Re: [PATCH v1 2/6] drm/mediatek: mtk_dpi: Add support for Pattern Generator in debugfs

["CK Hu (胡俊光)" <ck.hu@mediatek.com>]

Hi, Angelo:

On Wed, 2024-11-20 at 13:44 +0100, AngeloGioacchino Del Regno wrote:
> External email : Please do not click links or open attachments until you have verified the sender or the content.
> 
> 
> This IP includes a Pattern Generator which is useful for debugging
> and testing purposes: add the relevant register and bits to the
> mtk_dpi_regs.h header, and implement support for it in mtk_dpi.
> 
> Adding this required to introduce a .debugfs_init() callback for
> the DPI bridge, which creates a "dpi_test_pattern" file in the
> directory of the appropriate connector.
> 
> The pattern generator can generate various internal patterns and
> this submission includes support for:
>  - 256 or 1024 shades of gray in a Vertical or Horizontal Pattern
>  - Vertical Color Bars
>  - Frame border
>  - Dot Moire
> 
> This generator also supports filling the entire screen with one
> custom color, but support for that is not included in this commit.
> 
> Enabling and disabling this generator can be done by sending a
> string to the dpi_test_pattern debugfs file; the pattern is
> expected to be formatted as follows:
> 
>          <enable (1) or disable (0)> <pattern number>
> 
> where the pattern number can be a number from 0 to 7, excluding 5.
> 
> Of course 5 is excluded because that activates custom color fill
> which, again, is not supported in this commit.

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c      | 107 ++++++++++++++++++++++++
>  drivers/gpu/drm/mediatek/mtk_dpi_regs.h |   4 +
>  2 files changed, 111 insertions(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 20a9d589fd75..c7143184e5de 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -6,6 +6,7 @@
> 
>  #include <linux/clk.h>
>  #include <linux/component.h>
> +#include <linux/debugfs.h>
>  #include <linux/interrupt.h>
>  #include <linux/kernel.h>
>  #include <linux/media-bus-format.h>
> @@ -166,6 +167,18 @@ static void mtk_dpi_mask(struct mtk_dpi *dpi, u32 offset, u32 val, u32 mask)
>         writel(tmp, dpi->regs + offset);
>  }
> 
> +static void mtk_dpi_test_pattern_en(struct mtk_dpi *dpi, u8 type, bool enable)
> +{
> +       u32 val;
> +
> +       if (enable)
> +               val = FIELD_PREP(DPI_PAT_SEL, type) | DPI_PAT_EN;
> +       else
> +               val = 0;
> +
> +       mtk_dpi_mask(dpi, DPI_PATTERN0, val, DPI_PAT_SEL | DPI_PAT_EN);
> +}
> +
>  static void mtk_dpi_sw_reset(struct mtk_dpi *dpi, bool reset)
>  {
>         mtk_dpi_mask(dpi, DPI_RET, reset ? RST : 0, RST);
> @@ -767,6 +780,99 @@ mtk_dpi_bridge_mode_valid(struct drm_bridge *bridge,
>         return MODE_OK;
>  }
> 
> +static int mtk_dpi_debug_tp_show(struct seq_file *m, void *arg)
> +{
> +       struct mtk_dpi *dpi = m->private;
> +       bool en;
> +       u32 val;
> +
> +       if (!dpi)
> +               return -EINVAL;
> +
> +       val = readl(dpi->regs + DPI_PATTERN0);
> +       en = val & DPI_PAT_EN;
> +       val = FIELD_GET(DPI_PAT_SEL, val);
> +
> +       seq_printf(m, "DPI Test Pattern: %s\n", en ? "Enabled" : "Disabled");
> +
> +       if (en) {
> +               seq_printf(m, "Internal pattern %d: ", val);
> +               switch (val) {
> +               case 0:
> +                       seq_puts(m, "256 Vertical Gray\n");
> +                       break;
> +               case 1:
> +                       seq_puts(m, "1024 Vertical Gray\n");
> +                       break;
> +               case 2:
> +                       seq_puts(m, "256 Horizontal Gray\n");
> +                       break;
> +               case 3:
> +                       seq_puts(m, "1024 Horizontal Gray\n");
> +                       break;
> +               case 4:
> +                       seq_puts(m, "Vertical Color bars\n");
> +                       break;
> +               case 6:
> +                       seq_puts(m, "Frame border\n");
> +                       break;
> +               case 7:
> +                       seq_puts(m, "Dot moire\n");
> +                       break;
> +               default:
> +                       seq_puts(m, "Invalid selection\n");
> +                       break;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static ssize_t mtk_dpi_debug_tp_write(struct file *file, const char __user *ubuf,
> +                                     size_t len, loff_t *offp)
> +{
> +       struct seq_file *m = file->private_data;
> +       u32 en, type;
> +       char buf[6];
> +
> +       if (!m || !m->private || *offp || len > sizeof(buf) - 1)
> +               return -EINVAL;
> +
> +       memset(buf, 0, sizeof(buf));
> +       if (copy_from_user(buf, ubuf, len))
> +               return -EFAULT;
> +
> +       if (sscanf(buf, "%u %u", &en, &type) != 2)
> +               return -EINVAL;
> +
> +       if (en < 0 || en > 1 || type < 0 || type > 7)
> +               return -EINVAL;
> +
> +       mtk_dpi_test_pattern_en((struct mtk_dpi *)m->private, type, en);
> +       return len;
> +}
> +
> +static int mtk_dpi_debug_tp_open(struct inode *inode, struct file *file)
> +{
> +       return single_open(file, mtk_dpi_debug_tp_show, inode->i_private);
> +}
> +
> +static const struct file_operations mtk_dpi_debug_tp_fops = {
> +       .owner = THIS_MODULE,
> +       .open = mtk_dpi_debug_tp_open,
> +       .read = seq_read,
> +       .write = mtk_dpi_debug_tp_write,
> +       .llseek = seq_lseek,
> +       .release = single_release,
> +};
> +
> +static void mtk_dpi_debugfs_init(struct drm_bridge *bridge, struct dentry *root)
> +{
> +       struct mtk_dpi *dpi = bridge_to_dpi(bridge);
> +
> +       debugfs_create_file("dpi_test_pattern", 0640, root, dpi, &mtk_dpi_debug_tp_fops);
> +}
> +
>  static const struct drm_bridge_funcs mtk_dpi_bridge_funcs = {
>         .attach = mtk_dpi_bridge_attach,
>         .mode_set = mtk_dpi_bridge_mode_set,
> @@ -779,6 +885,7 @@ static const struct drm_bridge_funcs mtk_dpi_bridge_funcs = {
>         .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
>         .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
>         .atomic_reset = drm_atomic_helper_bridge_reset,
> +       .debugfs_init = mtk_dpi_debugfs_init,
>  };
> 
>  void mtk_dpi_start(struct device *dev)
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi_regs.h b/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> index 62bd4931b344..a0b1d18bbbf7 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> @@ -235,4 +235,8 @@
>  #define MATRIX_SEL_RGB_TO_JPEG         0
>  #define MATRIX_SEL_RGB_TO_BT601                2
> 
> +#define DPI_PATTERN0           0xf00
> +#define DPI_PAT_EN                     BIT(0)
> +#define DPI_PAT_SEL                    GENMASK(6, 4)
> +
>  #endif /* __MTK_DPI_REGS_H */
> --
> 2.47.0
>