V4L/DVB (13242): gspca_mr97310a: Add minimum clock divider control

When "shooting" certain (quite rare) scenes, the mr97310's compression is not
effective and it cannot keep up with the data stream. This patch adds a
minimum clock divider control, which influences the maximum framerate,
libv4l will automatically increase this minimum clockdiv control when it
detect the cam cannot keep up.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 51 insertions, 6 deletions

diff --git a/drivers/media/video/gspca/mr97310a.c b/drivers/media/video/gspca/mr97310a.c
index f282f8000701..63050f0ebfad 100644
--- a/drivers/media/video/gspca/mr97310a.c
+++ b/drivers/media/video/gspca/mr97310a.c
@@ -55,6 +55,10 @@
 #define MR97310A_GAIN_MAX               31
 #define MR97310A_GAIN_DEFAULT           25
 
+#define MR97310A_MIN_CLOCKDIV_MIN       3
+#define MR97310A_MIN_CLOCKDIV_MAX       8
+#define MR97310A_MIN_CLOCKDIV_DEFAULT   3
+
 MODULE_AUTHOR("Kyle Guinn <elyk03@gmail.com>,"
               "Theodore Kilgore <kilgota@auburn.edu>");
 MODULE_DESCRIPTION("GSPCA/Mars-Semi MR97310A USB Camera Driver");
@@ -76,6 +80,7 @@ struct sd {
         int brightness;
         u16 exposure;
         u8 gain;
+        u8 min_clockdiv;
 };
 
 struct sensor_w_data {
@@ -92,6 +97,8 @@ static int sd_setexposure(struct gspca_dev *gspca_dev, __s32 val);
 static int sd_getexposure(struct gspca_dev *gspca_dev, __s32 *val);
 static int sd_setgain(struct gspca_dev *gspca_dev, __s32 val);
 static int sd_getgain(struct gspca_dev *gspca_dev, __s32 *val);
+static int sd_setmin_clockdiv(struct gspca_dev *gspca_dev, __s32 val);
+static int sd_getmin_clockdiv(struct gspca_dev *gspca_dev, __s32 *val);
 static void setbrightness(struct gspca_dev *gspca_dev);
 static void setexposure(struct gspca_dev *gspca_dev);
 static void setgain(struct gspca_dev *gspca_dev);
@@ -160,6 +167,21 @@ static struct ctrl sd_ctrls[] = {
                 .set = sd_setgain,
                 .get = sd_getgain,
         },
+        {
+#define MIN_CLOCKDIV_IDX 4
+                {
+                        .id = V4L2_CID_PRIVATE_BASE,
+                        .type = V4L2_CTRL_TYPE_INTEGER,
+                        .name = "Minimum Clock Divider",
+                        .minimum = MR97310A_MIN_CLOCKDIV_MIN,
+                        .maximum = MR97310A_MIN_CLOCKDIV_MAX,
+                        .step = 1,
+                        .default_value = MR97310A_MIN_CLOCKDIV_DEFAULT,
+                        .flags = 0,
+                },
+                .set = sd_setmin_clockdiv,
+                .get = sd_getmin_clockdiv,
+        },
 };
 
 static const struct v4l2_pix_format vga_mode[] = {
@@ -544,14 +566,16 @@ static int sd_config(struct gspca_dev *gspca_dev,
                         gspca_dev->ctrl_dis = (1 << NORM_BRIGHTNESS_IDX) |
                                               (1 << ARGUS_QC_BRIGHTNESS_IDX);
                 else
-                        gspca_dev->ctrl_dis = (1 << ARGUS_QC_BRIGHTNESS_IDX);
+                        gspca_dev->ctrl_dis = (1 << ARGUS_QC_BRIGHTNESS_IDX) |
+                                              (1 << MIN_CLOCKDIV_IDX);
         } else {
                 /* All controls need to be disabled if VGA sensor_type is 0 */
                 if (sd->sensor_type == 0)
                         gspca_dev->ctrl_dis = (1 << NORM_BRIGHTNESS_IDX) |
                                               (1 << ARGUS_QC_BRIGHTNESS_IDX) |
                                               (1 << EXPOSURE_IDX) |
-                                              (1 << GAIN_IDX);
+                                              (1 << GAIN_IDX) |
+                                              (1 << MIN_CLOCKDIV_IDX);
                 else if (sd->do_lcd_stop)
                         /* Argus QuickClix has different brightness limits */
                         gspca_dev->ctrl_dis = (1 << NORM_BRIGHTNESS_IDX);
@@ -562,6 +586,7 @@ static int sd_config(struct gspca_dev *gspca_dev,
         sd->brightness = MR97310A_BRIGHTNESS_DEFAULT;
         sd->exposure = MR97310A_EXPOSURE_DEFAULT;
         sd->gain = MR97310A_GAIN_DEFAULT;
+        sd->min_clockdiv = MR97310A_MIN_CLOCKDIV_DEFAULT;
 
         return 0;
 }
@@ -837,6 +862,7 @@ static void setexposure(struct gspca_dev *gspca_dev)
 {
         struct sd *sd = (struct sd *) gspca_dev;
         int exposure;
+        u8 buf[2];
 
         if (gspca_dev->ctrl_dis & (1 << EXPOSURE_IDX))
                 return;
@@ -858,8 +884,8 @@ static void setexposure(struct gspca_dev *gspca_dev)
                 u8 clockdiv = (60 * sd->exposure + 7999) / 8000;
 
                 /* Limit framerate to not exceed usb bandwidth */
-                if (clockdiv < 3 && gspca_dev->width >= 320)
-                        clockdiv = 3;
+                if (clockdiv < sd->min_clockdiv && gspca_dev->width >= 320)
+                        clockdiv = sd->min_clockdiv;
                 else if (clockdiv < 2)
                         clockdiv = 2;
 
@@ -875,9 +901,10 @@ static void setexposure(struct gspca_dev *gspca_dev)
                 /* exposure register value is reversed! */
                 exposure = 511 - exposure;
 
+                buf[0] = exposure & 0xff;
+                buf[1] = exposure >> 8;
+                sensor_write_reg(gspca_dev, 0x0e, 0, buf, 2);
                 sensor_write1(gspca_dev, 0x02, clockdiv);
-                sensor_write1(gspca_dev, 0x0e, exposure & 0xff);
-                sensor_write1(gspca_dev, 0x0f, exposure >> 8);
         }
 }
 
@@ -949,6 +976,24 @@ static int sd_getgain(struct gspca_dev *gspca_dev, __s32 *val)
         return 0;
 }
 
+static int sd_setmin_clockdiv(struct gspca_dev *gspca_dev, __s32 val)
+{
+        struct sd *sd = (struct sd *) gspca_dev;
+
+        sd->min_clockdiv = val;
+        if (gspca_dev->streaming)
+                setexposure(gspca_dev);
+        return 0;
+}
+
+static int sd_getmin_clockdiv(struct gspca_dev *gspca_dev, __s32 *val)
+{
+        struct sd *sd = (struct sd *) gspca_dev;
+
+        *val = sd->min_clockdiv;
+        return 0;
+}
+
 /* Include pac common sof detection functions */
 #include "pac_common.h"