V4L/DVB: FusionHDTV: Use quick reads for I2C IR device probing

IR support on FusionHDTV cards is broken since kernel 2.6.31. One side
effect of the switch to the standard binding model for IR I2C devices
was to let i2c-core do the probing instead of the ir-kbd-i2c driver.
There is a slight difference between the two probe methods: i2c-core
uses 0-byte writes, while the ir-kbd-i2c was using 0-byte reads. As
some IR I2C devices only support reads, the new probe method fails to
detect them.

For now, revert to letting the driver do the probe, using 0-byte
reads. In the future, i2c-core will be extended to let callers of
i2c_new_probed_device() provide a custom probing function.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: "Timothy D. Lenz" <tlenz@vorgon.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/media/video/cx88/cx88-i2c.c b/drivers/media/video/cx88/cx88-i2c.c
index ee1ca39db06a..fb39f1184558 100644
--- a/drivers/media/video/cx88/cx88-i2c.c
+++ b/drivers/media/video/cx88/cx88-i2c.c
@@ -188,10 +188,24 @@ int cx88_i2c_init(struct cx88_core *core, struct pci_dev *pci)
 			0x18, 0x6b, 0x71,
 			I2C_CLIENT_END
 		};
+		const unsigned short *addrp;
 
 		memset(&info, 0, sizeof(struct i2c_board_info));
 		strlcpy(info.type, "ir_video", I2C_NAME_SIZE);
-		i2c_new_probed_device(&core->i2c_adap, &info, addr_list);
+		/*
+		 * We can't call i2c_new_probed_device() because it uses
+		 * quick writes for probing and at least some R receiver
+		 * devices only reply to reads.
+		 */
+		for (addrp = addr_list; *addrp != I2C_CLIENT_END; addrp++) {
+			if (i2c_smbus_xfer(&core->i2c_adap, *addrp, 0,
+					   I2C_SMBUS_READ, 0,
+					   I2C_SMBUS_QUICK, NULL) >= 0) {
+				info.addr = *addrp;
+				i2c_new_device(&core->i2c_adap, &info);
+				break;
+			}
+		}
 	}
 	return core->i2c_rc;
 }