[PATCH 2/7] marvell-ccic: add clock tree support for marvell-ccic driver

[PATCH 2/7] marvell-ccic: add clock tree support for marvell-ccic driver

[lbyang]

From: Libin Yang <lbyang@marvell.com>

This patch adds the clock tree support for marvell-ccic.

Signed-off-by: Libin Yang <lbyang@marvell.com>
Signed-off-by: Albert Wang <twang13@marvell.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
---
 drivers/media/platform/marvell-ccic/mcam-core.h  |    5 +++
 drivers/media/platform/marvell-ccic/mmp-driver.c |   48 ++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/media/platform/marvell-ccic/mcam-core.h b/drivers/media/platform/marvell-ccic/mcam-core.h
index be271b3..c506cd3 100644
--- a/drivers/media/platform/marvell-ccic/mcam-core.h
+++ b/drivers/media/platform/marvell-ccic/mcam-core.h
@@ -83,6 +83,8 @@ struct mcam_frame_state {
 	unsigned int delivered;
 };
 
+#define NR_MCAM_CLK 3
+
 /*
  * A description of one of our devices.
  * Locking: controlled by s_mutex.  Certain fields, however, require
@@ -113,6 +115,9 @@ struct mcam_camera {
 	bool mipi_enabled;
 	int lane;			/* lane number */
 
+	/* clock tree support */
+	struct clk *clk[NR_MCAM_CLK];
+
 	/*
 	 * Callbacks from the core to the platform code.
 	 */
diff --git a/drivers/media/platform/marvell-ccic/mmp-driver.c b/drivers/media/platform/marvell-ccic/mmp-driver.c
index 3dad182..233d0ff 100644
--- a/drivers/media/platform/marvell-ccic/mmp-driver.c
+++ b/drivers/media/platform/marvell-ccic/mmp-driver.c
@@ -35,6 +35,8 @@ MODULE_ALIAS("platform:mmp-camera");
 MODULE_AUTHOR("Jonathan Corbet <corbet@lwn.net>");
 MODULE_LICENSE("GPL");
 
+static char *mcam_clks[] = {"CCICAXICLK", "CCICFUNCLK", "CCICPHYCLK"};
+
 struct mmp_camera {
 	void *power_regs;
 	struct platform_device *pdev;
@@ -105,6 +107,26 @@ static struct mmp_camera *mmpcam_find_device(struct platform_device *pdev)
 #define REG_CCIC_DCGCR		0x28	/* CCIC dyn clock gate ctrl reg */
 #define REG_CCIC_CRCR		0x50	/* CCIC clk reset ctrl reg	*/
 
+static void mcam_clk_enable(struct mcam_camera *mcam)
+{
+	unsigned int i;
+
+	for (i = 0; i < NR_MCAM_CLK; i++) {
+		if (!IS_ERR_OR_NULL(mcam->clk[i]))
+			clk_prepare_enable(mcam->clk[i]);
+	}
+}
+
+static void mcam_clk_disable(struct mcam_camera *mcam)
+{
+	int i;
+
+	for (i = NR_MCAM_CLK - 1; i >= 0; i--) {
+		if (!IS_ERR_OR_NULL(mcam->clk[i]))
+			clk_disable_unprepare(mcam->clk[i]);
+	}
+}
+
 /*
  * Power control.
  */
@@ -135,11 +157,15 @@ static int mmpcam_power_up(struct mcam_camera *mcam)
 	mdelay(5);
 	gpio_set_value(pdata->sensor_reset_gpio, 1); /* reset is active low */
 	mdelay(5);
+
+	mcam_clk_enable(mcam);
+
 	if (mcam->bus_type == V4L2_MBUS_CSI2 && IS_ERR(cam->mipi_clk)) {
 		cam->mipi_clk = devm_clk_get(mcam->dev, "mipi");
 		if ((IS_ERR(cam->mipi_clk) && mcam->dphy[2] == 0))
 			return PTR_ERR(cam->mipi_clk);
 	}
+
 	return 0;
 }
 
@@ -163,6 +189,8 @@ static void mmpcam_power_down(struct mcam_camera *mcam)
 		devm_clk_put(mcam->dev, cam->mipi_clk);
 		cam->mipi_clk = ERR_PTR(-EINVAL);
 	}
+
+	mcam_clk_disable(mcam);
 }
 
 /*
@@ -271,6 +299,23 @@ static irqreturn_t mmpcam_irq(int irq, void *data)
 	return IRQ_RETVAL(handled);
 }
 
+static int mcam_init_clk(struct mcam_camera *mcam,
+			struct mmp_camera_platform_data *pdata)
+{
+	unsigned int i;
+
+	for (i = 0; i < NR_MCAM_CLK; i++) {
+		if (mcam_clks[i] != NULL) {
+			mcam->clk[i] = devm_clk_get(mcam->dev, mcam_clks[i]);
+			if (IS_ERR(mcam->clk[i])) {
+				dev_err(mcam->dev, "Could not get clk: %s\n",
+						mcam_clks[i]);
+				return PTR_ERR(mcam->clk[i]);
+			}
+		}
+	}
+	return 0;
+}
 
 static int mmpcam_probe(struct platform_device *pdev)
 {
@@ -338,6 +383,9 @@ static int mmpcam_probe(struct platform_device *pdev)
 		ret = -ENODEV;
 		goto out_unmap1;
 	}
+
+	mcam_init_clk(mcam, pdata);
+
 	/*
 	 * Find the i2c adapter.  This assumes, of course, that the
 	 * i2c bus is already up and functioning.
-- 
1.7.9.5

Re: [PATCH 2/7] marvell-ccic: add clock tree support for marvell-ccic driver

[Jonathan Corbet]

On Tue, 4 Jun 2013 13:42:44 +0800
lbyang <lbyang@marvell.com> wrote:

> +static void mcam_clk_enable(struct mcam_camera *mcam)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < NR_MCAM_CLK; i++) {
> +		if (!IS_ERR_OR_NULL(mcam->clk[i]))
> +			clk_prepare_enable(mcam->clk[i]);
> +	}
> +}

It seems I already acked this patch, and I won't take that back.  I
will point out, though, that IS_ERR_OR_NULL has become a sort of
lightning rod and that its use is probably best avoided.

	http://lists.infradead.org/pipermail/linux-arm-kernel/2013-January/140543.html

This relates to the use of ERR_PTR with that particular pointer value;
I still think just using NULL is better, but maybe I'm missing
something.

jon

RE: [PATCH 2/7] marvell-ccic: add clock tree support for marvell-ccic driver

[Libin Yang]

Hi Jonathan,

Do you mean using IS_ERR() here directly? I think it should be OK. I will change to IS_ERR() in next version.

Regards,
Libin  

>-----Original Message-----
>From: Jonathan Corbet [mailto:corbet@lwn.net] 
>Sent: Saturday, June 22, 2013 1:02 AM
>To: Libin Yang
>Cc: g.liakhovetski@gmx.de; mchehab@redhat.com; 
>linux-media@vger.kernel.org; albert.v.wang@gmail.com
>Subject: Re: [PATCH 2/7] marvell-ccic: add clock tree support 
>for marvell-ccic driver
>
>On Tue, 4 Jun 2013 13:42:44 +0800
>lbyang <lbyang@marvell.com> wrote:
>
>> +static void mcam_clk_enable(struct mcam_camera *mcam) {
>> +	unsigned int i;
>> +
>> +	for (i = 0; i < NR_MCAM_CLK; i++) {
>> +		if (!IS_ERR_OR_NULL(mcam->clk[i]))
>> +			clk_prepare_enable(mcam->clk[i]);
>> +	}
>> +}
>
>It seems I already acked this patch, and I won't take that 
>back.  I will point out, though, that IS_ERR_OR_NULL has 
>become a sort of lightning rod and that its use is probably 
>best avoided.
>
>	
>http://lists.infradead.org/pipermail/linux-arm-kernel/2013-Janu
>ary/140543.html
>
>This relates to the use of ERR_PTR with that particular 
>pointer value; I still think just using NULL is better, but 
>maybe I'm missing something.
>
>jon
>