linux-kernel - Re: [PATCH v5 3/6] usb: ohci-da8xx: disable the regulator if the overcurrent irq fired

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Date:   Fri, 12 Apr 2019 14:38:03 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Sekhar Nori <nsekhar@...com>, Kevin Hilman <khilman@...nel.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-usb@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH v5 3/6] usb: ohci-da8xx: disable the regulator if the
 overcurrent irq fired

pt., 12 kwi 2019 o 14:36 Bartosz Golaszewski <brgl@...ev.pl> napisał(a):
>
> From: Bartosz Golaszewski <bgolaszewski@...libre.com>
>
> Historically the power supply management in this driver has been handled
> in two separate places in parallel. Device-tree users simply defined an
> appropriate regulator, while two boards with no DT support (da830-evm and
> omapl138-hawk) passed functions defined in their respective board files
> over platform data. These functions simply used legacy GPIO calls to
> watch the oc GPIO for interrupts and disable the vbus GPIO when the irq
> fires.
>
> Commit d193abf1c913 ("usb: ohci-da8xx: add vbus and overcurrent gpios")
> updated these GPIO calls to the modern API and moved them inside the
> driver.
>
> This however is not the optimal solution for the vbus GPIO which should
> be modeled as a fixed regulator that can be controlled with a GPIO.
>
> In order to keep the overcurrent protection available once we move the
> board files to using fixed regulators we need to disable the enable_reg
> regulator when the overcurrent indicator interrupt fires. Since we
> cannot call regulator_disable() from interrupt context, we need to
> switch to using a oneshot threaded interrupt.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>

Sekhar,

I forgot to include Alan's ack for v4:

Acked-by: Alan Stern <stern@...land.harvard.edu>

> ---
>  drivers/usb/host/ohci-da8xx.c | 22 +++++++++++++++++-----
>  1 file changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/host/ohci-da8xx.c b/drivers/usb/host/ohci-da8xx.c
> index 209a262b5565..f69b339d45e5 100644
> --- a/drivers/usb/host/ohci-da8xx.c
> +++ b/drivers/usb/host/ohci-da8xx.c
> @@ -202,12 +202,23 @@ static int ohci_da8xx_regulator_event(struct notifier_block *nb,
>         return 0;
>  }
>
> -static irqreturn_t ohci_da8xx_oc_handler(int irq, void *data)
> +static irqreturn_t ohci_da8xx_oc_thread(int irq, void *data)
>  {
>         struct da8xx_ohci_hcd *da8xx_ohci = data;
> +       struct device *dev = da8xx_ohci->hcd->self.controller;
> +       int ret;
>
> -       if (gpiod_get_value(da8xx_ohci->oc_gpio))
> -               gpiod_set_value(da8xx_ohci->vbus_gpio, 0);
> +       if (gpiod_get_value_cansleep(da8xx_ohci->oc_gpio)) {
> +               if (da8xx_ohci->vbus_gpio) {
> +                       gpiod_set_value_cansleep(da8xx_ohci->vbus_gpio, 0);
> +               } else if (da8xx_ohci->vbus_reg) {
> +                       ret = regulator_disable(da8xx_ohci->vbus_reg);
> +                       if (ret)
> +                               dev_err(dev,
> +                                       "Failed to disable regulator: %d\n",
> +                                       ret);
> +               }
> +       }
>
>         return IRQ_HANDLED;
>  }
> @@ -434,8 +445,9 @@ static int ohci_da8xx_probe(struct platform_device *pdev)
>                 if (oc_irq < 0)
>                         goto err;
>
> -               error = devm_request_irq(dev, oc_irq, ohci_da8xx_oc_handler,
> -                               IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> +               error = devm_request_threaded_irq(dev, oc_irq, NULL,
> +                               ohci_da8xx_oc_thread, IRQF_TRIGGER_RISING |
> +                               IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
>                                 "OHCI over-current indicator", da8xx_ohci);
>                 if (error)
>                         goto err;
> --
> 2.21.0
>