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i2c: imx: fix missing stop condition in single-master mode

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A regression was introduced with the implementation of single-master
mode, preventing proper stop conditions from being generated. Devices
that require a valid stop condition, such as EEPROMs, fail to function
correctly as a result.

The issue only affects devices with the single-master property enabled.

This commit resolves the issue by re-enabling I2C bus busy bit (IBB)
polling for single-master mode when generating a stop condition. The fix
further ensures that the i2c_imx->stopped flag is cleared at the start
of each transfer, allowing the stop condition to be correctly generated
in i2c_imx_stop().

According to the reference manual (IMX8MMRM, Rev. 2, 09/2019, page
5270), polling the IBB bit to determine if the bus is free is only
necessary in multi-master mode. Consequently, the IBB bit is not polled
for the start condition in single-master mode.

Fixes: 6692694aca ("i2c: imx: do not poll for bus busy in single master mode")
Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20241216151829.74056-1-eichest@gmail.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
This commit is contained in:
Stefan Eichenberger
2024-12-16 16:16:40 +01:00
committed by Andi Shyti
parent 4bbf9020be
commit 768776dd4e
1 changed files with 3 additions and 5 deletions
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8
drivers/i2c/busses/i2c-imx.c
View File

@@ -532,22 +532,20 @@ static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx)
static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy, bool atomic)
{
bool multi_master = i2c_imx->multi_master;
unsigned long orig_jiffies = jiffies;
unsigned int temp;
if (!i2c_imx->multi_master)
return 0;
while (1) {
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
/* check for arbitration lost */
if (temp & I2SR_IAL) {
if (multi_master && (temp & I2SR_IAL)) {
i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
return -EAGAIN;
}
if (for_busy && (temp & I2SR_IBB)) {
if (for_busy && (!multi_master || (temp & I2SR_IBB))) {
i2c_imx->stopped = 0;
break;
}