media: imx477: Compute link frequency PLL settings

Rather than the hard coded PLL settings for fixed frequencies,
compute the PLL settings based on device tree, validating that
the specified rate can be achieved.

Signed-off-by: Dave Stevenson <[email protected]>

Author: 6by9

drivers/media/i2c/imx477.c

@@ -87,6 +87,12 @@ MODULE_PARM_DESC(trigger_mode, "Set vsync trigger mode: 1=source, 2=sink");
 #define IMX477_DGTL_GAIN_DEFAULT	0x0100
 #define IMX477_DGTL_GAIN_STEP		1
 
+#define IMX477_REG_IOP_SYSCK_DIV	CCI_REG8(0x030b)
+  #define IMX477_IOP_SYSCK_DIV		0x02
+#define IMX477_REG_IOP_PREDIV		CCI_REG8(0x030d)
+  #define IMX477_IOP_PREDIV		0x02
+#define IMX477_REG_IOP_MPY		CCI_REG16(0x030e)
+
 /* Test Pattern Control */
 #define IMX477_REG_TEST_PATTERN		CCI_REG8(0x0600)
 #define IMX477_TEST_PATTERN_DISABLE	0
@@ -161,83 +167,6 @@ struct imx477_mode {
 	struct imx477_reg_list reg_list;
 };
 
-/* Link frequency setup */
-enum {
-	IMX477_LINK_FREQ_450MHZ,
-	IMX477_LINK_FREQ_453MHZ,
-	IMX477_LINK_FREQ_456MHZ,
-	IMX477_LINK_FREQ_459MHZ,
-	IMX477_LINK_FREQ_462MHZ,
-	IMX477_LINK_FREQ_498MHZ,
-};
-
-static const s64 link_freqs[] = {
-	[IMX477_LINK_FREQ_450MHZ] = 450000000,
-	[IMX477_LINK_FREQ_453MHZ] = 453000000,
-	[IMX477_LINK_FREQ_456MHZ] = 456000000,
-	[IMX477_LINK_FREQ_459MHZ] = 459000000,
-	[IMX477_LINK_FREQ_462MHZ] = 462000000,
-	[IMX477_LINK_FREQ_498MHZ] = 498000000,
-};
-
-/* 450MHz is the nominal "default" link frequency */
-static const struct cci_reg_sequence link_450Mhz_regs[] = {
-	{CCI_REG8(0x030e), 0x00},
-	{CCI_REG8(0x030f), 0x96},
-};
-
-static const struct cci_reg_sequence link_453Mhz_regs[] = {
-	{CCI_REG8(0x030e), 0x00},
-	{CCI_REG8(0x030f), 0x97},
-};
-
-static const struct cci_reg_sequence link_456Mhz_regs[] = {
-	{CCI_REG8(0x030e), 0x00},
-	{CCI_REG8(0x030f), 0x98},
-};
-
-static const struct cci_reg_sequence link_459Mhz_regs[] = {
-	{CCI_REG8(0x030e), 0x00},
-	{CCI_REG8(0x030f), 0x99},
-};
-
-static const struct cci_reg_sequence link_462Mhz_regs[] = {
-	{CCI_REG8(0x030e), 0x00},
-	{CCI_REG8(0x030f), 0x9a},
-};
-
-static const struct cci_reg_sequence link_498Mhz_regs[] = {
-	{CCI_REG8(0x030e), 0x00},
-	{CCI_REG8(0x030f), 0xa6},
-};
-
-static const struct imx477_reg_list link_freq_regs[] = {
-	[IMX477_LINK_FREQ_450MHZ] = {
-		.regs = link_450Mhz_regs,
-		.num_of_regs = ARRAY_SIZE(link_450Mhz_regs)
-	},
-	[IMX477_LINK_FREQ_453MHZ] = {
-		.regs = link_453Mhz_regs,
-		.num_of_regs = ARRAY_SIZE(link_453Mhz_regs)
-	},
-	[IMX477_LINK_FREQ_456MHZ] = {
-		.regs = link_456Mhz_regs,
-		.num_of_regs = ARRAY_SIZE(link_456Mhz_regs)
-	},
-	[IMX477_LINK_FREQ_459MHZ] = {
-		.regs = link_459Mhz_regs,
-		.num_of_regs = ARRAY_SIZE(link_459Mhz_regs)
-	},
-	[IMX477_LINK_FREQ_462MHZ] = {
-		.regs = link_462Mhz_regs,
-		.num_of_regs = ARRAY_SIZE(link_462Mhz_regs)
-	},
-	[IMX477_LINK_FREQ_498MHZ] = {
-		.regs = link_498Mhz_regs,
-		.num_of_regs = ARRAY_SIZE(link_498Mhz_regs)
-	},
-};
-
 static const struct cci_reg_sequence mode_common_regs[] = {
 	{CCI_REG8(0x0136), 0x18},
 	{CCI_REG8(0x0137), 0x00},
@@ -565,8 +494,8 @@ static const struct cci_reg_sequence mode_common_regs[] = {
 	{CCI_REG8(0x9e9f), 0x00},
 	{CCI_REG8(0x0301), 0x05},
 	{CCI_REG8(0x0303), 0x02},
-	{CCI_REG8(0x030b), 0x02},
-	{CCI_REG8(0x030d), 0x02},
+	{IMX477_REG_IOP_SYSCK_DIV, IMX477_IOP_SYSCK_DIV},
+	{IMX477_REG_IOP_PREDIV, IMX477_IOP_PREDIV},
 	{CCI_REG8(0x0310), 0x01},
 	{CCI_REG8(0x0820), 0x07},
 	{CCI_REG8(0x0821), 0x08},
@@ -1109,7 +1038,8 @@ struct imx477 {
 	struct v4l2_ctrl *vblank;
 	struct v4l2_ctrl *hblank;
 
-	unsigned int link_freq_idx;
+	u64 link_freq_value;
+	u16 iop_pll_mpy;
 
 	/* Current mode */
 	const struct imx477_mode *mode;
@@ -1614,7 +1544,7 @@ static int imx477_get_selection(struct v4l2_subdev *sd,
 static int imx477_start_streaming(struct imx477 *imx477)
 {
 	struct i2c_client *client = v4l2_get_subdevdata(&imx477->sd);
-	const struct imx477_reg_list *reg_list, *freq_regs;
+	const struct imx477_reg_list *reg_list;
 	const struct imx477_reg_list *extra_regs;
 	int ret, tm;
 
@@ -1626,10 +1556,9 @@ static int imx477_start_streaming(struct imx477 *imx477)
 		cci_multi_reg_write(imx477->regmap, extra_regs->regs,
 				    extra_regs->num_of_regs, &ret);
 
-		/* Update the link frequency registers */
-		freq_regs = &link_freq_regs[imx477->link_freq_idx];
-		cci_multi_reg_write(imx477->regmap, freq_regs->regs,
-				    freq_regs->num_of_regs, &ret);
+		/* Update the link frequency PLL multiplier register */
+		cci_write(imx477->regmap, IMX477_REG_IOP_MPY,
+			  imx477->iop_pll_mpy, &ret);
 
 		if (ret) {
 			dev_err(&client->dev, "%s failed to set common settings\n",
@@ -1922,7 +1851,7 @@ static int imx477_init_controls(struct imx477 *imx477)
 	imx477->link_freq =
 		v4l2_ctrl_new_int_menu(ctrl_hdlr, &imx477_ctrl_ops,
 				       V4L2_CID_LINK_FREQ, 0, 0,
-				       &link_freqs[imx477->link_freq_idx]);
+				       &imx477->link_freq_value);
 	if (imx477->link_freq)
 		imx477->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
 
@@ -2021,6 +1950,25 @@ static void imx477_free_controls(struct imx477 *imx477)
 	mutex_destroy(&imx477->mutex);
 }
 
+static int imx477_check_link_freq(u64 link_frequency, u16 *mpy_out)
+{
+	u64 mpy = link_frequency * 2 * IMX477_IOP_SYSCK_DIV * IMX477_IOP_PREDIV;
+	u64 tmp;
+
+	do_div(mpy, IMX477_XCLK_FREQ);
+
+	tmp = mpy * (IMX477_XCLK_FREQ / IMX477_IOP_PREDIV);
+	do_div(tmp, IMX477_IOP_SYSCK_DIV * 2);
+
+	if (tmp != link_frequency)
+		return -EINVAL;
+
+	if (mpy_out)
+		*mpy_out = mpy;
+
+	return 0;
+}
+
 static int imx477_check_hwcfg(struct device *dev, struct imx477 *imx477)
 {
 	struct fwnode_handle *endpoint;
@@ -2053,16 +2001,16 @@ static int imx477_check_hwcfg(struct device *dev, struct imx477 *imx477)
 		goto error_out;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(link_freqs); i++) {
-		if (link_freqs[i] == ep_cfg.link_frequencies[0]) {
-			imx477->link_freq_idx = i;
+	for (i = 0; i < ep_cfg.nr_of_link_frequencies; i++) {
+		if (!imx477_check_link_freq(ep_cfg.link_frequencies[i],
+					    &imx477->iop_pll_mpy)) {
+			imx477->link_freq_value = ep_cfg.link_frequencies[i];
 			break;
 		}
 	}
 
-	if (i == ARRAY_SIZE(link_freqs)) {
-		dev_err(dev, "Link frequency not supported: %lld\n",
-			ep_cfg.link_frequencies[0]);
+	if (i == ep_cfg.nr_of_link_frequencies) {
+		dev_err(dev, "No supported link frequency configured\n");
 			ret = -EINVAL;
 			goto error_out;
 	}