[PATCH 4/4] usb: chipidea: imx: set over current polarity per dts setting

On Tue, Jul 19, 2016 at 02:31:41AM +0000, Jun Li wrote:

Hi

quoted

-----Original Message-----
From: Peter Chen [mailto:hzpeterchen at gmail.com]
Sent: Tuesday, July 19, 2016 9:57 AM
To: Jun Li <redacted>
Cc: Peter Chen <redacted>; robh+dt at kernel.org;
shawnguo at kernel.org; devicetree at vger.kernel.org; linux-usb at vger.kernel.org;
linux-arm-kernel at lists.infradead.org
Subject: Re: [PATCH 4/4] usb: chipidea: imx: set over current polarity per
dts setting

On Mon, Jul 18, 2016 at 07:15:47PM +0800, Li Jun wrote:

quoted

With over-current-polarity property added, imx usb over current
polarity can be configed to be low or high active, since the default
setting value(0) is for active high, so keep this setting for those
legacy platforms without this property specified.

Signed-off-by: Li Jun <redacted>
---
 drivers/usb/chipidea/ci_hdrc_imx.c |  9 +++++++++
drivers/usb/chipidea/ci_hdrc_imx.h |  1 +
drivers/usb/chipidea/usbmisc_imx.c | 30 +++++++++++++++++++++++++-----
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/chipidea/ci_hdrc_imx.c

b/drivers/usb/chipidea/ci_hdrc_imx.c
index dedc33e..61e712b 100644

--- a/drivers/usb/chipidea/ci_hdrc_imx.c
+++ b/drivers/usb/chipidea/ci_hdrc_imx.c

@@ -140,6 +140,15 @@ static struct imx_usbmisc_data

*usbmisc_get_init_data(struct device *dev)

quoted

 	if (of_find_property(np, "disable-over-current", NULL))
 		data->disable_oc = 1;

+	if (!of_property_read_u32(np, "over-current-polarity", &ret))
+		data->oc_polarity = ret ? 1 : 0;
+	else
+		/*
+		 * Keep the oc polarity setting of legacy
+		 * platforms unchanged.
+		 */
+		data->oc_polarity = 1;

We may can't ensure that, since there are lots of i.mx platforms, eg from
imx27 to imx7.

If the user does not assign oc polarity at DT, we need to read it from
register.

I suppose old platforms (other than i.mx6&7) should set either
"over-current-polarity" or "disable-over-current" if want to use
"data->oc_polarity".
 

The user may use old dtb and the latest kernel, so the introduced
DT property should not affect old dtb platforms.

Do you mean read the register value before set "data->oc_polarity" here?

yes, if there is a dts property, read it from DT; else, read it from the register.

if (!of_property_read_u32(np, "over-current-polarity", &ret))
	data->oc_polarity = ret ? 1 : 0;
else
	/*
	 * Keep the oc polarity setting of legacy
	 * platforms unchanged.
	 */
	data->oc_polarity = readl(oc_polarity);

Then, when you set register for oc polarity, you can depend on the
flag.
	reg = readl(usbmisc->base + data->index * 4);
	value = data->oc_polarity ? MX6_BM_OVER_CUR_POLARITY : 0;
	writel(reg | value, usbmisc->base + data->index * 4);
	

Even with that, as I still can't ensure all i.mx platforms have the same
mapping:
0 <--> active high.
1 <--> active low.
How should I set "data->oc_polarity" accordingly?

Just keep current register value unchanging if there is no dts property.

Peter

Li Jun

quoted

Peter

quoted

+
 	if (of_find_property(np, "external-vbus-divider", NULL))
 		data->evdo = 1;

diff --git a/drivers/usb/chipidea/ci_hdrc_imx.h

b/drivers/usb/chipidea/ci_hdrc_imx.h
index 635717e..409aa5ca8 100644

--- a/drivers/usb/chipidea/ci_hdrc_imx.h
+++ b/drivers/usb/chipidea/ci_hdrc_imx.h

@@ -17,6 +17,7 @@ struct imx_usbmisc_data {
 	int index;

 	unsigned int disable_oc:1; /* over current detect disabled */
+	unsigned int oc_polarity:1; /* over current polarity if oc enabled
+*/
 	unsigned int evdo:1; /* set external vbus divider option */  };

diff --git a/drivers/usb/chipidea/usbmisc_imx.c

b/drivers/usb/chipidea/usbmisc_imx.c
index ab8b027..193dbe4 100644

--- a/drivers/usb/chipidea/usbmisc_imx.c
+++ b/drivers/usb/chipidea/usbmisc_imx.c

@@ -56,6 +56,7 @@

 #define MX6_BM_NON_BURST_SETTING	BIT(1)
 #define MX6_BM_OVER_CUR_DIS		BIT(7)
+#define MX6_BM_OVER_CUR_POLARITY	BIT(8)
 #define MX6_BM_WAKEUP_ENABLE		BIT(10)
 #define MX6_BM_ID_WAKEUP		BIT(16)
 #define MX6_BM_VBUS_WAKEUP		BIT(17)

@@ -266,11 +267,18 @@ static int usbmisc_imx6q_init(struct

imx_usbmisc_data *data)

 	spin_lock_irqsave(&usbmisc->lock, flags);

+	reg = readl(usbmisc->base + data->index * 4);
 	if (data->disable_oc) {
-		reg = readl(usbmisc->base + data->index * 4);
-		writel(reg | MX6_BM_OVER_CUR_DIS,
-			usbmisc->base + data->index * 4);
+		reg |= MX6_BM_OVER_CUR_DIS;
+	} else if (data->oc_polarity == 1) {
+		/* High active */
+		reg &= ~(MX6_BM_OVER_CUR_DIS | MX6_BM_OVER_CUR_POLARITY);
+	} else {
+		/* Low active */
+		reg &= ~MX6_BM_OVER_CUR_DIS;
+		reg |= MX6_BM_OVER_CUR_POLARITY;
 	}
+	writel(reg, usbmisc->base + data->index * 4);

 	/* SoC non-burst setting */
 	reg = readl(usbmisc->base + data->index * 4); @@ -365,10 +373,18 @@
static int usbmisc_imx7d_init(struct imx_usbmisc_data *data)
 		return -EINVAL;

 	spin_lock_irqsave(&usbmisc->lock, flags);
+	reg = readl(usbmisc->base);
 	if (data->disable_oc) {
-		reg = readl(usbmisc->base);
-		writel(reg | MX6_BM_OVER_CUR_DIS, usbmisc->base);
+		reg |= MX6_BM_OVER_CUR_DIS;
+	} else if (data->oc_polarity == 1) {
+		/* High active */
+		reg &= ~(MX6_BM_OVER_CUR_DIS | MX6_BM_OVER_CUR_POLARITY);
+	} else {
+		/* Low active */
+		reg &= ~MX6_BM_OVER_CUR_DIS;
+		reg |= MX6_BM_OVER_CUR_POLARITY;
 	}
+	writel(reg, usbmisc->base);

 	reg = readl(usbmisc->base + MX7D_USBNC_USB_CTRL2);
 	reg &= ~MX7D_USB_VBUS_WAKEUP_SOURCE_MASK;

@@ -492,6 +508,10 @@ static const struct of_device_id

usbmisc_imx_dt_ids[] = {

quoted

 		.compatible = "fsl,imx6ul-usbmisc",
 		.data = &imx6sx_usbmisc_ops,
 	},
+	{
+		.compatible = "fsl,imx7d-usbmisc",
+		.data = &imx7d_usbmisc_ops,
+	},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, usbmisc_imx_dt_ids);
--
1.9.1


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--

Best Regards,
Peter Chen

-- 

Best Regards,
Peter Chen