Hi Libin,

On Wed, Sep 25, 2013 at 07:47:19PM -0700, Libin Yang wrote:

In the clk enable and prepare function, we will check the NULL
pointer. So it should be no problem.

I'm not sure what you mean here and unfortunately your quoting style
makes your statement appear without context.

	if (... && !IS_ERR(cam->mipi_clk)) {
		if (cam->mipi_clk)
			devm_clk_put(mcam->dev, cam->mipi_clk);
		cam->mipi_clk = NULL;
	}

might work in your setup, but it's wrong usage of the clk API. There is
no reason NULL couldn't be a valid clk pointer. Moreover I cannot find a
place in that driver that calls prepare and/or enable for the mipi_clk.
(BTW, calling clk_get_rate on a disabled clk is another thing you
shouldn't do.)

For the mipi_clk, it is shared between other components, so we put the clk it we don't use it.

There should be no problem if >1 driver holds a reference to the
clock. It's clk_disable (+ maybe clk_unprepare) you should call when you
don't need it any more. (But even having >1 driver enabling a clk isn't
a problem ...)

quoted

quoted

This patch fixes all but the last issue in this list. This patch
doesn't introduce new reasons for not building, but there are already
several bulid problems.

Care to report those?

Sure:

	  CC      drivers/media/platform/marvell-ccic/mmp-driver.o
	drivers/media/platform/marvell-ccic/mmp-driver.c: In function 'mmpcam_calc_dphy':
	drivers/media/platform/marvell-ccic/mmp-driver.c:264:15: error: 'struct mmp_camera_platform_data' has no member named 'dphy3_algo'
	drivers/media/platform/marvell-ccic/mmp-driver.c:265:7: error: 'DPHY3_ALGO_PXA910' undeclared (first use in this function)
	drivers/media/platform/marvell-ccic/mmp-driver.c:265:7: note: each undeclared identifier is reported only once for each function it appears in
	drivers/media/platform/marvell-ccic/mmp-driver.c:269:8: error: 'struct mmp_camera_platform_data' has no member named 'dphy'
	drivers/media/platform/marvell-ccic/mmp-driver.c:270:17: error: 'struct mmp_camera_platform_data' has no member named 'lane_clk'
	drivers/media/platform/marvell-ccic/mmp-driver.c:271:16: error: 'struct mmp_camera_platform_data' has no member named 'lane_clk'
	drivers/media/platform/marvell-ccic/mmp-driver.c:273:7: error: 'DPHY3_ALGO_PXA2128' undeclared (first use in this function)
	drivers/media/platform/marvell-ccic/mmp-driver.c:277:8: error: 'struct mmp_camera_platform_data' has no member named 'dphy'
	drivers/media/platform/marvell-ccic/mmp-driver.c:278:17: error: 'struct mmp_camera_platform_data' has no member named 'lane_clk'
	drivers/media/platform/marvell-ccic/mmp-driver.c:279:16: error: 'struct mmp_camera_platform_data' has no member named 'lane_clk'
	drivers/media/platform/marvell-ccic/mmp-driver.c:308:7: error: 'struct mmp_camera_platform_data' has no member named 'dphy'
	drivers/media/platform/marvell-ccic/mmp-driver.c:312:104: error: 'struct mmp_camera_platform_data' has no member named 'dphy'
	drivers/media/platform/marvell-ccic/mmp-driver.c:312:120: error: 'struct mmp_camera_platform_data' has no member named 'dphy'
	drivers/media/platform/marvell-ccic/mmp-driver.c:312:136: error: 'struct mmp_camera_platform_data' has no member named 'dphy'
	drivers/media/platform/marvell-ccic/mmp-driver.c: In function 'mmpcam_probe':
	drivers/media/platform/marvell-ccic/mmp-driver.c:385:24: error: 'struct mmp_camera_platform_data' has no member named 'mclk_min'
	drivers/media/platform/marvell-ccic/mmp-driver.c:386:24: error: 'struct mmp_camera_platform_data' has no member named 'mclk_src'
	drivers/media/platform/marvell-ccic/mmp-driver.c:387:24: error: 'struct mmp_camera_platform_data' has no member named 'mclk_div'
	drivers/media/platform/marvell-ccic/mmp-driver.c:388:24: error: 'struct mmp_camera_platform_data' has no member named 'bus_type'
	drivers/media/platform/marvell-ccic/mmp-driver.c:389:20: error: 'struct mmp_camera_platform_data' has no member named 'dphy'
	drivers/media/platform/marvell-ccic/mmp-driver.c:391:20: error: 'struct mmp_camera_platform_data' has no member named 'lane'

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |