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 controller is getting enabled in i2c_pxa_reset(), whereas in the case of the generic initialization it happens after that.
Change the code to reset the controller only before the first transfer instead of before registering the controller. This ensures that the controller is not enabled at the time when the generic recovery code performs the pinctrl state changes, thus avoids the problem described above.
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:
[ 7.363250] i2c i2c-0: using pinctrl states for GPIO recovery [ 7.369041] i2c i2c-0: PXA I2C adapter [ 7.373673] i2c i2c-1: using pinctrl states for GPIO recovery [ 7.379742] i2c i2c-1: PXA I2C adapter [ 7.384506] sfp sfp-eth1: Host maximum power 3.0W [ 7.393013] sfp sfp-eth0: Host maximum power 3.0W [ 7.399266] lm75 1-0048: supply vs not found, using dummy regulator [ 7.407257] hwmon hwmon0: temp1_input not attached to any thermal zone [ 7.413863] lm75 1-0048: hwmon0: sensor 'tmp75c' [ 7.418746] lm75 1-0049: supply vs not found, using dummy regulator [ 7.426371] hwmon hwmon1: temp1_input not attached to any thermal zone [ 7.432972] lm75 1-0049: hwmon1: sensor 'tmp75c' [ 7.755092] sfp sfp-eth1: module MENTECHOPTO POS22-LDCC-KR rev 1.0 sn MNC208U90009 dc 200828 [ 7.764997] mvneta d0040000.ethernet eth1: unsupported SFP module: no common interface modes [ 7.785362] sfp sfp-eth0: module Mikrotik S-RJ01 rev 1.0 sn 61B103C55C58 dc 201022 [ 7.803426] hwmon hwmon2: temp1_input not attached to any thermal zone
Link: https://lore.kernel.org/r/20230926160255.330417-1-robert.marko@sartura.hr #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 --- Changes in v3: - rebase on tip of i2c/for-current - rework the patch and use a different approach which does not requires modification in the I2C core code and update commit description acccordingly - remove Imre's SoB tag, it should have been a Reviewed-by tag, but due to the rework this is an entirely different patch so that does not apply anyway - use Link tag for the URL of the referenced LKML thread - Link to v2: https://lore.kernel.org/r/20250811-i2c-pxa-fix-i2c-communication-v2-2-ca42ea...
Changes in v2: - rebase and retest on tip of i2c/for-current - Link to v1: https://lore.kernel.org/r/20250511-i2c-pxa-fix-i2c-communication-v1-2-e9097d... --- drivers/i2c/busses/i2c-pxa.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c index 968a8b8794dac3398a68d827c567aa5bb73ae3d7..70acf33e1d573231f84a1f09cffb376a8277351d 100644 --- a/drivers/i2c/busses/i2c-pxa.c +++ b/drivers/i2c/busses/i2c-pxa.c @@ -268,6 +268,7 @@ struct pxa_i2c { struct pinctrl *pinctrl; struct pinctrl_state *pinctrl_default; struct pinctrl_state *pinctrl_recovery; + bool reset_before_xfer; };
#define _IBMR(i2c) ((i2c)->reg_ibmr) @@ -1144,6 +1145,11 @@ static int i2c_pxa_xfer(struct i2c_adapter *adap, { struct pxa_i2c *i2c = adap->algo_data;
+ if (i2c->reset_before_xfer) { + i2c_pxa_reset(i2c); + i2c->reset_before_xfer = false; + } + return i2c_pxa_internal_xfer(i2c, msgs, num, i2c_pxa_do_xfer); }
@@ -1521,7 +1527,16 @@ static int i2c_pxa_probe(struct platform_device *dev) } }
- i2c_pxa_reset(i2c); + /* + * Skip reset on Armada 3700 when recovery is used to avoid + * controller hang due to the pinctrl state changes done by + * the generic recovery initialization code. The reset will + * be performed later, prior to the first transfer. + */ + if (i2c_type == REGS_A3700 && i2c->adap.bus_recovery_info) + i2c->reset_before_xfer = true; + else + i2c_pxa_reset(i2c);
ret = i2c_add_numbered_adapter(&i2c->adap); if (ret < 0)