[v3,10/12] hikey960: Support usb functionality of Hikey960

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Yu Chen]

This driver handles usb hub power on and typeC port event of HiKey960 board:
1)DP&DM switching between usb hub and typeC port base on typeC port
state
2)Control power of usb hub on Hikey960
3)Control vbus of typeC port

Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Binghui Wang <wangbinghui@hisilicon.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Yu Chen <chenyu56@huawei.com>
---
v1:
* Using gpiod API with the gpios.
* Removing registering usb role switch.
* Registering usb role switch notifier.
v2:
* Fix license declaration.
* Add configuration of  gpio direction.
* Remove some log print.
v3:
* Remove property of "typec_vbus_enable_val".
* Remove gpiod_direction_output and set initial value of gpio by devm_gpiod_get.
---
---
 drivers/misc/Kconfig          |   6 ++
 drivers/misc/Makefile         |   1 +
 drivers/misc/hisi_hikey_usb.c | 167 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 174 insertions(+)
 create mode 100644 drivers/misc/hisi_hikey_usb.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index f417b06e11c5..8d8b717759e2 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -521,6 +521,12 @@ config PVPANIC
 	  a paravirtualized device provided by QEMU; it lets a virtual machine
 	  (guest) communicate panic events to the host.
 
+config HISI_HIKEY_USB
+	tristate "USB functionality of HiSilicon Hikey Platform"
+	depends on OF && GPIOLIB
+	help
+	  If you say yes here you get support for usb functionality of HiSilicon Hikey Platform.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index e39ccbbc1b3a..dc8892b13a1a 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -59,3 +59,4 @@ obj-$(CONFIG_PCI_ENDPOINT_TEST)	+= pci_endpoint_test.o
 obj-$(CONFIG_OCXL)		+= ocxl/
 obj-y				+= cardreader/
 obj-$(CONFIG_PVPANIC)   	+= pvpanic.o
+obj-$(CONFIG_HISI_HIKEY_USB)	+= hisi_hikey_usb.o
diff --git a/drivers/misc/hisi_hikey_usb.c b/drivers/misc/hisi_hikey_usb.c
new file mode 100644
index 000000000000..85d6fee468c0
--- /dev/null
+++ b/drivers/misc/hisi_hikey_usb.c
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Support for usb functionality of Hikey series boards
+ * based on Hisilicon Kirin Soc.
+ *
+ * Copyright (C) 2017-2018 Hilisicon Electronics Co., Ltd.
+ *		http://www.huawei.com
+ *
+ * Authors: Yu Chen <chenyu56@huawei.com>
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/usb/role.h>
+
+#define DEVICE_DRIVER_NAME "hisi_hikey_usb"
+
+#define HUB_VBUS_POWER_ON 1
+#define HUB_VBUS_POWER_OFF 0
+#define USB_SWITCH_TO_HUB 1
+#define USB_SWITCH_TO_TYPEC 0
+#define TYPEC_VBUS_POWER_ON 1
+#define TYPEC_VBUS_POWER_OFF 0
+
+struct hisi_hikey_usb {
+	struct gpio_desc *otg_switch;
+	struct gpio_desc *typec_vbus;
+	struct gpio_desc *hub_vbus;
+
+	struct usb_role_switch *role_sw;
+	struct notifier_block nb;
+};
+
+static void hub_power_ctrl(struct hisi_hikey_usb *hisi_hikey_usb, int value)
+{
+	gpiod_set_value_cansleep(hisi_hikey_usb->hub_vbus, value);
+}
+
+static void usb_switch_ctrl(struct hisi_hikey_usb *hisi_hikey_usb,
+		int switch_to)
+{
+	gpiod_set_value_cansleep(hisi_hikey_usb->otg_switch, switch_to);
+}
+
+static void usb_typec_power_ctrl(struct hisi_hikey_usb *hisi_hikey_usb,
+		int value)
+{
+	gpiod_set_value_cansleep(hisi_hikey_usb->typec_vbus, value);
+}
+
+static int hisi_hikey_role_switch(struct notifier_block *nb,
+			unsigned long state, void *data)
+{
+	struct hisi_hikey_usb *hisi_hikey_usb;
+
+	hisi_hikey_usb = container_of(nb, struct hisi_hikey_usb, nb);
+
+	switch (state) {
+	case USB_ROLE_NONE:
+		usb_typec_power_ctrl(hisi_hikey_usb, TYPEC_VBUS_POWER_OFF);
+		usb_switch_ctrl(hisi_hikey_usb, USB_SWITCH_TO_HUB);
+		hub_power_ctrl(hisi_hikey_usb, HUB_VBUS_POWER_ON);
+		break;
+	case USB_ROLE_HOST:
+		usb_switch_ctrl(hisi_hikey_usb, USB_SWITCH_TO_TYPEC);
+		usb_typec_power_ctrl(hisi_hikey_usb, TYPEC_VBUS_POWER_ON);
+		break;
+	case USB_ROLE_DEVICE:
+		hub_power_ctrl(hisi_hikey_usb, HUB_VBUS_POWER_OFF);
+		usb_typec_power_ctrl(hisi_hikey_usb, TYPEC_VBUS_POWER_OFF);
+		usb_switch_ctrl(hisi_hikey_usb, USB_SWITCH_TO_TYPEC);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int hisi_hikey_usb_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *root = dev->of_node;
+	struct hisi_hikey_usb *hisi_hikey_usb;
+	int ret;
+
+	hisi_hikey_usb = devm_kzalloc(dev, sizeof(*hisi_hikey_usb), GFP_KERNEL);
+	if (!hisi_hikey_usb)
+		return -ENOMEM;
+
+	hisi_hikey_usb->nb.notifier_call = hisi_hikey_role_switch;
+
+	hisi_hikey_usb->typec_vbus = devm_gpiod_get(dev, "typec-vbus",
+			GPIOD_OUT_LOW);
+	if (!hisi_hikey_usb->typec_vbus)
+		return -ENOENT;
+	else if (IS_ERR(hisi_hikey_usb->typec_vbus))
+		return PTR_ERR(hisi_hikey_usb->typec_vbus);
+
+	hisi_hikey_usb->otg_switch = devm_gpiod_get(dev, "otg-switch",
+			GPIOD_OUT_HIGH);
+	if (!hisi_hikey_usb->otg_switch)
+		return -ENOENT;
+	else if (IS_ERR(hisi_hikey_usb->otg_switch))
+		return PTR_ERR(hisi_hikey_usb->otg_switch);
+
+	/* hub-vdd33-en is optional */
+	hisi_hikey_usb->hub_vbus = devm_gpiod_get(dev, "hub-vdd33-en",
+			GPIOD_OUT_HIGH);
+	if (IS_ERR(hisi_hikey_usb->hub_vbus))
+		return PTR_ERR(hisi_hikey_usb->hub_vbus);
+
+	hisi_hikey_usb->role_sw = usb_role_switch_get(dev);
+	if (!hisi_hikey_usb->role_sw)
+		return -EPROBE_DEFER;
+	else if (IS_ERR(hisi_hikey_usb->role_sw))
+		return PTR_ERR(hisi_hikey_usb->role_sw);
+
+	ret = usb_role_switch_register_notifier(hisi_hikey_usb->role_sw,
+			&hisi_hikey_usb->nb);
+	if (ret) {
+		usb_role_switch_put(hisi_hikey_usb->role_sw);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, hisi_hikey_usb);
+
+	return 0;
+}
+
+static int  hisi_hikey_usb_remove(struct platform_device *pdev)
+{
+	struct hisi_hikey_usb *hisi_hikey_usb = platform_get_drvdata(pdev);
+
+	usb_role_switch_unregister_notifier(hisi_hikey_usb->role_sw,
+			&hisi_hikey_usb->nb);
+
+	usb_role_switch_put(hisi_hikey_usb->role_sw);
+
+	return 0;
+}
+
+static const struct of_device_id id_table_hisi_hikey_usb[] = {
+	{.compatible = "hisilicon,gpio_hubv1"},
+	{.compatible = "hisilicon,hikey960_usb"},
+	{}
+};
+
+static struct platform_driver hisi_hikey_usb_driver = {
+	.probe = hisi_hikey_usb_probe,
+	.remove = hisi_hikey_usb_remove,
+	.driver = {
+		.name = DEVICE_DRIVER_NAME,
+		.of_match_table = id_table_hisi_hikey_usb,
+	},
+};
+
+module_platform_driver(hisi_hikey_usb_driver);
+
+MODULE_AUTHOR("Yu Chen <chenyu56@huawei.com>");
+MODULE_DESCRIPTION("Driver Support for USB functionality of Hikey");
+MODULE_LICENSE("GPL v2");

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Andy Shevchenko]

On Sat, Mar 2, 2019 at 11:05 AM Yu Chen <chenyu56@huawei.com> wrote:
>
> This driver handles usb hub power on and typeC port event of HiKey960 board:
> 1)DP&DM switching between usb hub and typeC port base on typeC port
> state
> 2)Control power of usb hub on Hikey960
> 3)Control vbus of typeC port

> +config HISI_HIKEY_USB
> +       tristate "USB functionality of HiSilicon Hikey Platform"
> +       depends on OF && GPIOLIB
> +       help
> +         If you say yes here you get support for usb functionality of HiSilicon Hikey Platform.

> +#include <linux/of.h>

It's hard to see why this have
depends on OF followed by above header inclusion.

> +       hisi_hikey_usb->typec_vbus = devm_gpiod_get(dev, "typec-vbus",
> +                       GPIOD_OUT_LOW);

> +       if (!hisi_hikey_usb->typec_vbus)
> +               return -ENOENT;

Hmm... Is it possible to get NULL pointer from gpiod_get() at all?

> +       if (!hisi_hikey_usb->otg_switch)
> +               return -ENOENT;

Ditto.

> +       /* hub-vdd33-en is optional */
> +       hisi_hikey_usb->hub_vbus = devm_gpiod_get(dev, "hub-vdd33-en",
> +                       GPIOD_OUT_HIGH);

devm_gpio_get_optional() if it's indeed optional.

> +       hisi_hikey_usb->role_sw = usb_role_switch_get(dev);
> +       if (!hisi_hikey_usb->role_sw)
> +               return -EPROBE_DEFER;

> +       else if (IS_ERR(hisi_hikey_usb->role_sw))

Redundant 'else'

> +               return PTR_ERR(hisi_hikey_usb->role_sw);

> +static const struct of_device_id id_table_hisi_hikey_usb[] = {
> +       {.compatible = "hisilicon,gpio_hubv1"},
> +       {.compatible = "hisilicon,hikey960_usb"},
> +       {}
> +};

MODULE_DEVICE_TABLE()?

[v3,10/12] hikey960: Support usb functionality of Hikey960

[John Stultz]

On Sat, Mar 2, 2019 at 4:05 AM Yu Chen <chenyu56@huawei.com> wrote:
> +static int hisi_hikey_usb_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct device_node *root = dev->of_node;

Minor nit: root is unused and generates build warnings.

thanks
-john

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Yu Chen]

On 2019/3/4 4:17, John Stultz wrote:
> On Sat, Mar 2, 2019 at 4:05 AM Yu Chen <chenyu56@huawei.com> wrote:
>> +static int hisi_hikey_usb_probe(struct platform_device *pdev)
>> +{
>> +       struct device *dev = &pdev->dev;
>> +       struct device_node *root = dev->of_node;
> 
> Minor nit: root is unused and generates build warnings.
> 
OK. Thanks!

> thanks
> -john
> 
> .
> 

Thanks
Yu Chen

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Chunfeng Yun]

hi,
On Sat, 2019-03-02 at 17:05 +0800, Yu Chen wrote:
> This driver handles usb hub power on and typeC port event of HiKey960 board:
> 1)DP&DM switching between usb hub and typeC port base on typeC port
> state
> 2)Control power of usb hub on Hikey960
> 3)Control vbus of typeC port
> 
> Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Binghui Wang <wangbinghui@hisilicon.com>
> Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Signed-off-by: Yu Chen <chenyu56@huawei.com>
> ---
> v1:
> * Using gpiod API with the gpios.
> * Removing registering usb role switch.
> * Registering usb role switch notifier.
> v2:
> * Fix license declaration.
> * Add configuration of  gpio direction.
> * Remove some log print.
> v3:
> * Remove property of "typec_vbus_enable_val".
> * Remove gpiod_direction_output and set initial value of gpio by devm_gpiod_get.
> ---
> ---
>  drivers/misc/Kconfig          |   6 ++
>  drivers/misc/Makefile         |   1 +
>  drivers/misc/hisi_hikey_usb.c | 167 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 174 insertions(+)
>  create mode 100644 drivers/misc/hisi_hikey_usb.c
> 
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index f417b06e11c5..8d8b717759e2 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -521,6 +521,12 @@ config PVPANIC
>  	  a paravirtualized device provided by QEMU; it lets a virtual machine
>  	  (guest) communicate panic events to the host.
>  
> +config HISI_HIKEY_USB
> +	tristate "USB functionality of HiSilicon Hikey Platform"
> +	depends on OF && GPIOLIB
> +	help
> +	  If you say yes here you get support for usb functionality of HiSilicon Hikey Platform.
> +
>  source "drivers/misc/c2port/Kconfig"
>  source "drivers/misc/eeprom/Kconfig"
>  source "drivers/misc/cb710/Kconfig"
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index e39ccbbc1b3a..dc8892b13a1a 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -59,3 +59,4 @@ obj-$(CONFIG_PCI_ENDPOINT_TEST)	+= pci_endpoint_test.o
>  obj-$(CONFIG_OCXL)		+= ocxl/
>  obj-y				+= cardreader/
>  obj-$(CONFIG_PVPANIC)   	+= pvpanic.o
> +obj-$(CONFIG_HISI_HIKEY_USB)	+= hisi_hikey_usb.o
> diff --git a/drivers/misc/hisi_hikey_usb.c b/drivers/misc/hisi_hikey_usb.c
> new file mode 100644
> index 000000000000..85d6fee468c0
> --- /dev/null
> +++ b/drivers/misc/hisi_hikey_usb.c
> @@ -0,0 +1,167 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Support for usb functionality of Hikey series boards
> + * based on Hisilicon Kirin Soc.
> + *
> + * Copyright (C) 2017-2018 Hilisicon Electronics Co., Ltd.
> + *		http://www.huawei.com
> + *
> + * Authors: Yu Chen <chenyu56@huawei.com>
> + */
> +
> +#include <linux/gpio/consumer.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/notifier.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/usb/role.h>
> +
> +#define DEVICE_DRIVER_NAME "hisi_hikey_usb"
> +
> +#define HUB_VBUS_POWER_ON 1
> +#define HUB_VBUS_POWER_OFF 0
> +#define USB_SWITCH_TO_HUB 1
> +#define USB_SWITCH_TO_TYPEC 0
> +#define TYPEC_VBUS_POWER_ON 1
> +#define TYPEC_VBUS_POWER_OFF 0
> +
> +struct hisi_hikey_usb {
> +	struct gpio_desc *otg_switch;
> +	struct gpio_desc *typec_vbus;
> +	struct gpio_desc *hub_vbus;
> +
> +	struct usb_role_switch *role_sw;
> +	struct notifier_block nb;
> +};
> +
> +static void hub_power_ctrl(struct hisi_hikey_usb *hisi_hikey_usb, int value)
> +{
> +	gpiod_set_value_cansleep(hisi_hikey_usb->hub_vbus, value);
> +}
> +
> +static void usb_switch_ctrl(struct hisi_hikey_usb *hisi_hikey_usb,
> +		int switch_to)
> +{
> +	gpiod_set_value_cansleep(hisi_hikey_usb->otg_switch, switch_to);
> +}
> +
> +static void usb_typec_power_ctrl(struct hisi_hikey_usb *hisi_hikey_usb,
> +		int value)
> +{
> +	gpiod_set_value_cansleep(hisi_hikey_usb->typec_vbus, value);
> +}
> +
> +static int hisi_hikey_role_switch(struct notifier_block *nb,
> +			unsigned long state, void *data)
> +{
> +	struct hisi_hikey_usb *hisi_hikey_usb;
> +
> +	hisi_hikey_usb = container_of(nb, struct hisi_hikey_usb, nb);
> +
> +	switch (state) {
> +	case USB_ROLE_NONE:
> +		usb_typec_power_ctrl(hisi_hikey_usb, TYPEC_VBUS_POWER_OFF);
> +		usb_switch_ctrl(hisi_hikey_usb, USB_SWITCH_TO_HUB);
> +		hub_power_ctrl(hisi_hikey_usb, HUB_VBUS_POWER_ON);
> +		break;
> +	case USB_ROLE_HOST:
> +		usb_switch_ctrl(hisi_hikey_usb, USB_SWITCH_TO_TYPEC);
> +		usb_typec_power_ctrl(hisi_hikey_usb, TYPEC_VBUS_POWER_ON);
> +		break;
> +	case USB_ROLE_DEVICE:
> +		hub_power_ctrl(hisi_hikey_usb, HUB_VBUS_POWER_OFF);
> +		usb_typec_power_ctrl(hisi_hikey_usb, TYPEC_VBUS_POWER_OFF);
> +		usb_switch_ctrl(hisi_hikey_usb, USB_SWITCH_TO_TYPEC);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +static int hisi_hikey_usb_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *root = dev->of_node;
> +	struct hisi_hikey_usb *hisi_hikey_usb;
> +	int ret;
> +
> +	hisi_hikey_usb = devm_kzalloc(dev, sizeof(*hisi_hikey_usb), GFP_KERNEL);
> +	if (!hisi_hikey_usb)
> +		return -ENOMEM;
> +
> +	hisi_hikey_usb->nb.notifier_call = hisi_hikey_role_switch;
> +
> +	hisi_hikey_usb->typec_vbus = devm_gpiod_get(dev, "typec-vbus",
> +			GPIOD_OUT_LOW);
> +	if (!hisi_hikey_usb->typec_vbus)
> +		return -ENOENT;
> +	else if (IS_ERR(hisi_hikey_usb->typec_vbus))
> +		return PTR_ERR(hisi_hikey_usb->typec_vbus);
> +
> +	hisi_hikey_usb->otg_switch = devm_gpiod_get(dev, "otg-switch",
> +			GPIOD_OUT_HIGH);
> +	if (!hisi_hikey_usb->otg_switch)
> +		return -ENOENT;
> +	else if (IS_ERR(hisi_hikey_usb->otg_switch))
> +		return PTR_ERR(hisi_hikey_usb->otg_switch);
> +
> +	/* hub-vdd33-en is optional */
> +	hisi_hikey_usb->hub_vbus = devm_gpiod_get(dev, "hub-vdd33-en",
> +			GPIOD_OUT_HIGH);
> +	if (IS_ERR(hisi_hikey_usb->hub_vbus))
> +		return PTR_ERR(hisi_hikey_usb->hub_vbus);
> +
> +	hisi_hikey_usb->role_sw = usb_role_switch_get(dev);
> +	if (!hisi_hikey_usb->role_sw)
> +		return -EPROBE_DEFER;
Here return EPROBE_DEFFER means the related device_connection is
registered after this probe is called, right?
if not, use IS_ERR_OR_NULL then return PTR_ERR is enough
> +	else if (IS_ERR(hisi_hikey_usb->role_sw))
> +		return PTR_ERR(hisi_hikey_usb->role_sw);
> +
> +	ret = usb_role_switch_register_notifier(hisi_hikey_usb->role_sw,
> +			&hisi_hikey_usb->nb);
> +	if (ret) {
> +		usb_role_switch_put(hisi_hikey_usb->role_sw);
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, hisi_hikey_usb);
> +
> +	return 0;
> +}
> +
> +static int  hisi_hikey_usb_remove(struct platform_device *pdev)
> +{
> +	struct hisi_hikey_usb *hisi_hikey_usb = platform_get_drvdata(pdev);
> +
> +	usb_role_switch_unregister_notifier(hisi_hikey_usb->role_sw,
> +			&hisi_hikey_usb->nb);
> +
> +	usb_role_switch_put(hisi_hikey_usb->role_sw);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id id_table_hisi_hikey_usb[] = {
> +	{.compatible = "hisilicon,gpio_hubv1"},
> +	{.compatible = "hisilicon,hikey960_usb"},
> +	{}
> +};
> +
> +static struct platform_driver hisi_hikey_usb_driver = {
> +	.probe = hisi_hikey_usb_probe,
> +	.remove = hisi_hikey_usb_remove,
> +	.driver = {
> +		.name = DEVICE_DRIVER_NAME,
> +		.of_match_table = id_table_hisi_hikey_usb,
> +	},
> +};
> +
> +module_platform_driver(hisi_hikey_usb_driver);
> +
> +MODULE_AUTHOR("Yu Chen <chenyu56@huawei.com>");
> +MODULE_DESCRIPTION("Driver Support for USB functionality of Hikey");
> +MODULE_LICENSE("GPL v2");

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Yu Chen]

Hi Chunfeng Yun,

On 2019/3/4 9:47, Chunfeng Yun wrote:

>> +
>> +	hisi_hikey_usb->role_sw = usb_role_switch_get(dev);
>> +	if (!hisi_hikey_usb->role_sw)
>> +		return -EPROBE_DEFER;
> Here return EPROBE_DEFFER means the related device_connection is
> registered after this probe is called, right?
> if not, use IS_ERR_OR_NULL then return PTR_ERR is enough
Yes, the driver which register the usb_role_switch may finish probe after
this driver is probed for the first time.
>> +	else if (IS_ERR(hisi_hikey_usb->role_sw))
>> +		return PTR_ERR(hisi_hikey_usb->role_sw);
>> +
>> +	ret = usb_role_switch_register_notifier(hisi_hikey_usb->role_sw,
>> +			&hisi_hikey_usb->nb);
>> +	if (ret) {
>> +		usb_role_switch_put(hisi_hikey_usb->role_sw);
>> +		return ret;
>> +	}
>> +
>> +	platform_set_drvdata(pdev, hisi_hikey_usb);
>> +
>> +	return 0;
>> +}
>> +

> 
> 
> .
>

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Yu Chen]

Hi Andy,

On 2019/3/3 0:01, Andy Shevchenko wrote:
> On Sat, Mar 2, 2019 at 11:05 AM Yu Chen <chenyu56@huawei.com> wrote:
>>
>> This driver handles usb hub power on and typeC port event of HiKey960 board:
>> 1)DP&DM switching between usb hub and typeC port base on typeC port
>> state
>> 2)Control power of usb hub on Hikey960
>> 3)Control vbus of typeC port
> 
>> +config HISI_HIKEY_USB
>> +       tristate "USB functionality of HiSilicon Hikey Platform"
>> +       depends on OF && GPIOLIB
>> +       help
>> +         If you say yes here you get support for usb functionality of HiSilicon Hikey Platform.
> 
>> +#include <linux/of.h>
> 
> It's hard to see why this have
> depends on OF followed by above header inclusion.
> 
This driver depends on devicetree, so I add "depends on OF".
But is seems that "#include <linux/of.h>" can be removed after "of_" API
have been removed. Thanks for your reminder!
>> +       hisi_hikey_usb->typec_vbus = devm_gpiod_get(dev, "typec-vbus",
>> +                       GPIOD_OUT_LOW);
> 
>> +       if (!hisi_hikey_usb->typec_vbus)
>> +               return -ENOENT;
> 
> Hmm... Is it possible to get NULL pointer from gpiod_get() at all?
> 
>> +       if (!hisi_hikey_usb->otg_switch)
>> +               return -ENOENT;
> 
> Ditto.
> 
I check the comments of devm_gpio_get API, it will not return NULL pointer.
But is it more safe to keep the NULL checking? What is your advice?
>> +       /* hub-vdd33-en is optional */
>> +       hisi_hikey_usb->hub_vbus = devm_gpiod_get(dev, "hub-vdd33-en",
>> +                       GPIOD_OUT_HIGH);
> 
> devm_gpio_get_optional() if it's indeed optional.
> 
OK.Thanks!
>> +       hisi_hikey_usb->role_sw = usb_role_switch_get(dev);
>> +       if (!hisi_hikey_usb->role_sw)
>> +               return -EPROBE_DEFER;
> 
>> +       else if (IS_ERR(hisi_hikey_usb->role_sw))
> 
> Redundant 'else'
> 
OK.
>> +               return PTR_ERR(hisi_hikey_usb->role_sw);
> 
>> +static const struct of_device_id id_table_hisi_hikey_usb[] = {
>> +       {.compatible = "hisilicon,gpio_hubv1"},
>> +       {.compatible = "hisilicon,hikey960_usb"},
>> +       {}
>> +};
> 
> MODULE_DEVICE_TABLE()?
> 
OK.

Thanks
Yu Chen

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Andy Shevchenko]

On Mon, Mar 4, 2019 at 3:47 AM Chunfeng Yun <chunfeng.yun@mediatek.com> wrote:
> On Sat, 2019-03-02 at 17:05 +0800, Yu Chen wrote:

> > +     hisi_hikey_usb->role_sw = usb_role_switch_get(dev);
> > +     if (!hisi_hikey_usb->role_sw)
> > +             return -EPROBE_DEFER;
> Here return EPROBE_DEFFER means the related device_connection is
> registered after this probe is called, right?
> if not, use IS_ERR_OR_NULL then return PTR_ERR is enough

How enough? If return value is NULL it would be transformered to 0,
which is success return code from the ->probe() which means we will
have ->probed() and not functional device.

Am I missing something?

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Andy Shevchenko]

On Mon, Mar 4, 2019 at 4:35 AM Chen Yu <chenyu56@huawei.com> wrote:
> On 2019/3/3 0:01, Andy Shevchenko wrote:
> > On Sat, Mar 2, 2019 at 11:05 AM Yu Chen <chenyu56@huawei.com> wrote:

> >> +config HISI_HIKEY_USB
> >> +       tristate "USB functionality of HiSilicon Hikey Platform"
> >> +       depends on OF && GPIOLIB
> >> +       help
> >> +         If you say yes here you get support for usb functionality of HiSilicon Hikey Platform.
> >
> >> +#include <linux/of.h>
> >
> > It's hard to see why this have
> > depends on OF followed by above header inclusion.
> >
> This driver depends on devicetree, so I add "depends on OF".
> But is seems that "#include <linux/of.h>" can be removed after "of_" API
> have been removed. Thanks for your reminder!

So, it means that technically there is no such dependency, rather
administratively.

> >> +       hisi_hikey_usb->typec_vbus = devm_gpiod_get(dev, "typec-vbus",
> >> +                       GPIOD_OUT_LOW);
> >
> >> +       if (!hisi_hikey_usb->typec_vbus)
> >> +               return -ENOENT;
> >
> > Hmm... Is it possible to get NULL pointer from gpiod_get() at all?
> >
> >> +       if (!hisi_hikey_usb->otg_switch)
> >> +               return -ENOENT;
> >
> > Ditto.
> >
> I check the comments of devm_gpio_get API, it will not return NULL pointer.
> But is it more safe to keep the NULL checking? What is your advice?

Why do we need dead code?

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Chunfeng Yun]

hi,

On Mon, 2019-03-04 at 08:50 +0200, Andy Shevchenko wrote:
> On Mon, Mar 4, 2019 at 3:47 AM Chunfeng Yun <chunfeng.yun@mediatek.com> wrote:
> > On Sat, 2019-03-02 at 17:05 +0800, Yu Chen wrote:
> 
> > > +     hisi_hikey_usb->role_sw = usb_role_switch_get(dev);
> > > +     if (!hisi_hikey_usb->role_sw)
> > > +             return -EPROBE_DEFER;
> > Here return EPROBE_DEFFER means the related device_connection is
> > registered after this probe is called, right?
> > if not, use IS_ERR_OR_NULL then return PTR_ERR is enough
> 
> How enough? If return value is NULL it would be transformered to 0,
> which is success return code from the ->probe() which means we will
> have ->probed() and not functional device.
> 
You are right:)

> Am I missing something?
>

[v3,10/12] hikey960: Support usb functionality of Hikey960

[Yu Chen]

Hi,

On 2019/3/4 14:55, Andy Shevchenko wrote:
> On Mon, Mar 4, 2019 at 4:35 AM Chen Yu <chenyu56@huawei.com> wrote:
>> On 2019/3/3 0:01, Andy Shevchenko wrote:
>>> On Sat, Mar 2, 2019 at 11:05 AM Yu Chen <chenyu56@huawei.com> wrote:
> 
>>>> +config HISI_HIKEY_USB
>>>> +       tristate "USB functionality of HiSilicon Hikey Platform"
>>>> +       depends on OF && GPIOLIB
>>>> +       help
>>>> +         If you say yes here you get support for usb functionality of HiSilicon Hikey Platform.
>>>
>>>> +#include <linux/of.h>
>>>
>>> It's hard to see why this have
>>> depends on OF followed by above header inclusion.
>>>
>> This driver depends on devicetree, so I add "depends on OF".
>> But is seems that "#include <linux/of.h>" can be removed after "of_" API
>> have been removed. Thanks for your reminder!
> 
> So, it means that technically there is no such dependency, rather
> administratively.
> 
OK. I will remove the dependent next version.
>>>> +       hisi_hikey_usb->typec_vbus = devm_gpiod_get(dev, "typec-vbus",
>>>> +                       GPIOD_OUT_LOW);
>>>
>>>> +       if (!hisi_hikey_usb->typec_vbus)
>>>> +               return -ENOENT;
>>>
>>> Hmm... Is it possible to get NULL pointer from gpiod_get() at all?
>>>
>>>> +       if (!hisi_hikey_usb->otg_switch)
>>>> +               return -ENOENT;
>>>
>>> Ditto.
>>>
>> I check the comments of devm_gpio_get API, it will not return NULL pointer.
>> But is it more safe to keep the NULL checking? What is your advice?
> 
> Why do we need dead code?
> 
OK.I will remove it.

Thanks
Yu Chen