5.4-stable review patch. If anyone has any objections, please let me know.
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From: Andreas Kemnade andreas@kemnade.info
commit 285df995f90e3d61d97f327d34b9659d92313314 upstream.
On the GTA04A5 writing a reset command to the gyroscope causes IRQ storms because NACK IRQs are enabled and therefore triggered but not acked.
Sending a reset command to the gyroscope by i2cset 1 0x69 0x14 0xb6 with an additional debug print in the ISR (not the thread) itself causes
[ 363.353515] i2c i2c-1: ioctl, cmd=0x720, arg=0xbe801b00 [ 363.359039] omap_i2c 48072000.i2c: addr: 0x0069, len: 2, flags: 0x0, stop: 1 [ 363.366180] omap_i2c 48072000.i2c: IRQ LL (ISR = 0x1110) [ 363.371673] omap_i2c 48072000.i2c: IRQ (ISR = 0x0010) [ 363.376892] omap_i2c 48072000.i2c: IRQ LL (ISR = 0x0102) [ 363.382263] omap_i2c 48072000.i2c: IRQ LL (ISR = 0x0102) [ 363.387664] omap_i2c 48072000.i2c: IRQ LL (ISR = 0x0102) repeating till infinity [...] (0x2 = NACK, 0x100 = Bus free, which is not enabled) Apparently no other IRQ bit gets set, so this stalls.
Do not ignore enabled interrupts and make sure they are acked. If the NACK IRQ is not needed, it should simply not enabled, but according to the above log, caring about it is necessary unless the Bus free IRQ is enabled and handled. The assumption that is will always come with a ARDY IRQ, which was the idea behind ignoring it, proves wrong. It is true for simple reads from an unused address.
To still avoid the i2cdetect trouble which is the reason for commit c770657bd261 ("i2c: omap: Fix standard mode false ACK readings"), avoid doing much about NACK in omap_i2c_xfer_data() which is used by both IRQ mode and polling mode, so also the false detection fix is extended to polling usage and IRQ storms are avoided.
By changing this, the hardirq handler is not needed anymore to filter stuff.
The mentioned gyro reset now just causes a -ETIMEDOUT instead of hanging the system.
Fixes: c770657bd261 ("i2c: omap: Fix standard mode false ACK readings"). CC: stable@kernel.org Signed-off-by: Andreas Kemnade andreas@kemnade.info Tested-by: Nishanth Menon nm@ti.com Reviewed-by: Aniket Limaye a-limaye@ti.com Signed-off-by: Andi Shyti andi.shyti@kernel.org Link: https://lore.kernel.org/r/20250228140420.379498-1-andreas@kemnade.info Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/i2c/busses/i2c-omap.c | 26 +++++++------------------- 1 file changed, 7 insertions(+), 19 deletions(-)
--- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -1049,23 +1049,6 @@ static int omap_i2c_transmit_data(struct return 0; }
-static irqreturn_t -omap_i2c_isr(int irq, void *dev_id) -{ - struct omap_i2c_dev *omap = dev_id; - irqreturn_t ret = IRQ_HANDLED; - u16 mask; - u16 stat; - - stat = omap_i2c_read_reg(omap, OMAP_I2C_STAT_REG); - mask = omap_i2c_read_reg(omap, OMAP_I2C_IE_REG) & ~OMAP_I2C_STAT_NACK; - - if (stat & mask) - ret = IRQ_WAKE_THREAD; - - return ret; -} - static int omap_i2c_xfer_data(struct omap_i2c_dev *omap) { u16 bits; @@ -1096,8 +1079,13 @@ static int omap_i2c_xfer_data(struct oma }
if (stat & OMAP_I2C_STAT_NACK) { - err |= OMAP_I2C_STAT_NACK; + omap->cmd_err |= OMAP_I2C_STAT_NACK; omap_i2c_ack_stat(omap, OMAP_I2C_STAT_NACK); + + if (!(stat & ~OMAP_I2C_STAT_NACK)) { + err = -EAGAIN; + break; + } }
if (stat & OMAP_I2C_STAT_AL) { @@ -1480,7 +1468,7 @@ omap_i2c_probe(struct platform_device *p IRQF_NO_SUSPEND, pdev->name, omap); else r = devm_request_threaded_irq(&pdev->dev, omap->irq, - omap_i2c_isr, omap_i2c_isr_thread, + NULL, omap_i2c_isr_thread, IRQF_NO_SUSPEND | IRQF_ONESHOT, pdev->name, omap);