i2c: mxs: detect No Slave Ack on SELECT in PIO mode

i2cdetect scanned i2c bus slow because the i2c-mxs driver ignored the
NO_SLAVE_ACK bit during busy-waiting loop. Thanks to the patch, the
speedup happens.

Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 65a21fed08b5..07e1be6f8992 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -307,6 +307,9 @@ static int mxs_i2c_pio_wait_xfer_end(struct mxs_i2c_dev *i2c)
         unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 
         while (readl(i2c->regs + MXS_I2C_CTRL0) & MXS_I2C_CTRL0_RUN) {
+                if (readl(i2c->regs + MXS_I2C_CTRL1) &
+                                MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
+                        return -ENXIO;
                 if (time_after(jiffies, timeout))
                         return -ETIMEDOUT;
                 cond_resched();