6.18-stable review patch. If anyone has any objections, please let me know.
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From: Troy Mitchell troy.mitchell@linux.spacemit.com
[ Upstream commit 25faa5364638b86ec0d0edb4486daa9d40a0be8f ]
This commit addresses two issues causing i2c detect to fail.
The identified issues are:
1. Incorrect error handling for BED (Bus Error No ACK/NAK): Before this commit, Both ALD (Arbitration Loss Detected) and BED returned -EAGAIN. 2. Missing interrupt status clear after initialization in xfer(): On the K1 SoC, simply fixing the first issue changed the error from -EAGAIN to -ETIMEOUT. Through tracing, it was determined that this is likely due to MSD (Master Stop Detected) latency issues.
That means the MSD bit in the ISR may still be set on the next transfer. As a result, the controller won't work — we can see from the scope that it doesn't issue any signal. (This only occurs during rapid consecutive I2C transfers. That explains why the issue only shows up with i2cdetect.)
With these two fixes, i2c device detection now functions correctly on the K1 SoC.
Fixes: 5ea558473fa31 ("i2c: spacemit: add support for SpacemiT K1 SoC") Tested-by: Aurelien Jarno aurelien@aurel32.net Signed-off-by: Troy Mitchell troy.mitchell@linux.spacemit.com Reviewed-by: Aurelien Jarno aurelien@aurel32.net Tested-by: Michael Opdenacker michael.opdenacker@rootcommit.com Signed-off-by: Andi Shyti andi.shyti@kernel.org Link: https://lore.kernel.org/r/20251113-fix-k1-detect-failure-v2-1-b02a9a74f65a@l... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/i2c/busses/i2c-k1.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c index 6b918770e612e..d42c03ef5db59 100644 --- a/drivers/i2c/busses/i2c-k1.c +++ b/drivers/i2c/busses/i2c-k1.c @@ -158,11 +158,16 @@ static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c) { dev_dbg(i2c->dev, "i2c error status: 0x%08x\n", i2c->status);
- if (i2c->status & (SPACEMIT_SR_BED | SPACEMIT_SR_ALD)) { + /* Arbitration Loss Detected */ + if (i2c->status & SPACEMIT_SR_ALD) { spacemit_i2c_reset(i2c); return -EAGAIN; }
+ /* Bus Error No ACK/NAK */ + if (i2c->status & SPACEMIT_SR_BED) + spacemit_i2c_reset(i2c); + return i2c->status & SPACEMIT_SR_ACKNAK ? -ENXIO : -EIO; }
@@ -224,6 +229,12 @@ static void spacemit_i2c_check_bus_release(struct spacemit_i2c_dev *i2c) } }
+static inline void +spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask) +{ + writel(mask & SPACEMIT_I2C_INT_STATUS_MASK, i2c->base + SPACEMIT_ISR); +} + static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c) { u32 val; @@ -267,12 +278,8 @@ static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c) val = readl(i2c->base + SPACEMIT_IRCR); val |= SPACEMIT_RCR_SDA_GLITCH_NOFIX; writel(val, i2c->base + SPACEMIT_IRCR); -}
-static inline void -spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask) -{ - writel(mask & SPACEMIT_I2C_INT_STATUS_MASK, i2c->base + SPACEMIT_ISR); + spacemit_i2c_clear_int_status(i2c, SPACEMIT_I2C_INT_STATUS_MASK); }
static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c)