linux/drivers/i2c
Conor Dooley 49e1f0fd0d i2c: microchip-core: fix "ghost" detections
Running i2c-detect currently produces an output akin to:
    0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         08 -- 0a -- 0c -- 0e --
10: 10 -- 12 -- 14 -- 16 -- UU 19 -- 1b -- 1d -- 1f
20: -- 21 -- 23 -- 25 -- 27 -- 29 -- 2b -- 2d -- 2f
30: -- -- -- -- -- -- -- -- 38 -- 3a -- 3c -- 3e --
40: 40 -- 42 -- 44 -- 46 -- 48 -- 4a -- 4c -- 4e --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: 60 -- 62 -- 64 -- 66 -- 68 -- 6a -- 6c -- 6e --
70: 70 -- 72 -- 74 -- 76 --

This happens because for an i2c_msg with a len of 0 the driver will
mark the transmission of the message as a success once the START has
been sent, without waiting for the devices on the bus to respond with an
ACK/NAK. Since i2cdetect seems to run in a tight loop over all addresses
the NAK is treated as part of the next test for the next address.

Delete the fast path that marks a message as complete when idev->msg_len
is zero after sending a START/RESTART since this isn't a valid scenario.

CC: stable@vger.kernel.org
Fixes: 64a6f1c498 ("i2c: add support for microchip fpga i2c controllers")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20241218-outbid-encounter-b2e78b1cc707@spud
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
2024-12-26 01:54:47 +01:00
..
algos
busses i2c: microchip-core: fix "ghost" detections 2024-12-26 01:54:47 +01:00
muxes i2c: Switch back to struct platform_driver::remove() 2024-11-17 11:58:14 +01:00
Kconfig i2c: Remove I2C_COMPAT config symbol and related code 2024-09-07 18:31:28 +02:00
Makefile i2c: Introduce OF component probe function 2024-11-27 12:04:10 +01:00
i2c-atr.c module: Convert symbol namespace to string literal 2024-12-02 11:34:44 -08:00
i2c-boardinfo.c
i2c-core-acpi.c i2c: acpi: Unbind mux adapters before delete 2024-05-06 09:17:38 +02:00
i2c-core-base.c The DesignWare and the Renesas I2C drivers have received most of 2024-09-21 12:46:00 +02:00
i2c-core-of-prober.c module: Convert symbol namespace to string literal 2024-12-02 11:34:44 -08:00
i2c-core-of.c Char/Misc drivers for 6.4-rc1 2023-04-27 12:07:50 -07:00
i2c-core-slave.c i2c: simplify with scoped for each OF child loop 2024-09-03 12:01:52 +02:00
i2c-core-smbus.c i2c: Fix whitespace style issue 2024-11-27 12:23:43 +01:00
i2c-core.h i2c: core: Fix atomic xfer check for non-preempt config 2024-01-06 14:10:10 +01:00
i2c-dev.c i2c: dev: Fix memory leak when underlying adapter does not support I2C 2024-11-14 11:22:57 +01:00
i2c-mux.c i2c: mux: Remove class argument from i2c_mux_add_adapter() 2024-05-13 16:13:19 +02:00
i2c-slave-eeprom.c i2c: Convert drivers to new .probe() callback 2023-03-09 21:59:30 +01:00
i2c-slave-testunit.c i2c: testunit: improve error handling for GPIO 2024-10-08 10:15:42 +02:00
i2c-smbus.c i2c: support gpio-binding for SMBAlerts 2024-10-08 11:04:20 +02:00
i2c-stub.c i2c: stub: Don't let i2c adapters declare I2C_CLASS_SPD support if they support I2C_CLASS_HWMON 2024-01-18 21:10:41 +01:00