[PATCH v2 1/1] UPSTREAM: drm/bridge: it6505: fix hibernate to resume no display issue

[Pin-yen Lin]

Hi Kuro,

On Mon, Mar 4, 2024 at 11:08 AM kuro <kuro.chung at ite.com.tw> wrote:
>
> From: kuro chung <kuro.chung at ite.com.tw>
>
> ITE added a FIFO reset bit for input video. When system power resume,
> the TTL input of it6505 may get some noise before video signal stable
> and the hardware function reset is required.
> But the input FIFO reset will also trigger error interrupts of output module rising.
> Thus, it6505 have to wait a period can clear those expected error interrupts
> caused by manual hardware reset in one interrupt handler calling to avoid interrupt looping.
>
> Signed-off-by: Allen Chen <allen.chen at ite.corp-partner.google.com>
> (cherry picked from commit Iaa3cd9da92a625496f579d87d0ab74ca9c4937c4)
>
> BUG=None
> TEST=None
>
> Change-Id: Iaa3cd9da92a625496f579d87d0ab74ca9c4937c4

Again, please remove the gerrit-specific lines like "BUG=",
"Change-Id", and the "cherry picked from commit ...".
> ---
>  drivers/gpu/drm/bridge/ite-it6505.c | 54 ++++++++++++++++++++++++-----
>  1 file changed, 45 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
> index b53da9bb65a16..e592e14a48578 100644
> --- a/drivers/gpu/drm/bridge/ite-it6505.c
> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
> @@ -1318,6 +1318,8 @@ static void it6505_video_reset(struct it6505 *it6505)
>         it6505_set_bits(it6505, REG_DATA_MUTE_CTRL, EN_VID_MUTE, EN_VID_MUTE);
>         it6505_set_bits(it6505, REG_INFOFRAME_CTRL, EN_VID_CTRL_PKT, 0x00);
>         it6505_set_bits(it6505, REG_RESET_CTRL, VIDEO_RESET, VIDEO_RESET);
> +       it6505_set_bits(it6505, REG_VID_BUS_CTRL1, TX_FIFO_RESET, 0x02);
> +       it6505_set_bits(it6505, REG_VID_BUS_CTRL1, TX_FIFO_RESET, 0x00);
>         it6505_set_bits(it6505, REG_501_FIFO_CTRL, RST_501_FIFO, RST_501_FIFO);
>         it6505_set_bits(it6505, REG_501_FIFO_CTRL, RST_501_FIFO, 0x00);
>         it6505_set_bits(it6505, REG_RESET_CTRL, VIDEO_RESET, 0x00);
> @@ -2480,10 +2482,6 @@ static void it6505_irq_video_fifo_error(struct it6505 *it6505)
>         struct device *dev = &it6505->client->dev;
>
>         DRM_DEV_DEBUG_DRIVER(dev, "video fifo overflow interrupt");
> -       it6505->auto_train_retry = AUTO_TRAIN_RETRY;
> -       flush_work(&it6505->link_works);
> -       it6505_stop_hdcp(it6505);
> -       it6505_video_reset(it6505);
>  }
>
>  static void it6505_irq_io_latch_fifo_overflow(struct it6505 *it6505)
> @@ -2491,10 +2489,6 @@ static void it6505_irq_io_latch_fifo_overflow(struct it6505 *it6505)
>         struct device *dev = &it6505->client->dev;
>
>         DRM_DEV_DEBUG_DRIVER(dev, "IO latch fifo overflow interrupt");
> -       it6505->auto_train_retry = AUTO_TRAIN_RETRY;
> -       flush_work(&it6505->link_works);
> -       it6505_stop_hdcp(it6505);
> -       it6505_video_reset(it6505);
>  }
>
>  static bool it6505_test_bit(unsigned int bit, const unsigned int *addr)
> @@ -2502,6 +2496,46 @@ static bool it6505_test_bit(unsigned int bit, const unsigned int *addr)
>         return 1 & (addr[bit / BITS_PER_BYTE] >> (bit % BITS_PER_BYTE));
>  }
>
> +static bool it6505_is_video_error_int(const int *int_status)
> +{
> +       if ((it6505_test_bit(BIT_INT_VID_FIFO_ERROR, (unsigned int *)int_status)) || (it6505_test_bit(BIT_INT_IO_FIFO_OVERFLOW, (unsigned int *)int_status)))
> +               return 1;
> +       return 0;
> +}
> +
> +static void it6505_irq_video_error_handler(struct it6505 *it6505)
> +{
> +       struct device *dev = &it6505->client->dev;
> +       int int_status[3] = {0};
> +       int reg_0d;
> +       int i;
> +
> +       it6505->auto_train_retry = AUTO_TRAIN_RETRY;
> +       flush_work(&it6505->link_works);
> +       it6505_stop_hdcp(it6505);
> +       it6505_video_reset(it6505);
> +
> +       DRM_DEV_DEBUG_DRIVER(dev, "Video Error reset wait video...");
> +
> +       for (i = 0; i < 10; i++) {
> +               usleep_range(10000, 11000);
> +               int_status[2] = it6505_read(it6505, INT_STATUS_03);
> +               reg_0d = it6505_read(it6505, REG_SYSTEM_STS);
> +               it6505_write(it6505, INT_STATUS_03, int_status[2]);
> +
> +               DRM_DEV_DEBUG_DRIVER(dev, "reg08 = 0x%02x", int_status[2]);
> +               DRM_DEV_DEBUG_DRIVER(dev, "reg0D = 0x%02x", reg_0d);
> +
> +               if ((reg_0d & VIDEO_STB) && (reg_0d >= 0))
> +                       break;
> +
> +               if (it6505_is_video_error_int(int_status)) {
> +                       it6505_video_reset(it6505);
> +                       DRM_DEV_DEBUG_DRIVER(dev, "Video Error reset wait video (%d)", i);
> +               }
> +       }
> +}
> +
>  static irqreturn_t it6505_int_threaded_handler(int unused, void *data)
>  {
>         struct it6505 *it6505 = data;
> @@ -2522,7 +2556,7 @@ static irqreturn_t it6505_int_threaded_handler(int unused, void *data)
>                 { BIT_INT_VID_FIFO_ERROR, it6505_irq_video_fifo_error },
>                 { BIT_INT_IO_FIFO_OVERFLOW, it6505_irq_io_latch_fifo_overflow },
>         };
> -       int int_status[3], i;
> +       int int_status[3], i, reg_0d;
>
>         if (it6505->enable_drv_hold || !it6505->powered)
>                 return IRQ_HANDLED;
> @@ -2550,6 +2584,8 @@ static irqreturn_t it6505_int_threaded_handler(int unused, void *data)
>                         if (it6505_test_bit(irq_vec[i].bit, (unsigned int *)int_status))
>                                 irq_vec[i].handler(it6505);
>                 }
> +               if (it6505_is_video_error_int(int_status))
> +                       it6505_irq_video_error_handler(it6505);
>         }
>
>         pm_runtime_put_sync(dev);
> --
> 2.25.1
>

Did you check my comments in v1? Please reply if you don't agree with
those comments.

By the way, some mails are bounced back because of the address
changes. Please refer to the MAINTINERS file on the latest kernel (not
ChromeOS v5.15 downstream branch) for the contacts.

Regards,
Pin-yen