drivers/i2c/busses/i2c-microchip-corei2c.c | 4 ++++ 1 file changed, 4 insertions(+)
From: Conor Dooley <conor.dooley@microchip.com>
Introducing support for smbus re-broke i2cdetect, causing it to detect
devices at every i2c address, just as it did prior to being fixed in
commit 49e1f0fd0d4cb ("i2c: microchip-core: fix "ghost" detections").
This was caused by an oversight, where the new smbus code failed to
check the return value of mchp_corei2c_xfer(). Check it, and propagate
any errors.
Fixes: d6ceb40538263 ("i2c: microchip-corei2c: add smbus support")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
v2:
- replace "if (ret)" with "if (ret < 0)" because the xfer callback,
which the smbus code re-uses, can return positive numbers in success
cases.
CC: Conor Dooley <conor.dooley@microchip.com>
CC: Daire McNamara <daire.mcnamara@microchip.com>
CC: Andi Shyti <andi.shyti@kernel.org>
CC: linux-i2c@vger.kernel.org
CC: linux-kernel@vger.kernel.org
---
drivers/i2c/busses/i2c-microchip-corei2c.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/i2c/busses/i2c-microchip-corei2c.c b/drivers/i2c/busses/i2c-microchip-corei2c.c
index 492bf4c34722c..7505bce3a06cd 100644
--- a/drivers/i2c/busses/i2c-microchip-corei2c.c
+++ b/drivers/i2c/busses/i2c-microchip-corei2c.c
@@ -435,6 +435,7 @@ static int mchp_corei2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned
u8 tx_buf[I2C_SMBUS_BLOCK_MAX + 2];
u8 rx_buf[I2C_SMBUS_BLOCK_MAX + 1];
int num_msgs = 1;
+ int ret;
msgs[CORE_I2C_SMBUS_MSG_WR].addr = addr;
msgs[CORE_I2C_SMBUS_MSG_WR].flags = 0;
@@ -506,6 +507,9 @@ static int mchp_corei2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned
}
mchp_corei2c_xfer(&idev->adapter, msgs, num_msgs);
+ if (ret < 0)
+ return ret;
+
if (read_write == I2C_SMBUS_WRITE || size <= I2C_SMBUS_BYTE_DATA)
return 0;
--
2.45.2Hi Conor,
kernel test robot noticed the following build warnings:
[auto build test WARNING on andi-shyti/i2c/i2c-host]
[also build test WARNING on linus/master v6.16-rc3 next-20250627]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Conor-Dooley/i2c-microchip-core-re-fix-fake-detections-w-i2cdetect/20250627-001626
base: https://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux.git i2c/i2c-host
patch link: https://lore.kernel.org/r/20250626-unusable-excess-da94ebc218e8%40spud
patch subject: [PATCH v2] i2c: microchip-core: re-fix fake detections w/ i2cdetect
config: riscv-randconfig-002-20250628 (https://download.01.org/0day-ci/archive/20250628/202506282209.FXWbPIPz-lkp@intel.com/config)
compiler: clang version 16.0.6 (https://github.com/llvm/llvm-project 7cbf1a2591520c2491aa35339f227775f4d3adf6)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250628/202506282209.FXWbPIPz-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506282209.FXWbPIPz-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/i2c/busses/i2c-microchip-corei2c.c:510:6: warning: variable 'ret' is uninitialized when used here [-Wuninitialized]
if (ret < 0)
^~~
drivers/i2c/busses/i2c-microchip-corei2c.c:438:9: note: initialize the variable 'ret' to silence this warning
int ret;
^
= 0
1 warning generated.
vim +/ret +510 drivers/i2c/busses/i2c-microchip-corei2c.c
428
429 static int mchp_corei2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
430 char read_write, u8 command,
431 int size, union i2c_smbus_data *data)
432 {
433 struct i2c_msg msgs[2];
434 struct mchp_corei2c_dev *idev = i2c_get_adapdata(adap);
435 u8 tx_buf[I2C_SMBUS_BLOCK_MAX + 2];
436 u8 rx_buf[I2C_SMBUS_BLOCK_MAX + 1];
437 int num_msgs = 1;
438 int ret;
439
440 msgs[CORE_I2C_SMBUS_MSG_WR].addr = addr;
441 msgs[CORE_I2C_SMBUS_MSG_WR].flags = 0;
442
443 if (read_write == I2C_SMBUS_READ && size <= I2C_SMBUS_BYTE)
444 msgs[CORE_I2C_SMBUS_MSG_WR].flags = I2C_M_RD;
445
446 if (read_write == I2C_SMBUS_WRITE && size <= I2C_SMBUS_WORD_DATA)
447 msgs[CORE_I2C_SMBUS_MSG_WR].len = size;
448
449 if (read_write == I2C_SMBUS_WRITE && size > I2C_SMBUS_BYTE) {
450 msgs[CORE_I2C_SMBUS_MSG_WR].buf = tx_buf;
451 msgs[CORE_I2C_SMBUS_MSG_WR].buf[0] = command;
452 }
453
454 if (read_write == I2C_SMBUS_READ && size >= I2C_SMBUS_BYTE_DATA) {
455 msgs[CORE_I2C_SMBUS_MSG_WR].buf = tx_buf;
456 msgs[CORE_I2C_SMBUS_MSG_WR].buf[0] = command;
457 msgs[CORE_I2C_SMBUS_MSG_RD].addr = addr;
458 msgs[CORE_I2C_SMBUS_MSG_RD].flags = I2C_M_RD;
459 num_msgs = 2;
460 }
461
462 if (read_write == I2C_SMBUS_READ && size > I2C_SMBUS_QUICK)
463 msgs[CORE_I2C_SMBUS_MSG_WR].len = 1;
464
465 switch (size) {
466 case I2C_SMBUS_QUICK:
467 msgs[CORE_I2C_SMBUS_MSG_WR].buf = NULL;
468 return 0;
469 case I2C_SMBUS_BYTE:
470 if (read_write == I2C_SMBUS_WRITE)
471 msgs[CORE_I2C_SMBUS_MSG_WR].buf = &command;
472 else
473 msgs[CORE_I2C_SMBUS_MSG_WR].buf = &data->byte;
474 break;
475 case I2C_SMBUS_BYTE_DATA:
476 if (read_write == I2C_SMBUS_WRITE) {
477 msgs[CORE_I2C_SMBUS_MSG_WR].buf[1] = data->byte;
478 } else {
479 msgs[CORE_I2C_SMBUS_MSG_RD].len = size - 1;
480 msgs[CORE_I2C_SMBUS_MSG_RD].buf = &data->byte;
481 }
482 break;
483 case I2C_SMBUS_WORD_DATA:
484 if (read_write == I2C_SMBUS_WRITE) {
485 msgs[CORE_I2C_SMBUS_MSG_WR].buf[1] = data->word & 0xFF;
486 msgs[CORE_I2C_SMBUS_MSG_WR].buf[2] = (data->word >> 8) & 0xFF;
487 } else {
488 msgs[CORE_I2C_SMBUS_MSG_RD].len = size - 1;
489 msgs[CORE_I2C_SMBUS_MSG_RD].buf = rx_buf;
490 }
491 break;
492 case I2C_SMBUS_BLOCK_DATA:
493 if (read_write == I2C_SMBUS_WRITE) {
494 int data_len;
495
496 data_len = data->block[0];
497 msgs[CORE_I2C_SMBUS_MSG_WR].len = data_len + 2;
498 for (int i = 0; i <= data_len; i++)
499 msgs[CORE_I2C_SMBUS_MSG_WR].buf[i + 1] = data->block[i];
500 } else {
501 msgs[CORE_I2C_SMBUS_MSG_RD].len = I2C_SMBUS_BLOCK_MAX + 1;
502 msgs[CORE_I2C_SMBUS_MSG_RD].buf = rx_buf;
503 }
504 break;
505 default:
506 return -EOPNOTSUPP;
507 }
508
509 mchp_corei2c_xfer(&idev->adapter, msgs, num_msgs);
> 510 if (ret < 0)
511 return ret;
512
513 if (read_write == I2C_SMBUS_WRITE || size <= I2C_SMBUS_BYTE_DATA)
514 return 0;
515
516 switch (size) {
517 case I2C_SMBUS_WORD_DATA:
518 data->word = (rx_buf[0] | (rx_buf[1] << 8));
519 break;
520 case I2C_SMBUS_BLOCK_DATA:
521 if (rx_buf[0] > I2C_SMBUS_BLOCK_MAX)
522 rx_buf[0] = I2C_SMBUS_BLOCK_MAX;
523 /* As per protocol first member of block is size of the block. */
524 for (int i = 0; i <= rx_buf[0]; i++)
525 data->block[i] = rx_buf[i];
526 break;
527 }
528
529 return 0;
530 }
531
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Sat, Jun 28, 2025 at 10:28:45PM +0800, kernel test robot wrote: > Hi Conor, > > kernel test robot noticed the following build warnings: > > [auto build test WARNING on andi-shyti/i2c/i2c-host] > [also build test WARNING on linus/master v6.16-rc3 next-20250627] > [If your patch is applied to the wrong git tree, kindly drop us a note. > And when submitting patch, we suggest to use '--base' as documented in > https://git-scm.com/docs/git-format-patch#_base_tree_information] > > url: https://github.com/intel-lab-lkp/linux/commits/Conor-Dooley/i2c-microchip-core-re-fix-fake-detections-w-i2cdetect/20250627-001626 > base: https://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux.git i2c/i2c-host > patch link: https://lore.kernel.org/r/20250626-unusable-excess-da94ebc218e8%40spud > patch subject: [PATCH v2] i2c: microchip-core: re-fix fake detections w/ i2cdetect > config: riscv-randconfig-002-20250628 (https://download.01.org/0day-ci/archive/20250628/202506282209.FXWbPIPz-lkp@intel.com/config) > compiler: clang version 16.0.6 (https://github.com/llvm/llvm-project 7cbf1a2591520c2491aa35339f227775f4d3adf6) > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250628/202506282209.FXWbPIPz-lkp@intel.com/reproduce) > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > the same patch/commit), kindly add following tags > | Reported-by: kernel test robot <lkp@intel.com> > | Closes: https://lore.kernel.org/oe-kbuild-all/202506282209.FXWbPIPz-lkp@intel.com/ > > All warnings (new ones prefixed by >>): > > >> drivers/i2c/busses/i2c-microchip-corei2c.c:510:6: warning: variable 'ret' is uninitialized when used here [-Wuninitialized] > if (ret < 0) > ^~~ > drivers/i2c/busses/i2c-microchip-corei2c.c:438:9: note: initialize the variable 'ret' to silence this warning > int ret; > ^ > = 0 > 1 warning generated. Oh damn it, I accidentally committed a version that I was using to provoke the WARN while trying to understand why this was corrupting the workqueue. V3 incoming.
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