Re: [PATCH 1/3] media: i2c: imx219: add support for specifying clock-frequencies
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2020-12-05 18:55:31
Also in:
linux-devicetree, linux-media, linux-renesas-soc
Hi Michael, On Sat, Dec 5, 2020 at 7:36 PM [off-list ref] wrote:
From: Michael Srba <redacted> 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 <redacted>
Thanks for your patch!
quoted hunk ↗ jump to hunk
--- a/drivers/media/i2c/imx219.c +++ b/drivers/media/i2c/imx219.c@@ -1443,13 +1443,26 @@ 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_err(dev, "could not get xclk frequency\n"); + return ret;
This breaks compatibility with existing DTBs, which do not have the clock-frequency property. For backwards compatibility, you should assume the default 24 MHz instead of returning an error.
+ }
+
+ /* 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");
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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