soc: fsl: cpm1: qmc: Update TRNSYNC only in transparent mode

The TRNSYNC feature is available (and enabled) only in transparent mode.

Since commit 7cc9bda9c163 ("soc: fsl: cpm1: qmc: Handle timeslot entries
at channel start() and stop()") TRNSYNC register is updated in
transparent and hdlc mode. In hdlc mode, the address of the TRNSYNC
register is used by the QMC for other internal purpose. Even if no weird
results were observed in hdlc mode, touching this register in this mode
is wrong.

Update TRNSYNC only in transparent mode.

Fixes: 7cc9bda9c163 ("soc: fsl: cpm1: qmc: Handle timeslot entries at channel start() and stop()")
Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20240808071132.149251-2-herve.codina@bootlin.com
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

diff --git a/drivers/soc/fsl/qe/qmc.c b/drivers/soc/fsl/qe/qmc.c
index 76bb496305a0e0a241c3f2acf088b94478128b4f..bacabf731dcb0058d30ec21421690e730e8a527a 100644 (file)
--- a/drivers/soc/fsl/qe/qmc.c
+++ b/drivers/soc/fsl/qe/qmc.c
@@ -940,11 +940,13 @@ static int qmc_chan_start_rx(struct qmc_chan *chan)
                goto end;
        }
 
-       ret = qmc_setup_chan_trnsync(chan->qmc, chan);
-       if (ret) {
-               dev_err(chan->qmc->dev, "chan %u: setup TRNSYNC failed (%d)\n",
-                       chan->id, ret);
-               goto end;
+       if (chan->mode == QMC_TRANSPARENT) {
+               ret = qmc_setup_chan_trnsync(chan->qmc, chan);
+               if (ret) {
+                       dev_err(chan->qmc->dev, "chan %u: setup TRNSYNC failed (%d)\n",
+                               chan->id, ret);
+                       goto end;
+               }
        }
 
        /* Restart the receiver */
@@ -982,11 +984,13 @@ static int qmc_chan_start_tx(struct qmc_chan *chan)
                goto end;
        }
 
-       ret = qmc_setup_chan_trnsync(chan->qmc, chan);
-       if (ret) {
-               dev_err(chan->qmc->dev, "chan %u: setup TRNSYNC failed (%d)\n",
-                       chan->id, ret);
-               goto end;
+       if (chan->mode == QMC_TRANSPARENT) {
+               ret = qmc_setup_chan_trnsync(chan->qmc, chan);
+               if (ret) {
+                       dev_err(chan->qmc->dev, "chan %u: setup TRNSYNC failed (%d)\n",
+                               chan->id, ret);
+                       goto end;
+               }
        }
 
        /*