Re: [PATCH v2 1/3] media: i2c: imx219: add support for specifying clock-frequencies
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: 2020-12-18 10:49:28
Also in:
linux-devicetree, linux-media, linux-renesas-soc
Hi Michael On Sun, 6 Dec 2020 at 17:29, [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>
As the listed maintainer of this driver I'll say that I don't have any objections to the aim of this patch. Those who know the clock infrastructure far better than me are recommending alternative methods of implementing this, so I'll leave it up to them to give a Reviewed-by. When that's happened I'll add an ack. Dave
quoted hunk ↗ jump to hunk
--- 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
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