V4L/DVB: FusionHDTV: Use quick reads for I2C IR device probing
authorJean Delvare <khali@linux-fr.org>
Wed, 26 May 2010 13:05:11 +0000 (10:05 -0300)
committerMauro Carvalho Chehab <mchehab@redhat.com>
Tue, 1 Jun 2010 04:23:19 +0000 (01:23 -0300)
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>
drivers/media/video/cx23885/cx23885-i2c.c
drivers/media/video/cx88/cx88-i2c.c

index 4172cb3..d4746e0 100644 (file)
@@ -365,7 +365,17 @@ int cx23885_i2c_register(struct cx23885_i2c *bus)
 
                memset(&info, 0, sizeof(struct i2c_board_info));
                strlcpy(info.type, "ir_video", I2C_NAME_SIZE);
-               i2c_new_probed_device(&bus->i2c_adap, &info, addr_list);
+               /*
+                * We can't call i2c_new_probed_device() because it uses
+                * quick writes for probing and the IR receiver device only
+                * replies to reads.
+                */
+               if (i2c_smbus_xfer(&bus->i2c_adap, addr_list[0], 0,
+                                  I2C_SMBUS_READ, 0, I2C_SMBUS_QUICK,
+                                  NULL) >= 0) {
+                       info.addr = addr_list[0];
+                       i2c_new_device(&bus->i2c_adap, &info);
+               }
        }
 
        return bus->i2c_rc;
index ee1ca39..fb39f11 100644 (file)
@@ -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;
 }