Re: [PATCH v3 1/8] Input: atmel_mxt_ts - add support for T37 diagnostic data

[Dmitry Torokhov]

Hi Nick,

On Wed, Jun 01, 2016 at 05:39:45PM +0100, Nick Dyer wrote:
> Atmel maXTouch devices have a T37 object which can be used to read raw
> touch deltas from the device. This consists of an array of 16-bit
> integers, one for each node on the touchscreen matrix.
> 
> Signed-off-by: Nick Dyer <nick.dyer@xxxxxxxxxxx>
> ---
>  drivers/input/touchscreen/atmel_mxt_ts.c | 152 +++++++++++++++++++++++++++++++
>  1 file changed, 152 insertions(+)
> 
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 5af7907..21f42ed 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -124,6 +124,17 @@ struct t9_range {
>  #define MXT_COMMS_CTRL		0
>  #define MXT_COMMS_CMD		1
>  
> +/* MXT_DEBUG_DIAGNOSTIC_T37 */
> +#define MXT_DIAGNOSTIC_PAGEUP	0x01
> +#define MXT_DIAGNOSTIC_DELTAS	0x10
> +#define MXT_DIAGNOSTIC_SIZE	128
> +
> +struct t37_debug {
> +	u8 mode;
> +	u8 page;
> +	u8 data[MXT_DIAGNOSTIC_SIZE];
> +};
> +
>  /* Define for MXT_GEN_COMMAND_T6 */
>  #define MXT_BOOT_VALUE		0xa5
>  #define MXT_RESET_VALUE		0x01
> @@ -205,6 +216,14 @@ struct mxt_object {
>  	u8 num_report_ids;
>  } __packed;
>  
> +struct mxt_dbg {
> +	u16 t37_address;
> +	u16 diag_cmd_address;
> +	struct t37_debug *t37_buf;
> +	unsigned int t37_pages;
> +	unsigned int t37_nodes;
> +};
> +
>  /* Each client has this additional data */
>  struct mxt_data {
>  	struct i2c_client *client;
> @@ -233,6 +252,7 @@ struct mxt_data {
>  	u8 num_touchids;
>  	u8 multitouch;
>  	struct t7_config t7_cfg;
> +	struct mxt_dbg dbg;
>  
>  	/* Cached parameters from object table */
>  	u16 T5_address;
> @@ -2043,6 +2063,136 @@ recheck:
>  	return 0;
>  }
>  
> +static u16 mxt_get_debug_value(struct mxt_data *data, unsigned int x,
> +			       unsigned int y)
> +{
> +	struct mxt_dbg *dbg = &data->dbg;
> +	unsigned int ofs, page;
> +
> +	ofs = (y + (x * data->info.matrix_ysize)) * sizeof(u16);
> +	page = ofs / MXT_DIAGNOSTIC_SIZE;
> +	ofs %= MXT_DIAGNOSTIC_SIZE;
> +
> +	return get_unaligned_le16(&dbg->t37_buf[page].data[ofs]);
> +}
> +
> +static int mxt_convert_debug_pages(struct mxt_data *data, u16 *outbuf)
> +{
> +	struct mxt_dbg *dbg = &data->dbg;
> +	unsigned int x = 0;
> +	unsigned int y = 0;
> +	unsigned int i;
> +
> +	for (i = 0; i < dbg->t37_nodes; i++) {
> +		outbuf[i] = mxt_get_debug_value(data, x, y);
> +
> +		/* Next value */
> +		if (++x >= data->info.matrix_xsize) {
> +			x = 0;
> +			y++;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int mxt_read_diagnostic_debug(struct mxt_data *data, u8 mode,
> +				     u16 *outbuf)
> +{
> +	struct mxt_dbg *dbg = &data->dbg;
> +	int retries = 0;
> +	int page;
> +	int ret;
> +	u8 cmd = mode;
> +	struct t37_debug *p;
> +	u8 cmd_poll;
> +
> +	for (page = 0; page < dbg->t37_pages; page++) {
> +		p = dbg->t37_buf + page;
> +
> +		ret = mxt_write_reg(data->client, dbg->diag_cmd_address,
> +				    cmd);
> +		if (ret)
> +			return ret;
> +
> +		retries = 0;
> +		msleep(20);
> +wait_cmd:
> +		/* Read back command byte */
> +		ret = __mxt_read_reg(data->client, dbg->diag_cmd_address,
> +				     sizeof(cmd_poll), &cmd_poll);
> +		if (ret)
> +			return ret;
> +
> +		/* Field is cleared once the command has been processed */
> +		if (cmd_poll) {
> +			if (retries++ > 100)
> +				return -EINVAL;
> +
> +			msleep(20);
> +			goto wait_cmd;
> +		}
> +
> +		/* Read T37 page */
> +		ret = __mxt_read_reg(data->client, dbg->t37_address,
> +				sizeof(struct t37_debug), p);
> +		if (ret)
> +			return ret;
> +
> +		if ((p->mode != mode) || (p->page != page)) {

No need for extra parenthesis.

> +			dev_err(&data->client->dev, "T37 page mismatch\n");
> +			return -EINVAL;
> +		}
> +
> +		dev_dbg(&data->client->dev, "%s page:%d retries:%d\n",
> +			__func__, page, retries);
> +
> +		/* For remaining pages, write PAGEUP rather than mode */
> +		cmd = MXT_DIAGNOSTIC_PAGEUP;
> +	}
> +
> +	return mxt_convert_debug_pages(data, outbuf);
> +}
> +
> +static void mxt_debug_init(struct mxt_data *data)
> +{
> +	struct mxt_dbg *dbg = &data->dbg;
> +	struct mxt_object *object;
> +
> +	object = mxt_get_object(data, MXT_GEN_COMMAND_T6);
> +	if (!object)
> +		return;
> +
> +	dbg->diag_cmd_address = object->start_address + MXT_COMMAND_DIAGNOSTIC;
> +
> +	object = mxt_get_object(data, MXT_DEBUG_DIAGNOSTIC_T37);
> +	if (!object)
> +		return;
> +
> +	if (mxt_obj_size(object) != sizeof(struct t37_debug)) {
> +		dev_warn(&data->client->dev, "Bad T37 size");
> +		return;
> +	}
> +
> +	dbg->t37_address = object->start_address;
> +
> +	/* Calculate size of data and allocate buffer */
> +	dbg->t37_nodes = data->info.matrix_xsize * data->info.matrix_ysize;
> +	dbg->t37_pages = dbg->t37_nodes * sizeof(u16)
> +					/ sizeof(dbg->t37_buf->data) + 1;
> +
> +	dbg->t37_buf = devm_kzalloc(&data->client->dev,
> +				     sizeof(struct t37_debug) * dbg->t37_pages,
> +				     GFP_KERNEL);

devm_kcalloc() or devm_kmalloc_array() if memory does not need to be
zeroed out.

> +	if (!dbg->t37_buf)
> +		goto error;
> +
> +	return;
> +
> +error:
> +	dev_err(&data->client->dev, "Error initialising T37 diagnostic data\n");

Why do we only emit this message if memory allocation fails? And if it
is intentional why don't we do it inline?

> +}
> +
>  static int mxt_configure_objects(struct mxt_data *data,
>  				 const struct firmware *cfg)
>  {
> @@ -2070,6 +2220,8 @@ static int mxt_configure_objects(struct mxt_data *data,
>  		dev_warn(dev, "No touch object detected\n");
>  	}
>  
> +	mxt_debug_init(data);
> +
>  	dev_info(dev,
>  		 "Family: %u Variant: %u Firmware V%u.%u.%02X Objects: %u\n",
>  		 info->family_id, info->variant_id, info->version >> 4,
> -- 
> 2.5.0
> 

Thanks.

-- 
Dmitry