From c3f78043d5aea39205a14c580babd87fbdcfa148 Mon Sep 17 00:00:00 2001 From: Nick Dyer Date: Sun, 18 May 2014 23:04:46 -0700 Subject: [PATCH] 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: Nick Dyer Acked-by: Benson Leung Acked-by: Yufeng Shen Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/atmel_mxt_ts.c | 60 ++++++++++++++++++++---- include/linux/i2c/atmel_mxt_ts.h | 1 + 2 files changed, 53 insertions(+), 8 deletions(-) diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c index 278f364ec6e1..61f9ef221d12 100644 --- a/drivers/input/touchscreen/atmel_mxt_ts.c +++ b/drivers/input/touchscreen/atmel_mxt_ts.c @@ -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); diff --git a/include/linux/i2c/atmel_mxt_ts.h b/include/linux/i2c/atmel_mxt_ts.h index d26080dc606c..9f92135b6620 100644 --- a/include/linux/i2c/atmel_mxt_ts.h +++ b/include/linux/i2c/atmel_mxt_ts.h @@ -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; -- 2.30.2