[PATCH v2 1/3] i2c: imx: Fix reset of I2SR_IAL flag

From: Christian Eggers
Date: Fri Oct 02 2020 - 11:25:36 EST


According to the "VFxxx Controller Reference Manual" (and the comment
block starting at line 97), Vybrid requires writing a one for clearing
an interrupt flag. Syncing the method for clearing I2SR_IIF in
i2c_imx_isr().

Signed-off-by: Christian Eggers <ceggers@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/i2c/busses/i2c-imx.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 0ab5381aa012..34648df7f1a6 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -424,7 +424,12 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy, bool a

/* check for arbitration lost */
if (temp & I2SR_IAL) {
- temp &= ~I2SR_IAL;
+ /*
+ * i2sr_clr_opcode is the value to clear all interrupts.
+ * Here we want to clear only I2SR_IAL, so we write
+ * ~i2sr_clr_opcode with just the I2SR_IAL bit toggled.
+ */
+ temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ I2SR_IAL;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
return -EAGAIN;
}
@@ -623,8 +628,12 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
if (temp & I2SR_IIF) {
/* save status register */
i2c_imx->i2csr = temp;
- temp &= ~I2SR_IIF;
- temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
+ /*
+ * i2sr_clr_opcode is the value to clear all interrupts.
+ * Here we want to clear only I2SR_IIF, so we write
+ * ~i2sr_clr_opcode with just the I2SR_IIF bit toggled.
+ */
+ temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ I2SR_IIF;
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
wake_up(&i2c_imx->queue);
return IRQ_HANDLED;
--
Christian Eggers
Embedded software developer

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