media: ov6650: Fix arbitrary selection of master clock rate

A hardcoded 12 MHz master clock frequency has been assumed since
conversion of the driver from soc_camera sensor to a standalone V4L2
subdevice by commit 23a52386fabe ("media: ov6650: convert to standalone
v4l2 subdevice").  Fix it.

Define a static table of supported master clock rates (fix misnamed
symbol while being at it), then use v4l2_clk_get/set_rate() to obtain
a clock rate matching one of those supported.  On success, apply
respective master clock hardware divisor provided by the matching
element of the table.

[Sakari Ailus: Initialize xclk to NULL.]

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

diff --git a/drivers/media/i2c/ov6650.c b/drivers/media/i2c/ov6650.c
index f4723c0..3c8f50f 100644 (file)
--- a/drivers/media/i2c/ov6650.c
+++ b/drivers/media/i2c/ov6650.c
@@ -124,7 +124,7 @@
 
 #define DEF_AECH               0x4D
 
-#define CLKRC_6MHz             0x00
+#define CLKRC_8MHz             0x00
 #define CLKRC_12MHz            0x40
 #define CLKRC_16MHz            0x80
 #define CLKRC_24MHz            0xc0
@@ -201,6 +201,29 @@ struct ov6650 {
        u32 code;
 };
 
+struct ov6650_xclk {
+       unsigned long   rate;
+       u8              clkrc;
+};
+
+static const struct ov6650_xclk ov6650_xclk[] = {
+{
+       .rate   = 8000000,
+       .clkrc  = CLKRC_8MHz,
+},
+{
+       .rate   = 12000000,
+       .clkrc  = CLKRC_12MHz,
+},
+{
+       .rate   = 16000000,
+       .clkrc  = CLKRC_16MHz,
+},
+{
+       .rate   = 24000000,
+       .clkrc  = CLKRC_24MHz,
+},
+};
 
 static u32 ov6650_codes[] = {
        MEDIA_BUS_FMT_YUYV8_2X8,
@@ -774,7 +797,7 @@ static int ov6650_reset(struct i2c_client *client)
 }
 
 /* program default register values */
-static int ov6650_prog_dflt(struct i2c_client *client)
+static int ov6650_prog_dflt(struct i2c_client *client, u8 clkrc)
 {
        int ret;
 
@@ -782,7 +805,7 @@ static int ov6650_prog_dflt(struct i2c_client *client)
 
        ret = ov6650_reg_write(client, REG_COMA, 0);    /* ~COMA_RESET */
        if (!ret)
-               ret = ov6650_reg_write(client, REG_CLKRC, CLKRC_12MHz);
+               ret = ov6650_reg_write(client, REG_CLKRC, clkrc);
        if (!ret)
                ret = ov6650_reg_rmw(client, REG_COMB, 0, COMB_BAND_FILTER);
 
@@ -793,8 +816,10 @@ static int ov6650_video_probe(struct v4l2_subdev *sd)
 {
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct ov6650 *priv = to_ov6650(client);
-       u8              pidh, pidl, midh, midl;
-       int             ret;
+       const struct ov6650_xclk *xclk = NULL;
+       unsigned long rate;
+       u8 pidh, pidl, midh, midl;
+       int i, ret;
 
        priv->clk = v4l2_clk_get(&client->dev, NULL);
        if (IS_ERR(priv->clk)) {
@@ -803,6 +828,33 @@ static int ov6650_video_probe(struct v4l2_subdev *sd)
                return ret;
        }
 
+       rate = v4l2_clk_get_rate(priv->clk);
+       for (i = 0; rate && i < ARRAY_SIZE(ov6650_xclk); i++) {
+               if (rate != ov6650_xclk[i].rate)
+                       continue;
+
+               xclk = &ov6650_xclk[i];
+               dev_info(&client->dev, "using host default clock rate %lukHz\n",
+                        rate / 1000);
+               break;
+       }
+       for (i = 0; !xclk && i < ARRAY_SIZE(ov6650_xclk); i++) {
+               ret = v4l2_clk_set_rate(priv->clk, ov6650_xclk[i].rate);
+               if (ret || v4l2_clk_get_rate(priv->clk) != ov6650_xclk[i].rate)
+                       continue;
+
+               xclk = &ov6650_xclk[i];
+               dev_info(&client->dev, "using negotiated clock rate %lukHz\n",
+                        xclk->rate / 1000);
+               break;
+       }
+       if (!xclk) {
+               dev_err(&client->dev, "unable to get supported clock rate\n");
+               if (!ret)
+                       ret = -EINVAL;
+               goto eclkput;
+       }
+
        ret = ov6650_s_power(sd, 1);
        if (ret < 0)
                goto eclkput;
@@ -836,7 +888,7 @@ static int ov6650_video_probe(struct v4l2_subdev *sd)
 
        ret = ov6650_reset(client);
        if (!ret)
-               ret = ov6650_prog_dflt(client);
+               ret = ov6650_prog_dflt(client, xclk->clkrc);
        if (!ret) {
                struct v4l2_mbus_framefmt mf = ov6650_def_fmt;