[PATCH v2 0/4] USB3503: correct GPIOs polarity and update the driver

[PATCH v2 0/4] USB3503: correct GPIOs polarity and update the driver

[Marek Szyprowski]

Dear All,

A few days ago a patch for USB3503 driver has been posted (see v1 in the
changelog below), which changes the GPIO API used by the driver to the
new one (descriptor based). It turned out that this conversion broke USB
HUB operation on some boards (observed on Arndale5250).

Further analysis revealed that the existing code ignored the GPIO
polarity flags in the device tree. On the other hand the current GPIO
polarity flags used by various boards were simply incorrect, as it was
not possible to test them properly.

This patchset provides some standardisation for the GPIO polarity flags
for USB3503 chips in various DTS files and adds matching logic to USB3503
driver. For more information and rationale behind this approach, see the
thread linked as v1 below.

This patchset has been tested on the following boards:
Odroid X2, U3, XU and Arndale5250.

The patch for USB3503 driver should be merged one release later than the
DTS changes to keep the affected boards working in meantime.

Best regards
Marek Szyprowski
Samsung R&D Institute Poland


Changelog:
v2:
- added DTS fixes, assumed that RESET GPIO should be ACTIVE_LOW and all
  other GPIOs ACTIVE_HIGH
- integrated a fixup for USB3503 driver inverting the logic behind the
  RESET GPIO to match the standardised GPIOs polarity

v1: https://lore.kernel.org/linux-usb/20191205145633.187511-1-linus.walleij@linaro.org/T/
- initial version, contains only USB3503 driver patch


Patch summary:

Linus Walleij (1):
  usb: usb3503: Convert to use GPIO descriptors

Marek Szyprowski (3):
  ARM: dts: exynos: Correct USB3503 GPIOs polarity
  ARM: dts: qcom: Correct USB3503 GPIOs polarity
  ARM: dts: sun8i: a83t: Correct USB3503 GPIOs polarity

 .../boot/dts/exynos4412-odroid-common.dtsi    |  2 +-
 arch/arm/boot/dts/exynos5250-arndale.dts      |  2 +-
 arch/arm/boot/dts/exynos5410-odroidxu.dts     |  2 +-
 .../dts/qcom-mdm9615-wp8548-mangoh-green.dts  |  2 +-
 .../boot/dts/sun8i-a83t-cubietruck-plus.dts   |  2 +-
 drivers/usb/misc/usb3503.c                    | 94 +++++++------------
 include/linux/platform_data/usb3503.h         |  3 -
 7 files changed, 40 insertions(+), 67 deletions(-)

-- 
2.17.1

[PATCH v2 1/4] ARM: dts: exynos: Correct USB3503 GPIOs polarity

[Marek Szyprowski]

Current USB3503 driver ignores GPIO polarity and always operates as if the
GPIO lines were flagged as ACTIVE_HIGH. Fix the polarity for the existing
USB3503 chip applications to match the chip specification and common
convention for naming the pins. The only pin, which has to be ACTIVE_LOW
is the reset pin. The remaining are ACTIVE_HIGH. This change allows later
to fix the USB3503 driver to properly use generic GPIO bindings and read
polarity from DT.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 arch/arm/boot/dts/exynos4412-odroid-common.dtsi | 2 +-
 arch/arm/boot/dts/exynos5250-arndale.dts        | 2 +-
 arch/arm/boot/dts/exynos5410-odroidxu.dts       | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/boot/dts/exynos4412-odroid-common.dtsi b/arch/arm/boot/dts/exynos4412-odroid-common.dtsi
index ea55f377d17c..9c39e82e4ecb 100644
--- a/arch/arm/boot/dts/exynos4412-odroid-common.dtsi
+++ b/arch/arm/boot/dts/exynos4412-odroid-common.dtsi
@@ -267,7 +267,7 @@
 
 		intn-gpios = <&gpx3 0 GPIO_ACTIVE_HIGH>;
 		connect-gpios = <&gpx3 4 GPIO_ACTIVE_HIGH>;
-		reset-gpios = <&gpx3 5 GPIO_ACTIVE_HIGH>;
+		reset-gpios = <&gpx3 5 GPIO_ACTIVE_LOW>;
 		initial-mode = <1>;
 	};
 
diff --git a/arch/arm/boot/dts/exynos5250-arndale.dts b/arch/arm/boot/dts/exynos5250-arndale.dts
index d6c85efdb465..3eddf5dbcf7b 100644
--- a/arch/arm/boot/dts/exynos5250-arndale.dts
+++ b/arch/arm/boot/dts/exynos5250-arndale.dts
@@ -154,7 +154,7 @@
 		compatible = "smsc,usb3503a";
 
 		reset-gpios = <&gpx3 5 GPIO_ACTIVE_LOW>;
-		connect-gpios = <&gpd1 7 GPIO_ACTIVE_LOW>;
+		connect-gpios = <&gpd1 7 GPIO_ACTIVE_HIGH>;
 	};
 };
 
diff --git a/arch/arm/boot/dts/exynos5410-odroidxu.dts b/arch/arm/boot/dts/exynos5410-odroidxu.dts
index e0db251e253f..4f9297ae0763 100644
--- a/arch/arm/boot/dts/exynos5410-odroidxu.dts
+++ b/arch/arm/boot/dts/exynos5410-odroidxu.dts
@@ -170,7 +170,7 @@
 
 		intn-gpios = <&gpx0 7 GPIO_ACTIVE_HIGH>;
 		connect-gpios = <&gpx0 6 GPIO_ACTIVE_HIGH>;
-		reset-gpios = <&gpx1 4 GPIO_ACTIVE_HIGH>;
+		reset-gpios = <&gpx1 4 GPIO_ACTIVE_LOW>;
 		initial-mode = <1>;
 
 		clock-names = "refclk";
-- 
2.17.1

Re: [PATCH v2 1/4] ARM: dts: exynos: Correct USB3503 GPIOs polarity

[Krzysztof Kozlowski]

On Wed, Dec 11, 2019 at 03:46:35PM +0100, Marek Szyprowski wrote:
> Current USB3503 driver ignores GPIO polarity and always operates as if the
> GPIO lines were flagged as ACTIVE_HIGH. Fix the polarity for the existing
> USB3503 chip applications to match the chip specification and common
> convention for naming the pins. The only pin, which has to be ACTIVE_LOW
> is the reset pin. The remaining are ACTIVE_HIGH. This change allows later
> to fix the USB3503 driver to properly use generic GPIO bindings and read
> polarity from DT.
> 

Thanks, applied (for v5.6).

Best regards,
Krzysztof

[PATCH v2 2/4] ARM: dts: qcom: Correct USB3503 GPIOs polarity

[Marek Szyprowski]

Current USB3503 driver ignores GPIO polarity and always operates as if the
GPIO lines were flagged as ACTIVE_HIGH. Fix the polarity for the existing
USB3503 chip applications to match the chip specification and common
convention for naming the pins. The only pin, which has to be ACTIVE_LOW
is the reset pin. The remaining are ACTIVE_HIGH. This change allows later
to fix the USB3503 driver to properly use generic GPIO bindings and read
polarity from DT.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 arch/arm/boot/dts/qcom-mdm9615-wp8548-mangoh-green.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/qcom-mdm9615-wp8548-mangoh-green.dts b/arch/arm/boot/dts/qcom-mdm9615-wp8548-mangoh-green.dts
index 26160c324802..942e3a2cac35 100644
--- a/arch/arm/boot/dts/qcom-mdm9615-wp8548-mangoh-green.dts
+++ b/arch/arm/boot/dts/qcom-mdm9615-wp8548-mangoh-green.dts
@@ -143,7 +143,7 @@
 				compatible = "smsc,usb3503a";
 				reg = <0x8>;
 				connect-gpios = <&gpioext2 1 GPIO_ACTIVE_HIGH>;
-				intn-gpios = <&gpioext2 0 GPIO_ACTIVE_LOW>;
+				intn-gpios = <&gpioext2 0 GPIO_ACTIVE_HIGH>;
 				initial-mode = <1>;
 			};
 		};
-- 
2.17.1

[PATCH v2 3/4] ARM: dts: sun8i: a83t: Correct USB3503 GPIOs polarity

[Marek Szyprowski]

Current USB3503 driver ignores GPIO polarity and always operates as if the
GPIO lines were flagged as ACTIVE_HIGH. Fix the polarity for the existing
USB3503 chip applications to match the chip specification and common
convention for naming the pins. The only pin, which has to be ACTIVE_LOW
is the reset pin. The remaining are ACTIVE_HIGH. This change allows later
to fix the USB3503 driver to properly use generic GPIO bindings and read
polarity from DT.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts b/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts
index fb928503ad45..d9be511f054f 100644
--- a/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts
+++ b/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts
@@ -101,7 +101,7 @@
 		initial-mode = <1>; /* initialize in HUB mode */
 		disabled-ports = <1>;
 		intn-gpios = <&pio 7 5 GPIO_ACTIVE_HIGH>; /* PH5 */
-		reset-gpios = <&pio 4 16 GPIO_ACTIVE_HIGH>; /* PE16 */
+		reset-gpios = <&pio 4 16 GPIO_ACTIVE_LOW>; /* PE16 */
 		connect-gpios = <&pio 4 17 GPIO_ACTIVE_HIGH>; /* PE17 */
 		refclk-frequency = <19200000>;
 	};
-- 
2.17.1

[PATCH v2 4/4] usb: usb3503: Convert to use GPIO descriptors

[Marek Szyprowski]

From: Linus Walleij <linus.walleij@linaro.org>

This converts the USB3503 to pick GPIO descriptors from the
device tree instead of iteratively picking out GPIO number
references and then referencing these from the global GPIO
numberspace.

The USB3503 is only used from device tree among the in-tree
platforms. If board files would still desire to use it they can
provide machine descriptor tables.

Make sure to preserve semantics such as the reset delay
introduced by Stefan.

Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[mszyprow: invert the logic behind reset GPIO line]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/usb/misc/usb3503.c            | 94 ++++++++++-----------------
 include/linux/platform_data/usb3503.h |  3 -
 2 files changed, 35 insertions(+), 62 deletions(-)

diff --git a/drivers/usb/misc/usb3503.c b/drivers/usb/misc/usb3503.c
index 72f39a9751b5..116bd789e568 100644
--- a/drivers/usb/misc/usb3503.c
+++ b/drivers/usb/misc/usb3503.c
@@ -7,11 +7,10 @@
 
 #include <linux/clk.h>
 #include <linux/i2c.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/of_gpio.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/usb3503.h>
 #include <linux/regmap.h>
@@ -47,19 +46,19 @@ struct usb3503 {
 	struct device		*dev;
 	struct clk		*clk;
 	u8	port_off_mask;
-	int	gpio_intn;
-	int	gpio_reset;
-	int	gpio_connect;
+	struct gpio_desc	*intn;
+	struct gpio_desc 	*reset;
+	struct gpio_desc 	*connect;
 	bool	secondary_ref_clk;
 };
 
 static int usb3503_reset(struct usb3503 *hub, int state)
 {
-	if (!state && gpio_is_valid(hub->gpio_connect))
-		gpio_set_value_cansleep(hub->gpio_connect, 0);
+	if (!state && hub->connect)
+		gpiod_set_value_cansleep(hub->connect, 0);
 
-	if (gpio_is_valid(hub->gpio_reset))
-		gpio_set_value_cansleep(hub->gpio_reset, state);
+	if (hub->reset)
+		gpiod_set_value_cansleep(hub->reset, !state);
 
 	/* Wait T_HUBINIT == 4ms for hub logic to stabilize */
 	if (state)
@@ -115,8 +114,8 @@ static int usb3503_connect(struct usb3503 *hub)
 		}
 	}
 
-	if (gpio_is_valid(hub->gpio_connect))
-		gpio_set_value_cansleep(hub->gpio_connect, 1);
+	if (hub->connect)
+		gpiod_set_value_cansleep(hub->connect, 1);
 
 	hub->mode = USB3503_MODE_HUB;
 	dev_info(dev, "switched to HUB mode\n");
@@ -163,13 +162,11 @@ static int usb3503_probe(struct usb3503 *hub)
 	int err;
 	u32 mode = USB3503_MODE_HUB;
 	const u32 *property;
+	enum gpiod_flags flags;
 	int len;
 
 	if (pdata) {
 		hub->port_off_mask	= pdata->port_off_mask;
-		hub->gpio_intn		= pdata->gpio_intn;
-		hub->gpio_connect	= pdata->gpio_connect;
-		hub->gpio_reset		= pdata->gpio_reset;
 		hub->mode		= pdata->initial_mode;
 	} else if (np) {
 		u32 rate = 0;
@@ -230,59 +227,38 @@ static int usb3503_probe(struct usb3503 *hub)
 			}
 		}
 
-		hub->gpio_intn	= of_get_named_gpio(np, "intn-gpios", 0);
-		if (hub->gpio_intn == -EPROBE_DEFER)
-			return -EPROBE_DEFER;
-		hub->gpio_connect = of_get_named_gpio(np, "connect-gpios", 0);
-		if (hub->gpio_connect == -EPROBE_DEFER)
-			return -EPROBE_DEFER;
-		hub->gpio_reset = of_get_named_gpio(np, "reset-gpios", 0);
-		if (hub->gpio_reset == -EPROBE_DEFER)
-			return -EPROBE_DEFER;
 		of_property_read_u32(np, "initial-mode", &mode);
 		hub->mode = mode;
 	}
 
-	if (hub->port_off_mask && !hub->regmap)
-		dev_err(dev, "Ports disabled with no control interface\n");
-
-	if (gpio_is_valid(hub->gpio_intn)) {
-		int val = hub->secondary_ref_clk ? GPIOF_OUT_INIT_LOW :
-						   GPIOF_OUT_INIT_HIGH;
-		err = devm_gpio_request_one(dev, hub->gpio_intn, val,
-					    "usb3503 intn");
-		if (err) {
-			dev_err(dev,
-				"unable to request GPIO %d as interrupt pin (%d)\n",
-				hub->gpio_intn, err);
-			return err;
-		}
-	}
-
-	if (gpio_is_valid(hub->gpio_connect)) {
-		err = devm_gpio_request_one(dev, hub->gpio_connect,
-				GPIOF_OUT_INIT_LOW, "usb3503 connect");
-		if (err) {
-			dev_err(dev,
-				"unable to request GPIO %d as connect pin (%d)\n",
-				hub->gpio_connect, err);
-			return err;
-		}
-	}
-
-	if (gpio_is_valid(hub->gpio_reset)) {
-		err = devm_gpio_request_one(dev, hub->gpio_reset,
-				GPIOF_OUT_INIT_LOW, "usb3503 reset");
+	if (hub->secondary_ref_clk)
+		flags = GPIOD_OUT_LOW;
+	else
+		flags = GPIOD_OUT_HIGH;
+	hub->intn = devm_gpiod_get_optional(dev, "intn", flags);
+	if (IS_ERR(hub->intn))
+		return PTR_ERR(hub->intn);
+	if (hub->intn)
+		gpiod_set_consumer_name(hub->intn, "usb3503 intn");
+
+	hub->connect = devm_gpiod_get_optional(dev, "connect", GPIOD_OUT_LOW);
+	if (IS_ERR(hub->connect))
+		return PTR_ERR(hub->connect);
+	if (hub->connect)
+		gpiod_set_consumer_name(hub->connect, "usb3503 connect");
+
+	hub->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(hub->reset))
+		return PTR_ERR(hub->reset);
+	if (hub->reset) {
 		/* Datasheet defines a hardware reset to be at least 100us */
 		usleep_range(100, 10000);
-		if (err) {
-			dev_err(dev,
-				"unable to request GPIO %d as reset pin (%d)\n",
-				hub->gpio_reset, err);
-			return err;
-		}
+		gpiod_set_consumer_name(hub->reset, "usb3503 reset");
 	}
 
+	if (hub->port_off_mask && !hub->regmap)
+		dev_err(dev, "Ports disabled with no control interface\n");
+
 	usb3503_switch_mode(hub, hub->mode);
 
 	dev_info(dev, "%s: probed in %s mode\n", __func__,
diff --git a/include/linux/platform_data/usb3503.h b/include/linux/platform_data/usb3503.h
index e049d51c1353..d01ef97ddf36 100644
--- a/include/linux/platform_data/usb3503.h
+++ b/include/linux/platform_data/usb3503.h
@@ -17,9 +17,6 @@ enum usb3503_mode {
 struct usb3503_platform_data {
 	enum usb3503_mode	initial_mode;
 	u8	port_off_mask;
-	int	gpio_intn;
-	int	gpio_connect;
-	int	gpio_reset;
 };
 
 #endif
-- 
2.17.1