This is a note to let you know that I've just added the patch titled i2c: hisi: Avoid redundant interrupts to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: i2c-hisi-avoid-redundant-interrupts.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit e823e0028fbd44622350ee0bfc63a03ca35f6c0a Author: Yicong Yang <yangyicong@xxxxxxxxxxxxx> Date: Mon Mar 13 15:45:51 2023 +0800 i2c: hisi: Avoid redundant interrupts [ Upstream commit cc9812a3096d1986caca9a23bee99effc45c08df ] After issuing all the messages we can disable the TX_EMPTY interrupts to avoid handling redundant interrupts. For doing a sinlge bus detection (i2cdetect -y -r 0) we can reduce ~97% interrupts (before ~12000 after ~400). Signed-off-by: Sheng Feng <fengsheng5@xxxxxxxxxx> Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx> Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/i2c/busses/i2c-hisi.c b/drivers/i2c/busses/i2c-hisi.c index 72e43ecaff133..1f406e6f4ece3 100644 --- a/drivers/i2c/busses/i2c-hisi.c +++ b/drivers/i2c/busses/i2c-hisi.c @@ -315,6 +315,13 @@ static void hisi_i2c_xfer_msg(struct hisi_i2c_controller *ctlr) max_write == 0) break; } + + /* + * Disable the TX_EMPTY interrupt after finishing all the messages to + * avoid overwhelming the CPU. + */ + if (ctlr->msg_tx_idx == ctlr->msg_num) + hisi_i2c_disable_int(ctlr, HISI_I2C_INT_TX_EMPTY); } static irqreturn_t hisi_i2c_irq(int irq, void *context)