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.d...@itdev.co.uk>
Acked-by: Benson Leung <ble...@chromium.org>
---
drivers/input/touchscreen/atmel_mxt_ts.c | 55 +++++++++++++++++++++++++-----
include/linux/i2c/atmel_mxt_ts.h | 1 +
2 files changed, 48 insertions(+), 8 deletions(-)
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c
b/drivers/input/touchscreen/atmel_mxt_ts.c
index 82b001d..434e674 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -194,6 +194,7 @@
#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 */
@@ -268,6 +269,7 @@ struct mxt_data {
u16 mem_size;
struct bin_attribute mem_access_attr;
bool debug_enabled;
+ u32 config_crc;
/* Cached parameters from object table */
u8 T6_reportid;
@@ -282,6 +284,9 @@ struct mxt_data {
/* for reset handling */
struct completion reset_completion;
+ /* for reset handling */
+ struct completion crc_completion;
+
/* Enable reporting of input events */
bool enable_reporting;
};
@@ -655,7 +660,7 @@ 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);
}
@@ -674,6 +679,7 @@ static irqreturn_t
mxt_process_messages_until_invalid(struct mxt_data *data)
u8 reportid;
bool update_input = false;
bool dump;
+ u32 crc;
do {
if (mxt_read_message(data, &message)) {
@@ -686,9 +692,15 @@ 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);
@@ -784,6 +796,19 @@ 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;
+ INIT_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;
@@ -798,6 +823,16 @@ 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;
+ } else {
+ 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;
@@ -817,6 +852,14 @@ 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 written\n");
+
return 0;
}
@@ -982,11 +1025,6 @@ 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)
@@ -1392,6 +1430,7 @@ 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 d26080d..9f92135 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;
--
1.7.10.4
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