[PATCH v2 1/3] media: i2c: imx219: add support for specifying clock-frequencies

[michael.srba at seznam.cz]

From: Michael Srba <Michael.Srba at seznam.cz>

This patch adds 1% tolerance on input clock, similar to other camera sensor
drivers. It also allows for specifying the actual clock in the device tree,
instead of relying on it being already set to the right frequency (which is
often not the case).

Signed-off-by: Michael Srba <Michael.Srba at seznam.cz>

---

changes since v1: default to exactly 24MHz when `clock-frequency` is not present

---
 drivers/media/i2c/imx219.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
index f64c0ef7a897..b6500e2ab19e 100644
--- a/drivers/media/i2c/imx219.c
+++ b/drivers/media/i2c/imx219.c
@@ -1443,13 +1443,28 @@ static int imx219_probe(struct i2c_client *client)
 		return PTR_ERR(imx219->xclk);
 	}
 
-	imx219->xclk_freq = clk_get_rate(imx219->xclk);
-	if (imx219->xclk_freq != IMX219_XCLK_FREQ) {
+	ret = fwnode_property_read_u32(dev_fwnode(dev), "clock-frequency", &imx219->xclk_freq);
+	if (ret) {
+		dev_warn(dev, "could not get xclk frequency\n");
+
+		/* default to 24MHz */
+		imx219->xclk_freq = 24000000;
+	}
+
+	/* this driver currently expects 24MHz; allow 1% tolerance */
+	if (imx219->xclk_freq < 23760000 || imx219->xclk_freq > 24240000) {
 		dev_err(dev, "xclk frequency not supported: %d Hz\n",
 			imx219->xclk_freq);
 		return -EINVAL;
 	}
 
+	ret = clk_set_rate(imx219->xclk, imx219->xclk_freq);
+	if (ret) {
+		dev_err(dev, "could not set xclk frequency\n");
+		return ret;
+	}
+
+
 	ret = imx219_get_regulators(imx219);
 	if (ret) {
 		dev_err(dev, "failed to get regulators\n");
-- 
2.29.2