Re: [PATCH v4 23/36] media: imx: Add MIPI CSI-2 Receiver subdev driver

From: Steve Longerbeam
Date: Fri Feb 17 2017 - 13:27:16 EST

On 02/17/2017 06:16 AM, Philipp Zabel wrote:
On Fri, 2017-02-17 at 11:47 +0100, Philipp Zabel wrote:
On Wed, 2017-02-15 at 18:19 -0800, Steve Longerbeam wrote:
+static void csi2_dphy_init(struct csi2_dev *csi2)
+ /*
+ * FIXME: 0x14 is derived from a fixed D-PHY reference
+ * clock from the HSI_TX PLL, and a fixed target lane max
+ * bandwidth of 300 Mbps. This value should be derived

If the table in is correct,
this should be 850 Mbps. Where does this 300 Mbps value come from?

I got it, the dptdin_map value for 300 Mbps is 0x14 in the Rockchip DSI
driver. But that value is written to the register as HSFREQRANGE_SEL(x):

#define HSFREQRANGE_SEL(val) (((val) & 0x3f) << 1)

Ah you are right, 0x14 would be a "testdin" value of 0x0a, which from
the Rockchip table would be 950 MHz per lane.

But thanks for pointing the table at That table is what
should be referenced in the above comment (850 MHz per lane
for a 27MHz reference clock). I will update the comment based
on that table.


which is 0x28. Further, the Rockchip D-PHY probably is another version,
as its max_mbps goes up to 1500.