On Mon, Aug 11, 2025 at 09:49:56PM +0200, Gabor Juhos wrote:
The I2C communication is completely broken on the Armada 3700 platform since commit 0b01392c18b9 ("i2c: pxa: move to generic GPIO recovery").
For example, on the Methode uDPU board, probing of the two onboard temperature sensors fails ...
[ 7.271713] i2c i2c-0: using pinctrl states for GPIO recovery [ 7.277503] i2c i2c-0: PXA I2C adapter [ 7.282199] i2c i2c-1: using pinctrl states for GPIO recovery [ 7.288241] i2c i2c-1: PXA I2C adapter [ 7.292947] sfp sfp-eth1: Host maximum power 3.0W [ 7.299614] sfp sfp-eth0: Host maximum power 3.0W [ 7.308178] lm75 1-0048: supply vs not found, using dummy regulator [ 32.489631] lm75 1-0048: probe with driver lm75 failed with error -121 [ 32.496833] lm75 1-0049: supply vs not found, using dummy regulator [ 82.890614] lm75 1-0049: probe with driver lm75 failed with error -121
... and accessing the plugged-in SFP modules also does not work:
[ 511.298537] sfp sfp-eth1: please wait, module slow to respond [ 536.488530] sfp sfp-eth0: please wait, module slow to respond ... [ 1065.688536] sfp sfp-eth1: failed to read EEPROM: -EREMOTEIO [ 1090.888532] sfp sfp-eth0: failed to read EEPROM: -EREMOTEIO
After a discussion [1], there was an attempt to fix the problem by reverting the offending change by commit 7b211c767121 ("Revert "i2c: pxa: move to generic GPIO recovery""), but that only helped to fix the issue in the 6.1.y stable tree. The reason behind the partial succes is that there was another change in commit 20cb3fce4d60 ("i2c: Set i2c pinctrl recovery info from it's device pinctrl") in the 6.3-rc1 cycle which broke things further.
The cause of the problem is the same in case of both offending commits mentioned above. Namely, the I2C core code changes the pinctrl state to GPIO while running the recovery initialization code. Although the PXA specific initialization also does this, but the key difference is that it happens before the conrtoller is getting enabled in i2c_pxa_reset(), whereas in the case of the generic initialization it happens after that.
To resolve the problem, provide an empty init_recovery() callback function thus preventing the I2C core to call the generic recovery initialization code.
As the result this change restores the original behaviour, which in turn makes the I2C communication to work again as it can be seen from the following log:
[ 7.305277] i2c i2c-0: PXA I2C adapter [ 7.310198] i2c i2c-1: PXA I2C adapter [ 7.315012] sfp sfp-eth1: Host maximum power 3.0W [ 7.324061] lm75 1-0048: supply vs not found, using dummy regulator [ 7.331738] sfp sfp-eth0: Host maximum power 3.0W [ 7.337000] hwmon hwmon0: temp1_input not attached to any thermal zone [ 7.343593] lm75 1-0048: hwmon0: sensor 'tmp75c' [ 7.348526] lm75 1-0049: supply vs not found, using dummy regulator [ 7.356858] hwmon hwmon1: temp1_input not attached to any thermal zone [ 7.363463] lm75 1-0049: hwmon1: sensor 'tmp75c' ... [ 7.730315] sfp sfp-eth1: module Mikrotik S-RJ01 rev 1.0 sn 61B103C55C58 dc 201022 [ 7.840318] sfp sfp-eth0: module MENTECHOPTO POS22-LDCC-KR rev 1.0 sn MNC208U90009 dc 200828 [ 7.850083] mvneta d0030000.ethernet eth0: unsupported SFP module: no common interface modes [ 7.990335] hwmon hwmon2: temp1_input not attached to any thermal zone
TBH this sounds to me like trying to hack the solution and as you pointed out the problem is in pinctrl state changes. I think it may affect not only I2C case.
And I didn't get how recovery code affects the initialisation (enumeration). Do we set pin control state back and forth during probe? May be this is a root cause?
...
[1] https://lore.kernel.org/r/20230926160255.330417-1-robert.marko@sartura.hr
Can you make this a Link tag? Link: $URL #1
Cc: stable@vger.kernel.org # 6.3+ Fixes: 20cb3fce4d60 ("i2c: Set i2c pinctrl recovery info from it's device pinctrl") Signed-off-by: Gabor Juhos j4g8y7@gmail.com Signed-off-by: Imre Kaloz kaloz@openwrt.org
...
static int i2c_pxa_init_recovery(struct pxa_i2c *i2c) { struct i2c_bus_recovery_info *bri = &i2c->recovery;
return 0;}
- bri->init_recovery = i2c_pxa_init_recovery_cb;
This is unfortunate. I would keep the naming schema consistent, i.e. rename existing function and use its original name for the new callback.
bri->prepare_recovery = i2c_pxa_prepare_recovery; bri->unprepare_recovery = i2c_pxa_unprepare_recovery; bri->recover_bus = i2c_generic_scl_recovery;