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Commit c3f78043 authored by Nick Dyer's avatar Nick Dyer Committed by Dmitry Torokhov
Browse files

Input: atmel_mxt_ts - implement CRC check for configuration data 



The configuration is stored in NVRAM on the maXTouch chip. When the device
is reset it reports a CRC of the stored configuration values. Therefore it
isn't necessary to send the configuration on each probe - we can check the
CRC matches and avoid a timeconsuming backup/reset cycle.

Signed-off-by: default avatarNick Dyer <nick.dyer@itdev.co.uk>
Acked-by: default avatarBenson Leung <bleung@chromium.org>
Acked-by: default avatarYufeng Shen <miletus@chromium.org>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 7bed6805

drivers/input/touchscreen/atmel_mxt_ts.c

+52 −8
Original line number Original line Diff line number Diff line
@@ -188,6 +188,7 @@ 
#define MXT_BACKUP_TIME		50	/* msec */

#define MXT_BACKUP_TIME		50	/* msec */

#define MXT_RESET_TIME		200	/* msec */

#define MXT_RESET_TIME		200	/* msec */

#define MXT_RESET_TIMEOUT	3000	/* msec */

#define MXT_RESET_TIMEOUT	3000	/* msec */

#define MXT_CRC_TIMEOUT		1000	/* msec */

#define MXT_FW_RESET_TIME	3000	/* msec */

#define MXT_FW_RESET_TIME	3000	/* msec */

#define MXT_FW_CHG_TIMEOUT	300	/* msec */

#define MXT_FW_CHG_TIMEOUT	300	/* msec */
@@ -259,6 +260,7 @@ struct mxt_data { 
	unsigned int max_x;

	unsigned int max_x;

	unsigned int max_y;

	unsigned int max_y;

	bool in_bootloader;

	bool in_bootloader;

	u32 config_crc;





	/* Cached parameters from object table */

	/* Cached parameters from object table */

	u8 T6_reportid;

	u8 T6_reportid;
@@ -272,6 +274,9 @@ struct mxt_data { 




	/* for reset handling */

	/* for reset handling */

	struct completion reset_completion;

	struct completion reset_completion;



	/* for config update handling */

	struct completion crc_completion;

};

};





static size_t mxt_obj_size(const struct mxt_object *obj)

static size_t mxt_obj_size(const struct mxt_object *obj)
@@ -636,7 +641,7 @@ static void mxt_input_touchevent(struct mxt_data *data, 
	}

	}

}

}





static unsigned mxt_extract_T6_csum(const u8 *csum)

static u16 mxt_extract_T6_csum(const u8 *csum)

{

{

	return csum[0] | (csum[1] << 8) | (csum[2] << 16);

	return csum[0] | (csum[1] << 8) | (csum[2] << 16);

}

}
@@ -654,6 +659,7 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data) 
	struct device *dev = &data->client->dev;

	struct device *dev = &data->client->dev;

	u8 reportid;

	u8 reportid;

	bool update_input = false;

	bool update_input = false;

	u32 crc;





	do {

	do {

		if (mxt_read_message(data, &message)) {

		if (mxt_read_message(data, &message)) {
@@ -665,9 +671,15 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data) 




		if (reportid == data->T6_reportid) {

		if (reportid == data->T6_reportid) {

			u8 status = payload[0];

			u8 status = payload[0];

			unsigned csum = mxt_extract_T6_csum(&payload[1]);



			crc = mxt_extract_T6_csum(&payload[1]);

			if (crc != data->config_crc) {

				data->config_crc = crc;

				complete(&data->crc_completion);

			}



			dev_dbg(dev, "Status: %02x Config Checksum: %06x\n",

			dev_dbg(dev, "Status: %02x Config Checksum: %06x\n",

				status, csum);

				status, data->config_crc);





			if (status & MXT_T6_STATUS_RESET)

			if (status & MXT_T6_STATUS_RESET)

				complete(&data->reset_completion);

				complete(&data->reset_completion);
@@ -757,6 +769,24 @@ static int mxt_soft_reset(struct mxt_data *data) 
	return 0;

	return 0;

}

}





static void mxt_update_crc(struct mxt_data *data, u8 cmd, u8 value)

{

	/*

	 * On failure, CRC is set to 0 and config will always be

	 * downloaded.

	 */

	data->config_crc = 0;

	reinit_completion(&data->crc_completion);



	mxt_t6_command(data, cmd, value, true);



	/*

	 * Wait for crc message. On failure, CRC is set to 0 and config will

	 * always be downloaded.

	 */

	mxt_wait_for_completion(data, &data->crc_completion, MXT_CRC_TIMEOUT);

}



static int mxt_check_reg_init(struct mxt_data *data)

static int mxt_check_reg_init(struct mxt_data *data)

{

{

	const struct mxt_platform_data *pdata = data->pdata;

	const struct mxt_platform_data *pdata = data->pdata;
@@ -771,6 +801,16 @@ static int mxt_check_reg_init(struct mxt_data *data) 
		return 0;

		return 0;

	}

	}





	mxt_update_crc(data, MXT_COMMAND_REPORTALL, 1);



	if (data->config_crc == pdata->config_crc) {

		dev_info(dev, "Config CRC 0x%06X: OK\n", data->config_crc);

		return 0;

	}



	dev_info(dev, "Config CRC 0x%06X: does not match 0x%06X\n",

		 data->config_crc, pdata->config_crc);



	for (i = 0; i < data->info.object_num; i++) {

	for (i = 0; i < data->info.object_num; i++) {

		object = data->object_table + i;

		object = data->object_table + i;
@@ -790,6 +830,14 @@ static int mxt_check_reg_init(struct mxt_data *data) 
		index += size;

		index += size;

	}

	}





	mxt_update_crc(data, MXT_COMMAND_BACKUPNV, MXT_BACKUP_VALUE);



	ret = mxt_soft_reset(data);

	if (ret)

		return ret;



	dev_info(dev, "Config successfully updated\n");



	return 0;

	return 0;

}

}
@@ -929,11 +977,6 @@ static int mxt_initialize(struct mxt_data *data) 
		goto err_free_object_table;

		goto err_free_object_table;

	}

	}





	error = mxt_t6_command(data, MXT_COMMAND_BACKUPNV,

			       MXT_BACKUP_VALUE, false);

	if (!error)

		mxt_soft_reset(data);



	/* Update matrix size at info struct */

	/* Update matrix size at info struct */

	error = mxt_read_reg(client, MXT_MATRIX_X_SIZE, &val);

	error = mxt_read_reg(client, MXT_MATRIX_X_SIZE, &val);

	if (error)

	if (error)
@@ -1263,6 +1306,7 @@ static int mxt_probe(struct i2c_client *client, 




	init_completion(&data->bl_completion);

	init_completion(&data->bl_completion);

	init_completion(&data->reset_completion);

	init_completion(&data->reset_completion);

	init_completion(&data->crc_completion);





	mxt_calc_resolution(data);

	mxt_calc_resolution(data);

include/linux/i2c/atmel_mxt_ts.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -29,6 +29,7 @@ 
struct mxt_platform_data {

struct mxt_platform_data {

	const u8 *config;

	const u8 *config;

	size_t config_length;

	size_t config_length;

	u32 config_crc;





	unsigned int x_size;

	unsigned int x_size;

	unsigned int y_size;

	unsigned int y_size;