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Input: atmel_mxt_ts - implement CRC check for configuration data

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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: Nick Dyer <nick.dyer@itdev.co.uk>
Acked-by: Benson Leung <bleung@chromium.org>
Acked-by: Yufeng Shen <miletus@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Nick Dyer 2014-05-18 23:04:46 -07:00 committed by Dmitry Torokhov
parent 7bed680561
commit c3f78043d5
2 changed files with 53 additions and 8 deletions
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60
drivers/input/touchscreen/atmel_mxt_ts.c
View File

@ -188,6 +188,7 @@
#define MXT_BACKUP_TIME 50 /* msec */
#define MXT_RESET_TIME 200 /* msec */
#define MXT_RESET_TIMEOUT 3000 /* msec */
#define MXT_CRC_TIMEOUT 1000 /* msec */
#define MXT_FW_RESET_TIME 3000 /* msec */
#define MXT_FW_CHG_TIMEOUT 300 /* msec */
@ -259,6 +260,7 @@ struct mxt_data {
unsigned int max_x;
unsigned int max_y;
bool in_bootloader;
u32 config_crc;
/* Cached parameters from object table */
u8 T6_reportid;
@ -272,6 +274,9 @@ struct mxt_data {
/* for reset handling */
struct completion reset_completion;
/* for config update handling */
struct completion crc_completion;
};
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);
}
@ -654,6 +659,7 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data)
struct device *dev = &data->client->dev;
u8 reportid;
bool update_input = false;
u32 crc;
do {
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) {
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",
status, csum);
status, data->config_crc);
if (status & MXT_T6_STATUS_RESET)
complete(&data->reset_completion);
@ -757,6 +769,24 @@ static int mxt_soft_reset(struct mxt_data *data)
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)
{
const struct mxt_platform_data *pdata = data->pdata;
@ -771,6 +801,16 @@ static int mxt_check_reg_init(struct mxt_data *data)
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++) {
object = data->object_table + i;
@ -790,6 +830,14 @@ static int mxt_check_reg_init(struct mxt_data *data)
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;
}
@ -929,11 +977,6 @@ static int mxt_initialize(struct mxt_data *data)
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 */
error = mxt_read_reg(client, MXT_MATRIX_X_SIZE, &val);
if (error)
@ -1263,6 +1306,7 @@ static int mxt_probe(struct i2c_client *client,
init_completion(&data->bl_completion);
init_completion(&data->reset_completion);
init_completion(&data->crc_completion);
mxt_calc_resolution(data);

1
include/linux/i2c/atmel_mxt_ts.h
View File

@ -29,6 +29,7 @@
struct mxt_platform_data {
const u8 *config;
size_t config_length;
u32 config_crc;
unsigned int x_size;
unsigned int y_size;