,7 @@
>  #define MAX_CR_LEVEL 0x03
>  #define MAX_EQ_LEVEL 0x03
>  #define AUX_WAIT_TIMEOUT_MS 15
> -#define AUX_FIFO_MAX_SIZE 32
> +#define AUX_FIFO_MAX_SIZE 16
>  #define PIXEL_CLK_DELAY 1
>  #define PIXEL_CLK_INVERSE 0
>  #define ADJUST_PHASE_THRESHOLD 80000
> @@ -324,8 +324,13 @@ enum aux_cmd_type {
>  	CMD_AUX_NATIVE_READ = 0x0,
>  	CMD_AUX_NATIVE_WRITE = 0x5,
>  	CMD_AUX_I2C_EDID_READ = 0xB,
> +
> +	/* KSV list read using AUX native read with FIFO */
> +	CMD_AUX_GET_KSV_LIST = 0x10,

Don't mix two changes in a single patch. There should be one patch
fixing FIFO_MAX_SIDE (and then it should have Fixes tag) and another
patch adding CMD_AUX_GET_KSV_LIST. I keep on pointing to
Documenation/process/submitting-patches.rst, which you didn't seem to
have read. Please do it first. Ask any questions if you don't understand
something.

>  };
>  
> +#define GET_AUX_CONTROL_CODE(cmd) ((cmd) & 0x0F)
> +
>  enum aux_cmd_reply {
>  	REPLY_ACK,
>  	REPLY_NACK,
> @@ -965,7 +970,8 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
>  	it6505_set_bits(it6505, REG_AUX_CTRL, AUX_USER_MODE, AUX_USER_MODE);
>  
>  aux_op_start:
> -	if (cmd == CMD_AUX_I2C_EDID_READ) {
> +	/* HW AUX FIFO supports only EDID and DCPD KSV FIFO aread */
> +	if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
>  		/* AUX EDID FIFO has max length of AUX_FIFO_MAX_SIZE bytes. */
>  		size = min_t(size_t, size, AUX_FIFO_MAX_SIZE);
>  		/* Enable AUX FIFO read back and clear FIFO */
> @@ -996,7 +1002,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
>  				  size);
>  
>  	/* Aux Fire */
> -	it6505_write(it6505, REG_AUX_CMD_REQ, cmd);
> +	it6505_write(it6505, REG_AUX_CMD_REQ, GET_AUX_CONTROL_CODE(cmd));

Looks like a separate fix.

>  
>  	ret = it6505_aux_wait(it6505);
>  	if (ret < 0)
> @@ -1030,7 +1036,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
>  		goto aux_op_start;
>  	}
>  
> -	if (cmd == CMD_AUX_I2C_EDID_READ) {
> +	if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
>  		for (i = 0; i < size; i++) {
>  			ret = it6505_read(it6505, REG_AUX_DATA_FIFO);
>  			if (ret < 0)
> @@ -1055,7 +1061,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
>  	ret = i;
>  
>  aux_op_err:
> -	if (cmd == CMD_AUX_I2C_EDID_READ) {
> +	if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
>  		/* clear AUX FIFO */
>  		it6505_set_bits(it6505, REG_AUX_CTRL,
>  				AUX_EN_FIFO_READ | CLR_EDID_FIFO,
> @@ -1078,8 +1084,11 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
>  	int i, ret_size, ret = 0, request_size;
>  
>  	mutex_lock(&it6505->aux_lock);
> -	for (i = 0; i < size; i += 4) {
> -		request_size = min((int)size - i, 4);
> +	for (i = 0; i < size; ) {
> +		if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST)
> +			request_size = min_t(int, (int)size - i, AUX_FIFO_MAX_SIZE);
> +		else
> +			request_size = min_t(int, (int)size - i, 4);

And this one is also separate.

>  		ret_size = it6505_aux_operation(it6505, cmd, address + i,
>  						buffer + i, request_size,
>  						reply);
> @@ -1088,6 +1097,7 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
>  			goto aux_op_err;
>  		}
>  
> +		i += request_size;
>  		ret += ret_size;
>  	}
>  
> @@ -2257,7 +2267,6 @@ static void it6505_link_training_work(struct work_struct *work)
>  		it6505->auto_train_retry--;
>  		it6505_dump(it6505);
>  	}
> -

And this is just a noise. Leave it as it is until somebody has to touch
these lines.

>  }
>  
>  static void it6505_plugged_status_to_codec(struct it6505 *it6505)
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry