Input: atmel_mxt_ts - Make wait-after-reset period compatible with all chips

PATCH Applied Iiro Valkonen 2 participants 3 messages Jul 4, 2011

Subsystems (4)

HID Input drivers Arm/Microchip (AT91) SoC support Atmel maxtouch driver

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Iiro Valkonen

author

2011-07-04 09:06 UTC #0 lore raw

PATCH 1/3 Input: atmel_mxt_ts - Make wait-after-reset period compatible with all chips

The delay before the chip can be accessed after reset varies between different chips in maXTouch family. Waiting for 200ms and then monitoring the CHG (chip is ready when the line is low) is guaranteed to work with all chips.

Signed-off-by Iiro Valkonen <[email protected]>

---
 drivers/input/touchscreen/atmel_mxt_ts.c |    4 +++-
 include/linux/i2c/atmel_mxt_ts.h         |    1 +
 2 files changed, 4 insertions(+), 1 deletions(-)

drivers/input/touchscreen/atmel_mxt_ts.c +3 -1

index 1e61387..8870e7b 100644
@@ -170,7 +170,7 @@
 #define MXT_BOOT_VALUE		0xa5
 #define MXT_BACKUP_VALUE	0x55
 #define MXT_BACKUP_TIME		25	/* msec */
-#define MXT_RESET_TIME		65	/* msec */
+#define MXT_RESET_TIME		200	/* msec */
 
 #define MXT_FWRESET_TIME	175	/* msec */

@@ -828,6 +828,8 @@ static int mxt_initialize(struct mxt_data *data)
 	mxt_write_object(data, MXT_GEN_COMMAND,
 			MXT_COMMAND_RESET, 1);
 	msleep(MXT_RESET_TIME);
+	while (data->pdata->read_chg())
+		msleep(2);
 
 	/* Update matrix size at info struct */
 	error = mxt_read_reg(client, MXT_MATRIX_X_SIZE, &val);

include/linux/i2c/atmel_mxt_ts.h +1 -0

index f027f7a..ef59c22 100644
@@ -39,6 +39,7 @@ struct mxt_platform_data {
 	unsigned int voltage;
 	unsigned char orient;
 	unsigned long irqflags;
+	u8(*read_chg) (void);
 };
 
 #endif /* __LINUX_ATMEL_MXT_TS_H */

Signature · 1 line

1.7.0.4

Dmitry Torokhov

maintainer

2011-07-04 10:04 UTC #1 lore raw

Quoted 24 lines · Iiro Valkonen

The delay before the chip can be accessed after reset varies between different chips in maXTouch family. Waiting for 200ms and then monitoring the CHG (chip is ready when the line is low) is guaranteed to work with all chips.
Signed-off-by Iiro Valkonen <[email protected]>
---
 drivers/input/touchscreen/atmel_mxt_ts.c |    4 +++-
 include/linux/i2c/atmel_mxt_ts.h         |    1 +
 2 files changed, 4 insertions(+), 1 deletions(-)
drivers/input/touchscreen/atmel_mxt_ts.c +1 -1
index 1e61387..8870e7b 100644
@@ -170,7 +170,7 @@
 #define MXT_BOOT_VALUE		0xa5
 #define MXT_BACKUP_VALUE	0x55
 #define MXT_BACKUP_TIME		25	/* msec */
-#define MXT_RESET_TIME		65	/* msec */
+#define MXT_RESET_TIME		200	/* msec */
 
 #define MXT_FWRESET_TIME	175	/* msec */
 

drivers/input/touchscreen/atmel_mxt_ts.c static int mxt_initialize(struct mxt_data *data) · line 832

Quoted 5 lines

drivers/input/touchscreen/atmel_mxt_ts.c +2 -0

@@ -828,6 +828,8 @@ static int mxt_initialize(struct mxt_data *data)
 	mxt_write_object(data, MXT_GEN_COMMAND,
 			MXT_COMMAND_RESET, 1);
 	msleep(MXT_RESET_TIME);
+	while (data->pdata->read_chg())
+		msleep(2);

I would prefer if we did not wait indefinitely but timed out after certain number of retries.

Thanks.

Signature · 1 line

Dmitry

Iiro Valkonen

author

2011-07-04 12:58 UTC #2 lore raw

Quoted 11 lines · Dmitry Torokhov

drivers/input/touchscreen/atmel_mxt_ts.c static int mxt_initialize(struct mxt_data *data) · line 832
Quoted 7 lines
drivers/input/touchscreen/atmel_mxt_ts.c +2 -0
@@ -828,6 +828,8 @@ static int mxt_initialize(struct mxt_data *data)
 	mxt_write_object(data, MXT_GEN_COMMAND,
 			MXT_COMMAND_RESET, 1);
 	msleep(MXT_RESET_TIME);
+	while (data->pdata->read_chg())
+		msleep(2);
I would prefer if we did not wait indefinitely but timed out after certain number of retries.

Thanks, that does make sense. I'll send a new version.

BR,

Signature · 1 line

Iiro