media: s5p-cec: add NACK detection support

The s5p-cec driver returned CEC_TX_STATUS_ERROR for the NACK condition.

Some digging into the datasheet uncovered the S5P_CEC_TX_STAT1 register where
bit 0 indicates if the transmit was nacked or not.

Use this to return the correct CEC_TX_STATUS_NACK status to userspace.

This was the only driver that couldn't tell a NACK from another error, and
that was very unusual. And a potential problem for applications as well.

Tested with my Odroid-U3.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Cc: <stable@vger.kernel.org>      # for v4.12 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/platform/s5p-cec/exynos_hdmi_cecctrl.c b/drivers/media/platform/s5p-cec/exynos_hdmi_cecctrl.c
index 1edf667d562a4df64a4806e947f192aa2a24357f..146ae6f25cdbb1eee53837aa1ea28c503163ed28 100644 (file)
--- a/drivers/media/platform/s5p-cec/exynos_hdmi_cecctrl.c
+++ b/drivers/media/platform/s5p-cec/exynos_hdmi_cecctrl.c
@@ -172,7 +172,8 @@ u32 s5p_cec_get_status(struct s5p_cec_dev *cec)
 {
        u32 status = 0;
 
-       status = readb(cec->reg + S5P_CEC_STATUS_0);
+       status = readb(cec->reg + S5P_CEC_STATUS_0) & 0xf;
+       status |= (readb(cec->reg + S5P_CEC_TX_STAT1) & 0xf) << 4;
        status |= readb(cec->reg + S5P_CEC_STATUS_1) << 8;
        status |= readb(cec->reg + S5P_CEC_STATUS_2) << 16;
        status |= readb(cec->reg + S5P_CEC_STATUS_3) << 24;

diff --git a/drivers/media/platform/s5p-cec/s5p_cec.c b/drivers/media/platform/s5p-cec/s5p_cec.c
index 58d200e7c8382de8edc841b17b1022a2c15ddb85..8837e2678bdeb3507e4ebce501e5ee58216334ad 100644 (file)
--- a/drivers/media/platform/s5p-cec/s5p_cec.c
+++ b/drivers/media/platform/s5p-cec/s5p_cec.c
@@ -92,7 +92,10 @@ static irqreturn_t s5p_cec_irq_handler(int irq, void *priv)
        dev_dbg(cec->dev, "irq received\n");
 
        if (status & CEC_STATUS_TX_DONE) {
-               if (status & CEC_STATUS_TX_ERROR) {
+               if (status & CEC_STATUS_TX_NACK) {
+                       dev_dbg(cec->dev, "CEC_STATUS_TX_NACK set\n");
+                       cec->tx = STATE_NACK;
+               } else if (status & CEC_STATUS_TX_ERROR) {
                        dev_dbg(cec->dev, "CEC_STATUS_TX_ERROR set\n");
                        cec->tx = STATE_ERROR;
                } else {
@@ -135,6 +138,12 @@ static irqreturn_t s5p_cec_irq_handler_thread(int irq, void *priv)
                cec_transmit_done(cec->adap, CEC_TX_STATUS_OK, 0, 0, 0, 0);
                cec->tx = STATE_IDLE;
                break;
+       case STATE_NACK:
+               cec_transmit_done(cec->adap,
+                       CEC_TX_STATUS_MAX_RETRIES | CEC_TX_STATUS_NACK,
+                       0, 1, 0, 0);
+               cec->tx = STATE_IDLE;
+               break;
        case STATE_ERROR:
                cec_transmit_done(cec->adap,
                        CEC_TX_STATUS_MAX_RETRIES | CEC_TX_STATUS_ERROR,

diff --git a/drivers/media/platform/s5p-cec/s5p_cec.h b/drivers/media/platform/s5p-cec/s5p_cec.h
index 8bcd8dc1aeb9fb299d5b821511c9b1eba02d3c6a..86ded522ef27319a27fb72bd9f5285be6ac1ad8f 100644 (file)
--- a/drivers/media/platform/s5p-cec/s5p_cec.h
+++ b/drivers/media/platform/s5p-cec/s5p_cec.h
@@ -35,6 +35,7 @@
 #define CEC_STATUS_TX_TRANSFERRING     (1 << 1)
 #define CEC_STATUS_TX_DONE             (1 << 2)
 #define CEC_STATUS_TX_ERROR            (1 << 3)
+#define CEC_STATUS_TX_NACK             (1 << 4)
 #define CEC_STATUS_TX_BYTES            (0xFF << 8)
 #define CEC_STATUS_RX_RUNNING          (1 << 16)
 #define CEC_STATUS_RX_RECEIVING                (1 << 17)
@@ -55,6 +56,7 @@ enum cec_state {
        STATE_IDLE,
        STATE_BUSY,
        STATE_DONE,
+       STATE_NACK,
        STATE_ERROR
 };