From 2ec6f246c33a0b830a6ad3171161e9d880e2251e Mon Sep 17 00:00:00 2001 From: Nuno Lucas Date: Tue, 11 Nov 2008 16:48:04 -0500 Subject: Input: usbtouchscreen - fix TSC-10 DM USB controllers without EEPROM The usbtouchscreen module implements a driver for the TSC-10 DM USB touchscreen controllers, but assumes a 2-byte response for the CMD_RESET and CMD_RATE commands, when they can be only a single byte when no EEPROM is connected. The driver worked with an earlier controller revision, but new revisions of the controller fail. It seems the problem is that the early controller had the SEL4/EEPROM-CS pin high, but the new controller has it down, making the response different. Without the fix, the controller would answer the single byte 0x06 (ACK), making the init fail with -ENODEV because buf[1] is 0xFF (as initialized before). As the single byte is the only thing we need to check it was ok, there is no need to verify the second byte. The [0x15 0x01] case is the NAK [0x15] response for when there is no data in the EEPROM [bit-0 of second byte set], so I let that be, as I don't have any controller with an EEPROM. With this patch, both the earlier and latest controller work the same. Note: This was previously submited as BUG #11961 [1] on the bugzilla tracker, but rebased to version 2.6.27.4 and with unnecessary comments and printk's removed. [1] http://bugzilla.kernel.org/show_bug.cgi?id=11961 Signed-off-by: Nuno Lucas Acked-by: Daniel Ritz Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/usbtouchscreen.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'drivers/input') diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c index fdd645c214a2..5080b26ba160 100644 --- a/drivers/input/touchscreen/usbtouchscreen.c +++ b/drivers/input/touchscreen/usbtouchscreen.c @@ -424,7 +424,7 @@ static int dmc_tsc10_init(struct usbtouch_usb *usbtouch) 0, 0, buf, 2, USB_CTRL_SET_TIMEOUT); if (ret < 0) goto err_out; - if (buf[0] != 0x06 || buf[1] != 0x00) { + if (buf[0] != 0x06) { ret = -ENODEV; goto err_out; } @@ -437,8 +437,7 @@ static int dmc_tsc10_init(struct usbtouch_usb *usbtouch) TSC10_RATE_150, 0, buf, 2, USB_CTRL_SET_TIMEOUT); if (ret < 0) goto err_out; - if ((buf[0] != 0x06 || buf[1] != 0x00) && - (buf[0] != 0x15 || buf[1] != 0x01)) { + if ((buf[0] != 0x06) && (buf[0] != 0x15 || buf[1] != 0x01)) { ret = -ENODEV; goto err_out; } -- cgit v1.2.1