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SubjectRe: [PATCH v3 3/6] usb: ohci-da8xx: disable the regulator if the overcurrent irq fired
On Tue, 9 Apr 2019, Bartosz Golaszewski wrote:

> From: Bartosz Golaszewski <bgolaszewski@baylibre.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@baylibre.com>
> ---
> drivers/usb/host/ohci-da8xx.c | 23 ++++++++++++++++++-----
> 1 file changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/host/ohci-da8xx.c b/drivers/usb/host/ohci-da8xx.c
> index 9c6d1f03b871..108fe0a1b962 100644
> --- a/drivers/usb/host/ohci-da8xx.c
> +++ b/drivers/usb/host/ohci-da8xx.c
> @@ -202,12 +202,24 @@ 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 +446,9 @@ 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;
>

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

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