From: Tyrone Ting Date: Tue, 1 Oct 2024 06:28:50 +0000 (+0800) Subject: i2c: npcm: correct the read/write operation procedure X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e365422cef1ca2c964e25d26536120aab17991e2;p=users%2Fjedix%2Flinux-maple.git i2c: npcm: correct the read/write operation procedure Originally the driver uses the XMIT bit in SMBnST register to decide the upcoming i2c transaction. If XMIT bit is 1, then it will be an i2c write operation. If it's 0, then a read operation will be executed. In slave mode the XMIT bit can simply be used directly to set the state. XMIT bit can be used as an indication to the current state of the state machine during slave operation. (meaning XMIT = 1 during writing and XMIT = 0 during reading). In master operation XMIT is valid only if there are no bus errors. For example: in a multi master where the same module is switching from master to slave at runtime, and there are collisions, the XMIT bit cannot be trusted. However the maser already "knows" what the bus state is, so this bit is not needed and the driver can just track what it is currently doing. Signed-off-by: Tyrone Ting Reviewed-by: Tali Perry Signed-off-by: Andi Shyti --- diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c index bbcb4d6668ce6..2b76dbfba4381 100644 --- a/drivers/i2c/busses/i2c-npcm7xx.c +++ b/drivers/i2c/busses/i2c-npcm7xx.c @@ -1628,13 +1628,10 @@ static void npcm_i2c_irq_handle_sda(struct npcm_i2c *bus, u8 i2cst) npcm_i2c_wr_byte(bus, bus->dest_addr | BIT(0)); /* SDA interrupt, after start\restart */ } else { - if (NPCM_I2CST_XMIT & i2cst) { - bus->operation = I2C_WRITE_OPER; + if (bus->operation == I2C_WRITE_OPER) npcm_i2c_irq_master_handler_write(bus); - } else { - bus->operation = I2C_READ_OPER; + else if (bus->operation == I2C_READ_OPER) npcm_i2c_irq_master_handler_read(bus); - } } }