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Date:	Sat, 1 Aug 2015 00:34:53 +0900
From:	Chanwoo Choi <cwchoi00@...il.com>
To:	Roger Quadros <rogerq@...com>
Cc:	"myungjoo.ham@...sung.com" <myungjoo.ham@...sung.com>,
	Tony Lindgren <tony@...mide.com>, nm@...com,
	Felipe Balbi <balbi@...com>, linux-omap@...r.kernel.org,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Lee Jones <lee.jones@...aro.org>
Subject: Re: [PATCH v3 1/2] extcon: palmas: Support GPIO based USB ID detection

Hi Roger,

Looks good to me. But, I add one comment about mdelay.
If you modify it, you can add my acked-by message.

Acked-by: Chanwoo Choi <cw00.choi@...sung.com>

Also, You must recevie the ack message from MFD maintainer (Lee Jones).

On Fri, Jul 31, 2015 at 8:08 PM, Roger Quadros <rogerq@...com> wrote:
> Some palmas based chip variants do not have OTG based ID logic.
> For these variants we rely on GPIO based USB ID detection.
>
> These chips do have VBUS comparator for VBUS detection so we
> continue to use the old way of detecting VBUS.
>
> Signed-off-by: Roger Quadros <rogerq@...com>
> ---
>
> v3:
> -rebased on extcon-next.
> -don't use deperecated name based extcon_set_cable_state()
>
>  .../devicetree/bindings/extcon/extcon-palmas.txt   |   5 +-
>  drivers/extcon/extcon-palmas.c                     | 115 ++++++++++++++++++---
>  include/linux/mfd/palmas.h                         |   6 ++
>  3 files changed, 110 insertions(+), 16 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/extcon/extcon-palmas.txt b/Documentation/devicetree/bindings/extcon/extcon-palmas.txt
> index 45414bb..f61d5af 100644
> --- a/Documentation/devicetree/bindings/extcon/extcon-palmas.txt
> +++ b/Documentation/devicetree/bindings/extcon/extcon-palmas.txt
> @@ -10,8 +10,11 @@ Required Properties:
>
>  Optional Properties:
>   - ti,wakeup : To enable the wakeup comparator in probe
> - - ti,enable-id-detection: Perform ID detection.
> + - ti,enable-id-detection: Perform ID detection. If id-gpio is specified
> +               it performs id-detection using GPIO else using OTG core.
>   - ti,enable-vbus-detection: Perform VBUS detection.
> + - id-gpio: gpio for GPIO ID detection. See gpio binding.
> + - debounce-delay-ms: debounce delay for GPIO ID pin in milliseconds.
>
>  palmas-usb {
>         compatible = "ti,twl6035-usb", "ti,palmas-usb";
> diff --git a/drivers/extcon/extcon-palmas.c b/drivers/extcon/extcon-palmas.c
> index 8933e7e..b948984 100644
> --- a/drivers/extcon/extcon-palmas.c
> +++ b/drivers/extcon/extcon-palmas.c
> @@ -28,6 +28,9 @@
>  #include <linux/mfd/palmas.h>
>  #include <linux/of.h>
>  #include <linux/of_platform.h>
> +#include <linux/of_gpio.h>
> +
> +#define USB_GPIO_DEBOUNCE_MS   20      /* ms */
>
>  static const unsigned int palmas_extcon_cable[] = {
>         EXTCON_USB,
> @@ -118,19 +121,53 @@ static irqreturn_t palmas_id_irq_handler(int irq, void *_palmas_usb)
>         return IRQ_HANDLED;
>  }
>
> +static void palmas_gpio_id_detect(struct palmas_usb *palmas_usb)
> +{
> +       int id;
> +       struct extcon_dev *edev = palmas_usb->edev;
> +
> +       if (!palmas_usb->id_gpiod)
> +               return;
> +
> +       id = gpiod_get_value_cansleep(palmas_usb->id_gpiod);
> +
> +       if (id) {
> +               extcon_set_cable_state_(edev, EXTCON_USB_HOST, false);
> +               dev_info(palmas_usb->dev, "USB-HOST cable is detached\n");
> +       } else {
> +               extcon_set_cable_state_(edev, EXTCON_USB_HOST, true);
> +               dev_info(palmas_usb->dev, "USB-HOST cable is attached\n");
> +       }
> +}
> +
> +static irqreturn_t palmas_gpio_id_irq_handler(int irq, void *_palmas_usb)
> +{
> +       struct palmas_usb *palmas_usb = _palmas_usb;
> +
> +       if (palmas_usb->sw_debounce_ms)
> +               mdelay(palmas_usb->sw_debounce_ms);

I recommend that you use the workqueue instead of mdelay().
If using the mdelay(), CPU is busy waiting for sw_debounce_ms.
- you can refer the drivers/extcon/extcon-usb-gpio.c

> +
> +       palmas_gpio_id_detect(palmas_usb);
> +
> +       return IRQ_HANDLED;
> +}
> +
>  static void palmas_enable_irq(struct palmas_usb *palmas_usb)
>  {
>         palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>                 PALMAS_USB_VBUS_CTRL_SET,
>                 PALMAS_USB_VBUS_CTRL_SET_VBUS_ACT_COMP);
>
> -       palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
> -               PALMAS_USB_ID_CTRL_SET, PALMAS_USB_ID_CTRL_SET_ID_ACT_COMP);
> +       if (palmas_usb->enable_id_detection) {
> +               palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
> +                            PALMAS_USB_ID_CTRL_SET,
> +                            PALMAS_USB_ID_CTRL_SET_ID_ACT_COMP);
>
> -       palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
> -               PALMAS_USB_ID_INT_EN_HI_SET,
> -               PALMAS_USB_ID_INT_EN_HI_SET_ID_GND |
> -               PALMAS_USB_ID_INT_EN_HI_SET_ID_FLOAT);
> +               palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
> +                            PALMAS_USB_ID_INT_EN_HI_SET,
> +                            PALMAS_USB_ID_INT_EN_HI_SET_ID_GND |
> +                            PALMAS_USB_ID_INT_EN_HI_SET_ID_FLOAT);
> +       }
>
>         if (palmas_usb->enable_vbus_detection)
>                 palmas_vbus_irq_handler(palmas_usb->vbus_irq, palmas_usb);
> @@ -169,20 +206,34 @@ static int palmas_usb_probe(struct platform_device *pdev)
>                         palmas_usb->wakeup = pdata->wakeup;
>         }
>
> +       palmas_usb->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id");
> +       if (IS_ERR(palmas_usb->id_gpiod)) {
> +               dev_err(&pdev->dev, "failed to get id gpio\n");
> +               return PTR_ERR(palmas_usb->id_gpiod);
> +       }
> +
> +       if (palmas_usb->enable_id_detection && palmas_usb->id_gpiod) {
> +               palmas_usb->enable_id_detection = false;
> +               palmas_usb->enable_gpio_id_detection = true;
> +       }
> +
> +       if (palmas_usb->enable_gpio_id_detection) {
> +               u32 debounce;
> +
> +               if (of_property_read_u32(node, "debounce-delay-ms", &debounce))
> +                       debounce = USB_GPIO_DEBOUNCE_MS;
> +
> +               status = gpiod_set_debounce(palmas_usb->id_gpiod,
> +                                           debounce * 1000);
> +               if (status < 0)
> +                       palmas_usb->sw_debounce_ms = debounce;
> +       }
> +
>         palmas->usb = palmas_usb;
>         palmas_usb->palmas = palmas;
>
>         palmas_usb->dev  = &pdev->dev;
>
> -       palmas_usb->id_otg_irq = regmap_irq_get_virq(palmas->irq_data,
> -                                               PALMAS_ID_OTG_IRQ);
> -       palmas_usb->id_irq = regmap_irq_get_virq(palmas->irq_data,
> -                                               PALMAS_ID_IRQ);
> -       palmas_usb->vbus_otg_irq = regmap_irq_get_virq(palmas->irq_data,
> -                                               PALMAS_VBUS_OTG_IRQ);
> -       palmas_usb->vbus_irq = regmap_irq_get_virq(palmas->irq_data,
> -                                               PALMAS_VBUS_IRQ);
> -
>         palmas_usb_wakeup(palmas, palmas_usb->wakeup);
>
>         platform_set_drvdata(pdev, palmas_usb);
> @@ -201,6 +252,10 @@ static int palmas_usb_probe(struct platform_device *pdev)
>         }
>
>         if (palmas_usb->enable_id_detection) {
> +               palmas_usb->id_otg_irq = regmap_irq_get_virq(palmas->irq_data,
> +                                                            PALMAS_ID_OTG_IRQ);
> +               palmas_usb->id_irq = regmap_irq_get_virq(palmas->irq_data,
> +                                                        PALMAS_ID_IRQ);
>                 status = devm_request_threaded_irq(palmas_usb->dev,
>                                 palmas_usb->id_irq,
>                                 NULL, palmas_id_irq_handler,
> @@ -212,9 +267,33 @@ static int palmas_usb_probe(struct platform_device *pdev)
>                                         palmas_usb->id_irq, status);
>                         return status;
>                 }
> +       } else if (palmas_usb->enable_gpio_id_detection) {
> +               palmas_usb->gpio_id_irq = gpiod_to_irq(palmas_usb->id_gpiod);
> +               if (palmas_usb->gpio_id_irq < 0) {
> +                       dev_err(&pdev->dev, "failed to get id irq\n");
> +                       return palmas_usb->gpio_id_irq;
> +               }
> +               status = devm_request_threaded_irq(&pdev->dev,
> +                                                  palmas_usb->gpio_id_irq,
> +                                                  NULL,
> +                                                  palmas_gpio_id_irq_handler,
> +                                                  IRQF_TRIGGER_RISING |
> +                                                  IRQF_TRIGGER_FALLING |
> +                                                  IRQF_ONESHOT,
> +                                                  "palmas_usb_id",
> +                                                  palmas_usb);
> +               if (status < 0) {
> +                       dev_err(&pdev->dev,
> +                               "failed to request handler for id irq\n");
> +                       return status;
> +               }
>         }
>
>         if (palmas_usb->enable_vbus_detection) {
> +               palmas_usb->vbus_otg_irq = regmap_irq_get_virq(palmas->irq_data,
> +                                                      PALMAS_VBUS_OTG_IRQ);
> +               palmas_usb->vbus_irq = regmap_irq_get_virq(palmas->irq_data,
> +                                                          PALMAS_VBUS_IRQ);
>                 status = devm_request_threaded_irq(palmas_usb->dev,
>                                 palmas_usb->vbus_irq, NULL,
>                                 palmas_vbus_irq_handler,
> @@ -229,6 +308,8 @@ static int palmas_usb_probe(struct platform_device *pdev)
>         }
>
>         palmas_enable_irq(palmas_usb);
> +       /* perform initial detection */
> +       palmas_gpio_id_detect(palmas_usb);
>         device_set_wakeup_capable(&pdev->dev, true);
>         return 0;
>  }
> @@ -243,6 +324,8 @@ static int palmas_usb_suspend(struct device *dev)
>                         enable_irq_wake(palmas_usb->vbus_irq);
>                 if (palmas_usb->enable_id_detection)
>                         enable_irq_wake(palmas_usb->id_irq);
> +               if (palmas_usb->enable_gpio_id_detection)
> +                       enable_irq_wake(palmas_usb->gpio_id_irq);
>         }
>         return 0;
>  }
> @@ -256,6 +339,8 @@ static int palmas_usb_resume(struct device *dev)
>                         disable_irq_wake(palmas_usb->vbus_irq);
>                 if (palmas_usb->enable_id_detection)
>                         disable_irq_wake(palmas_usb->id_irq);
> +               if (palmas_usb->enable_gpio_id_detection)
> +                       disable_irq_wake(palmas_usb->gpio_id_irq);
>         }
>         return 0;
>  };
> diff --git a/include/linux/mfd/palmas.h b/include/linux/mfd/palmas.h
> index bb270bd..1a202a6 100644
> --- a/include/linux/mfd/palmas.h
> +++ b/include/linux/mfd/palmas.h
> @@ -21,6 +21,7 @@
>  #include <linux/regmap.h>
>  #include <linux/regulator/driver.h>
>  #include <linux/extcon.h>
> +#include <linux/of_gpio.h>
>  #include <linux/usb/phy_companion.h>
>
>  #define PALMAS_NUM_CLIENTS             3
> @@ -551,10 +552,15 @@ struct palmas_usb {
>         int vbus_otg_irq;
>         int vbus_irq;
>
> +       int gpio_id_irq;
> +       struct gpio_desc *id_gpiod;
> +       int sw_debounce_ms;
> +
>         enum palmas_usb_state linkstat;
>         int wakeup;
>         bool enable_vbus_detection;
>         bool enable_id_detection;
> +       bool enable_gpio_id_detection;
>  };
>
>  #define comparator_to_palmas(x) container_of((x), struct palmas_usb, comparator)

Thanks,
Chanwoo Choi
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