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authorJean Delvare <jdelvare@suse.de>2019-07-04 05:34:02 -0400
committerWolfram Sang <wsa@the-dreams.de>2019-07-05 14:59:10 -0400
commited6182a83924c2385679afd5a3b9cd3d41e2ef44 (patch)
tree82d651d87bf82737a30eee47db3cf4b4b9ab904a /Documentation/i2c
parent051d769f0a36b4642897d909cef980f944ae20ab (diff)
i2c: i801: Documentation update
The i2c-i801 driver documentation needs some dusting: * Mention disable_features flag 0x20. * The i2c_ec driver has been removed from the kernel long ago. Driver i2c-scmi serves the same purpose for more recent hardware. * Replace obsolete /proc paths with equivalent /sys paths. Signed-off-by: Jean Delvare <jdelvare@suse.de> Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'Documentation/i2c')
-rw-r--r--Documentation/i2c/busses/i2c-i80116
1 files changed, 8 insertions, 8 deletions
diff --git a/Documentation/i2c/busses/i2c-i801 b/Documentation/i2c/busses/i2c-i801
index 04b5de80ce4e..f426c13c63a9 100644
--- a/Documentation/i2c/busses/i2c-i801
+++ b/Documentation/i2c/busses/i2c-i801
@@ -60,6 +60,7 @@ question doesn't work as intended for whatever reason. Bit values:
60 0x02 disable the block buffer 60 0x02 disable the block buffer
61 0x08 disable the I2C block read functionality 61 0x08 disable the I2C block read functionality
62 0x10 don't use interrupts 62 0x10 don't use interrupts
63 0x20 disable SMBus Host Notify
63 64
64 65
65Description 66Description
@@ -120,16 +121,15 @@ BIOS to enable it, it means it has been hidden by the BIOS code. Asus is
120well known for first doing this on their P4B motherboard, and many other 121well known for first doing this on their P4B motherboard, and many other
121boards after that. Some vendor machines are affected as well. 122boards after that. Some vendor machines are affected as well.
122 123
123The first thing to try is the "i2c_ec" ACPI driver. It could be that the 124The first thing to try is the "i2c-scmi" ACPI driver. It could be that the
124SMBus was hidden on purpose because it'll be driven by ACPI. If the 125SMBus was hidden on purpose because it'll be driven by ACPI. If the
125i2c_ec driver works for you, just forget about the i2c-i801 driver and 126i2c-scmi driver works for you, just forget about the i2c-i801 driver and
126don't try to unhide the ICH SMBus. Even if i2c_ec doesn't work, you 127don't try to unhide the ICH SMBus. Even if i2c-scmi doesn't work, you
127better make sure that the SMBus isn't used by the ACPI code. Try loading 128better make sure that the SMBus isn't used by the ACPI code. Try loading
128the "fan" and "thermal" drivers, and check in /proc/acpi/fan and 129the "fan" and "thermal" drivers, and check in /sys/class/thermal. If you
129/proc/acpi/thermal_zone. If you find anything there, it's likely that 130find a thermal zone with type "acpitz", it's likely that the ACPI is
130the ACPI is accessing the SMBus and it's safer not to unhide it. Only 131accessing the SMBus and it's safer not to unhide it. Only once you are
131once you are certain that ACPI isn't using the SMBus, you can attempt 132certain that ACPI isn't using the SMBus, you can attempt to unhide it.
132to unhide it.
133 133
134In order to unhide the SMBus, we need to change the value of a PCI 134In order to unhide the SMBus, we need to change the value of a PCI
135register before the kernel enumerates the PCI devices. This is done in 135register before the kernel enumerates the PCI devices. This is done in