i2c: imx: Fix reset of I2SR_IAL flag

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@arri.de>
Fixes: 4b775022f6fd ("i2c: imx: add struct to hold more configurable quirks")
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index c98529c76348e32097031fa4ba25fc0d7cbc0799..39e98d216016e5e4940f414f24409a269a136c0e 100644 (file)
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -412,6 +412,19 @@ static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx)
        dma->chan_using = NULL;
 }
 
+static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx, unsigned int bits)
+{
+       unsigned int temp;
+
+       /*
+        * i2sr_clr_opcode is the value to clear all interrupts. Here we want to
+        * clear only <bits>, so we write ~i2sr_clr_opcode with just <bits>
+        * toggled. This is required because i.MX needs W0C and Vybrid uses W1C.
+        */
+       temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits;
+       imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
+}
+
 static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy, bool atomic)
 {
        unsigned long orig_jiffies = jiffies;
@@ -424,8 +437,7 @@ 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;
-                       imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
+                       i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
                        return -EAGAIN;
                }
 
@@ -469,7 +481,7 @@ static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx, bool atomic)
                 */
                readb_poll_timeout_atomic(addr, regval, regval & I2SR_IIF, 5, 1000 + 100);
                i2c_imx->i2csr = regval;
-               imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);
+               i2c_imx_clear_irq(i2c_imx, I2SR_IIF | I2SR_IAL);
        } else {
                wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);
        }
@@ -623,9 +635,7 @@ 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);
-               imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
+               i2c_imx_clear_irq(i2c_imx, I2SR_IIF);
                wake_up(&i2c_imx->queue);
                return IRQ_HANDLED;
        }