linux-kernel - Re: [PATCH 1/3] Bluetooth: btusb: Refactor gpio reset

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Message-Id: <C17EF62B-CCCE-4C5F-90A7-247EB860608E@holtmann.org>
Date:   Mon, 25 Jan 2021 16:19:31 +0100
From:   Marcel Holtmann <marcel@...tmann.org>
To:     Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Cc:     CrosBT Upstreaming <chromeos-bluetooth-upstreaming@...omium.org>,
        Miao-chen Chou <mcchou@...omium.org>, michaelfsun@...gle.com,
        Bluetooth Kernel Mailing List 
        <linux-bluetooth@...r.kernel.org>,
        Archie Pusaka <apusaka@...omium.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] Bluetooth: btusb: Refactor gpio reset

Hi Abhishek,

> Refactor gpio reset to use a common gpio reset function.
> 
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> Reviewed-by: Miao-chen Chou <mcchou@...omium.org>
> ---
> 
> drivers/bluetooth/btusb.c | 59 +++++++++++++--------------------------
> 1 file changed, 19 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> index b14102fba6018..03341e6cbf3ed 100644
> --- a/drivers/bluetooth/btusb.c
> +++ b/drivers/bluetooth/btusb.c
> @@ -547,6 +547,7 @@ struct btusb_data {
> 	struct usb_endpoint_descriptor *diag_rx_ep;
> 
> 	struct gpio_desc *reset_gpio;
> +	unsigned int reset_duration_ms;
> 
> 	__u8 cmdreq_type;
> 	__u8 cmdreq;
> @@ -566,15 +567,21 @@ struct btusb_data {
> 	unsigned cmd_timeout_cnt;
> };
> 
> -static void btusb_intel_cmd_timeout(struct hci_dev *hdev)
> +static void btusb_toggle_gpio(struct gpio_desc *desc, unsigned int duration)
> +{
> +	gpiod_set_value_cansleep(desc, 1);
> +	msleep(duration);
> +	gpiod_set_value_cansleep(desc, 0);
> +}
> +
> +static void btusb_gpio_cmd_timeout(struct hci_dev *hdev)
> {
> 	struct btusb_data *data = hci_get_drvdata(hdev);
> -	struct gpio_desc *reset_gpio = data->reset_gpio;
> 
> 	if (++data->cmd_timeout_cnt < 5)
> 		return;
> 
> -	if (!reset_gpio) {
> +	if (!data->reset_gpio) {
> 		bt_dev_err(hdev, "No way to reset. Ignoring and continuing");
> 		return;
> 	}
> @@ -592,39 +599,7 @@ static void btusb_intel_cmd_timeout(struct hci_dev *hdev)
> 	}
> 
> 	bt_dev_err(hdev, "Initiating HW reset via gpio");
> -	gpiod_set_value_cansleep(reset_gpio, 1);
> -	msleep(100);
> -	gpiod_set_value_cansleep(reset_gpio, 0);
> -}
> -
> -static void btusb_rtl_cmd_timeout(struct hci_dev *hdev)
> -{
> -	struct btusb_data *data = hci_get_drvdata(hdev);
> -	struct gpio_desc *reset_gpio = data->reset_gpio;
> -
> -	if (++data->cmd_timeout_cnt < 5)
> -		return;
> -
> -	if (!reset_gpio) {
> -		bt_dev_err(hdev, "No gpio to reset Realtek device, ignoring");
> -		return;
> -	}
> -
> -	/* Toggle the hard reset line. The Realtek device is going to
> -	 * yank itself off the USB and then replug. The cleanup is handled
> -	 * correctly on the way out (standard USB disconnect), and the new
> -	 * device is detected cleanly and bound to the driver again like
> -	 * it should be.
> -	 */
> -	if (test_and_set_bit(BTUSB_HW_RESET_ACTIVE, &data->flags)) {
> -		bt_dev_err(hdev, "last reset failed? Not resetting again");
> -		return;
> -	}
> -
> -	bt_dev_err(hdev, "Reset Realtek device via gpio");
> -	gpiod_set_value_cansleep(reset_gpio, 1);
> -	msleep(200);
> -	gpiod_set_value_cansleep(reset_gpio, 0);
> +	btusb_toggle_gpio(data->reset_gpio, data->reset_duration_ms);
> }

You need to explain why this patch is correct. You are removing more code here. And there is an extra check in case of Realtek and a large comment.

Regards

Marcel