From 1bc2a79a4cde5f703b33342f2fcea8af208614ed Mon Sep 17 00:00:00 2001 From: Sai Pavan Boddu Date: Tue, 1 Mar 2022 09:16:50 +0100 Subject: i2c: i2c-cdns: Start read transaction after write to transfer_size reg Avoid a race condition where read transaction is started keeping expected bytes as 0. Which sometimes would result in sending STOP signal as no data is expected. Observed on QEMU platform. Signed-off-by: Sai Pavan Boddu Reviewed-by: Ashok Reddy Soma Signed-off-by: Michal Simek Link: https://lore.kernel.org/r/487c8026791bfd60719403a2df2c54bb0ae99232.1646122610.git.michal.simek@xilinx.com --- drivers/i2c/i2c-cdns.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/i2c/i2c-cdns.c') diff --git a/drivers/i2c/i2c-cdns.c b/drivers/i2c/i2c-cdns.c index a650dd69b89..5736afb4519 100644 --- a/drivers/i2c/i2c-cdns.c +++ b/drivers/i2c/i2c-cdns.c @@ -375,7 +375,6 @@ static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, curr_recv_count = recv_count; } } else if (recv_count && !hold_quirk && !curr_recv_count) { - writel(addr, ®s->address); if (recv_count > CDNS_I2C_TRANSFER_SIZE) { writel(CDNS_I2C_TRANSFER_SIZE, ®s->transfer_size); @@ -384,6 +383,7 @@ static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, writel(recv_count, ®s->transfer_size); curr_recv_count = recv_count; } + writel(addr, ®s->address); } } -- cgit v1.2.3 From 94b3f3fc7d5eece585a688061fa7a32a1a1c8495 Mon Sep 17 00:00:00 2001 From: Sai Pavan Boddu Date: Tue, 1 Mar 2022 09:16:51 +0100 Subject: i2c: i2c-cdns: Fix write transaction state Start write transfer after loading data to FIFO. Signed-off-by: Sai Pavan Boddu Reviewed-by: Ashok Reddy Soma Signed-off-by: Michal Simek Link: https://lore.kernel.org/r/f0b3e443daa7758e00dfdcc245cf6b2120b0e907.1646122610.git.michal.simek@xilinx.com --- drivers/i2c/i2c-cdns.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/i2c/i2c-cdns.c') diff --git a/drivers/i2c/i2c-cdns.c b/drivers/i2c/i2c-cdns.c index 5736afb4519..07d53be11f1 100644 --- a/drivers/i2c/i2c-cdns.c +++ b/drivers/i2c/i2c-cdns.c @@ -251,6 +251,7 @@ static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, u8 *cur_data = data; struct cdns_i2c_regs *regs = i2c_bus->regs; u32 ret; + bool start = 1; /* Set the controller in Master transmit mode and clear FIFO */ setbits_le32(®s->control, CDNS_I2C_CONTROL_CLR_FIFO); @@ -269,6 +270,11 @@ static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, while (len-- && !is_arbitration_lost(regs)) { writel(*(cur_data++), ®s->data); + /* Trigger write only after loading data */ + if (start) { + writel(addr, ®s->address); + start = 0; + } if (len && readl(®s->transfer_size) == CDNS_I2C_FIFO_DEPTH) { ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP | CDNS_I2C_INTERRUPT_ARBLOST); -- cgit v1.2.3 From f76f86029d75df2546e734e3ae1a50fa62d72526 Mon Sep 17 00:00:00 2001 From: Sai Pavan Boddu Date: Tue, 1 Mar 2022 09:16:52 +0100 Subject: i2c: i2c-cdns: Prevent early termination of write During sequential loading of data, hold the bus to prevent controller from sending stop signal in case no data is available in fifo. Signed-off-by: Sai Pavan Boddu Reviewed-by: Ashok Reddy Soma Signed-off-by: Michal Simek Link: https://lore.kernel.org/r/2407b39d305999cb42438c5423aebc3b514acabb.1646122610.git.michal.simek@xilinx.com --- drivers/i2c/i2c-cdns.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'drivers/i2c/i2c-cdns.c') diff --git a/drivers/i2c/i2c-cdns.c b/drivers/i2c/i2c-cdns.c index 07d53be11f1..0da9f6f35a9 100644 --- a/drivers/i2c/i2c-cdns.c +++ b/drivers/i2c/i2c-cdns.c @@ -257,16 +257,18 @@ static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, setbits_le32(®s->control, CDNS_I2C_CONTROL_CLR_FIFO); clrbits_le32(®s->control, CDNS_I2C_CONTROL_RW); - /* Check message size against FIFO depth, and set hold bus bit - * if it is greater than FIFO depth + /* + * For sequential data load hold the bus. */ - if (len > CDNS_I2C_FIFO_DEPTH) + if (len > 1) setbits_le32(®s->control, CDNS_I2C_CONTROL_HOLD); /* Clear the interrupts in status register */ writel(CDNS_I2C_INTERRUPTS_MASK, ®s->interrupt_status); - writel(addr, ®s->address); + /* In case of Probe (i.e no data), start the transfer */ + if (!len) + writel(addr, ®s->address); while (len-- && !is_arbitration_lost(regs)) { writel(*(cur_data++), ®s->data); -- cgit v1.2.3