mx2_camera: Fix regression caused by clock conversion

Since mx27 transitioned to the commmon clock framework in 3.5, the correct way
to acquire the csi clock is to get csi_ahb and csi_per clocks separately.

By not doing so the camera sensor does not probe correctly:

soc-camera-pdrv soc-camera-pdrv.0: Probing soc-camera-pdrv.0
mx2-camera mx2-camera.0: Camera driver attached to camera 0
ov2640 0-0030: Product ID error fb:fb
mx2-camera mx2-camera.0: Camera driver detached from camera 0
mx2-camera mx2-camera.0: MX2 Camera (CSI) driver probed, clock frequency: 66500000

Adapt the mx2_camera driver to the new clock framework and make it functional
again.
Tested-by: Gaëtan Carlier <gcembed@gmail.com>
Tested-by: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/platform/soc_camera/mx2_camera.c

@@ -278,7 +278,8 @@ struct mx2_camera_dev {
 	struct device		*dev;
 	struct soc_camera_host	soc_host;
 	struct soc_camera_device *icd;
-	struct clk		*clk_csi, *clk_emma_ahb, *clk_emma_ipg;
+	struct clk		*clk_emma_ahb, *clk_emma_ipg;
+	struct clk		*clk_csi_ahb, *clk_csi_per;
 
 	void __iomem		*base_csi, *base_emma;
 
@@ -464,7 +465,8 @@ static void mx2_camera_deactivate(struct mx2_camera_dev *pcdev)
 {
 	unsigned long flags;
 
-	clk_disable_unprepare(pcdev->clk_csi);
+	clk_disable_unprepare(pcdev->clk_csi_ahb);
+	clk_disable_unprepare(pcdev->clk_csi_per);
 	writel(0, pcdev->base_csi + CSICR1);
 	if (is_imx27_camera(pcdev)) {
 		writel(0, pcdev->base_emma + PRP_CNTL);
@@ -492,10 +494,14 @@ static int mx2_camera_add_device(struct soc_camera_device *icd)
 	if (pcdev->icd)
 		return -EBUSY;
 
-	ret = clk_prepare_enable(pcdev->clk_csi);
+	ret = clk_prepare_enable(pcdev->clk_csi_ahb);
 	if (ret < 0)
 		return ret;
 
+	ret = clk_prepare_enable(pcdev->clk_csi_per);
+	if (ret < 0)
+		goto exit_csi_ahb;
+
 	csicr1 = CSICR1_MCLKEN;
 
 	if (is_imx27_camera(pcdev))
@@ -512,6 +518,11 @@ static int mx2_camera_add_device(struct soc_camera_device *icd)
 		 icd->devnum);
 
 	return 0;
+
+exit_csi_ahb:
+	clk_disable_unprepare(pcdev->clk_csi_ahb);
+
+	return ret;
 }
 
 static void mx2_camera_remove_device(struct soc_camera_device *icd)
@@ -1772,10 +1783,17 @@ static int __devinit mx2_camera_probe(struct platform_device *pdev)
 		break;
 	}
 
-	pcdev->clk_csi = devm_clk_get(&pdev->dev, "ahb");
-	if (IS_ERR(pcdev->clk_csi)) {
-		dev_err(&pdev->dev, "Could not get csi clock\n");
-		err = PTR_ERR(pcdev->clk_csi);
+	pcdev->clk_csi_ahb = devm_clk_get(&pdev->dev, "ahb");
+	if (IS_ERR(pcdev->clk_csi_ahb)) {
+		dev_err(&pdev->dev, "Could not get csi ahb clock\n");
+		err = PTR_ERR(pcdev->clk_csi_ahb);
+		goto exit;
+	}
+
+	pcdev->clk_csi_per = devm_clk_get(&pdev->dev, "per");
+	if (IS_ERR(pcdev->clk_csi_per)) {
+		dev_err(&pdev->dev, "Could not get csi per clock\n");
+		err = PTR_ERR(pcdev->clk_csi_per);
 		goto exit;
 	}
 
@@ -1785,12 +1803,13 @@ static int __devinit mx2_camera_probe(struct platform_device *pdev)
 
 		pcdev->platform_flags = pcdev->pdata->flags;
 
-		rate = clk_round_rate(pcdev->clk_csi, pcdev->pdata->clk * 2);
+		rate = clk_round_rate(pcdev->clk_csi_per,
+						pcdev->pdata->clk * 2);
 		if (rate <= 0) {
 			err = -ENODEV;
 			goto exit;
 		}
-		err = clk_set_rate(pcdev->clk_csi, rate);
+		err = clk_set_rate(pcdev->clk_csi_per, rate);
 		if (err < 0)
 			goto exit;
 	}
@@ -1848,7 +1867,7 @@ static int __devinit mx2_camera_probe(struct platform_device *pdev)
 		goto exit_free_emma;
 
 	dev_info(&pdev->dev, "MX2 Camera (CSI) driver probed, clock frequency: %ld\n",
-			clk_get_rate(pcdev->clk_csi));
+			clk_get_rate(pcdev->clk_csi_per));
 
 	return 0;