linux-kernel - Re: [PATCH next v2 2/2] bluetooth: btnxpuart: implement powerup sequence

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Message-ID: <CAMZdPi-4rvKfPJ2zQJ8mMOkuJ7SSXk3OePKrFYapFmdw9KZs7g@mail.gmail.com>
Date: Thu, 6 Mar 2025 16:29:58 +0100
From: Loic Poulain <loic.poulain@...aro.org>
To: Catalin Popescu <catalin.popescu@...ca-geosystems.com>
Cc: neeraj.sanjaykale@....com, marcel@...tmann.org, luiz.dentz@...il.com, 
	robh@...nel.org, krzk+dt@...nel.org, linux-bluetooth@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
	m.felsch@...gutronix.de, amitkumar.karwar@....com, conor+dt@...nel.org
Subject: Re: [PATCH next v2 2/2] bluetooth: btnxpuart: implement powerup sequence

Hi,

On Thu, 27 Feb 2025 at 11:57, Catalin Popescu
<catalin.popescu@...ca-geosystems.com> wrote:
>
> NXP bluetooth chip shares power supply and reset gpio with a WLAN
> chip. Add support for power supply and reset and enforce powerup
> sequence:
> - apply power supply
> - deassert reset/powerdown
>
> Signed-off-by: Catalin Popescu <catalin.popescu@...ca-geosystems.com>
> Reviewed-by: Neeraj Sanjay Kale <neeraj.sanjaykale@....com>
> ---
> v2:
> - rebase on linux-next tag next-20250227
> - add reviewed-by
[...]
> @@ -1522,6 +1525,7 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
>  {
>         struct hci_dev *hdev;
>         struct btnxpuart_dev *nxpdev;
> +       int err;
>
>         nxpdev = devm_kzalloc(&serdev->dev, sizeof(*nxpdev), GFP_KERNEL);
>         if (!nxpdev)
> @@ -1549,6 +1553,16 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
>
>         crc8_populate_msb(crc8_table, POLYNOMIAL8);
>
> +       nxpdev->pdn = devm_reset_control_get_optional_shared(&serdev->dev, NULL);

Maybe devm_reset_control_get_optional_shared_deasserted could be
useful here instead?




> +       if (IS_ERR(nxpdev->pdn))
> +               return PTR_ERR(nxpdev->pdn);
> +
> +       err = devm_regulator_get_enable(&serdev->dev, "vcc");
> +       if (err) {
> +               dev_err(&serdev->dev, "Failed to enable vcc regulator\n");
> +               return err;
> +       }
> +
>         /* Initialize and register HCI device */
>         hdev = hci_alloc_dev();
>         if (!hdev) {
> @@ -1556,6 +1570,8 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
>                 return -ENOMEM;
>         }
>
> +       reset_control_deassert(nxpdev->pdn);
> +
>         nxpdev->hdev = hdev;
>
>         hdev->bus = HCI_UART;
> @@ -1583,6 +1599,7 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
>         return 0;
>
>  probe_fail:
> +       reset_control_assert(nxpdev->pdn);
>         hci_free_dev(hdev);
>         return -ENODEV;
>  }
> @@ -1609,6 +1626,7 @@ static void nxp_serdev_remove(struct serdev_device *serdev)
>         }
>         ps_cleanup(nxpdev);
>         hci_unregister_dev(hdev);
> +       reset_control_assert(nxpdev->pdn);
>         hci_free_dev(hdev);
>  }
>
> --
> 2.43.0
>