RE: [PATCH 3/8] Bluetooth: btnxpuart: Add M.2 Bluetooth device support using pwrseq

[Sherry Sun]

> Subject: RE: [PATCH 3/8] Bluetooth: btnxpuart: Add M.2 Bluetooth device
> support using pwrseq
> 
> > On Thu, Jun 18, 2026 at 06:10:42PM +0800, Sherry Sun (OSS) wrote:
> > > From: Sherry Sun <sherry.sun@xxxxxxx>
> > >
> > > Power supply to the M.2 Bluetooth device attached to the host using
> > > M.2 connector is controlled using the 'uart' pwrseq device. So add
> > > support for getting the pwrseq device if the OF graph link is present.
> > > Once obtained, the existing pwrseq APIs can be used to control the
> > > power supplies of the
> > > M.2 card.
> > >
> > > Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
> > > ---
> > >  drivers/bluetooth/btnxpuart.c | 33
> > > ++++++++++++++++++++++++++++++---
> > >  1 file changed, 30 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/bluetooth/btnxpuart.c
> > > b/drivers/bluetooth/btnxpuart.c index e7036a48ce48..1aa8972f0dab
> > > 100644
> > > --- a/drivers/bluetooth/btnxpuart.c
> > > +++ b/drivers/bluetooth/btnxpuart.c
> > > @@ -9,6 +9,8 @@
> > >
> > >  #include <linux/serdev.h>
> > >  #include <linux/of.h>
> > > +#include <linux/of_graph.h>
> > > +#include <linux/pwrseq/consumer.h>
> > >  #include <linux/skbuff.h>
> > >  #include <linux/unaligned.h>
> > >  #include <linux/firmware.h>
> > > @@ -211,6 +213,7 @@ struct btnxpuart_dev {
> > >
> > >  	struct ps_data psdata;
> > >  	struct btnxpuart_data *nxp_data;
> > > +	struct pwrseq_desc *pwrseq;
> > >  	struct reset_control *pdn;
> > >  	struct hci_uart hu;
> > >  };
> > > @@ -1866,11 +1869,27 @@ static int nxp_serdev_probe(struct
> > serdev_device *serdev)
> > >  		return err;
> > >  	}
> > >
> > > +	if (of_graph_is_present(dev_of_node(&serdev->ctrl->dev))) {
> > > +		struct pwrseq_desc *pwrseq;
> > > +
> > > +		pwrseq = devm_pwrseq_get(&serdev->ctrl->dev, "uart");
> > > +		if (IS_ERR(pwrseq))
> > > +			return PTR_ERR(pwrseq);
> > > +
> > > +		nxpdev->pwrseq = pwrseq;
> > > +		err = pwrseq_power_on(pwrseq);
> > > +		if (err) {
> > > +			dev_err(&serdev->dev, "Failed to power on
> > pwrseq\n");
> > > +			return err;
> > > +		}
> >
> > Can you provide helper function like devm clk get and enabled?
> > like devm_pwrsq_get_on()
> >
> > So simple below error handle.
> 
> Ok, will try.
> 

Hi Frank,

I re-checked the devm_pwrseq_get() and found that it has already
registered devm_pwrseq_put → pwrseq_put(), and pwrseq_put()
calls pwrseq_power_off() when desc->powered_on == true.

The unwind is fully automatic. So no extra cleanup action is needed
for power-off, also no need for the helper function like
devm_pwrsq_get_on() here, I will directly delete the power_off
error handling in V2. 

Best Regards
Sherry
> 
> >
> > > +	}
> > > +
> > >  	/* Initialize and register HCI device */
> > >  	hdev = hci_alloc_dev();
> > >  	if (!hdev) {
> > >  		dev_err(&serdev->dev, "Can't allocate HCI device\n");
> > > -		return -ENOMEM;
> > > +		err = -ENOMEM;
> > > +		goto err_pwrseq_power_off;
> > >  	}
> > >
> > >  	reset_control_deassert(nxpdev->pdn);
> > > @@ -1903,11 +1922,14 @@ static int nxp_serdev_probe(struct
> > > serdev_device *serdev)
> > >
> > >  	if (hci_register_dev(hdev) < 0) {
> > >  		dev_err(&serdev->dev, "Can't register HCI device\n");
> > > +		err = -ENODEV;
> > >  		goto probe_fail;
> > >  	}
> > >
> > > -	if (ps_setup(hdev))
> > > +	if (ps_setup(hdev)) {
> > > +		err = -ENODEV;
> > >  		goto probe_fail;
> > > +	}
> > >
> > >  	hci_devcd_register(hdev, nxp_coredump, nxp_coredump_hdr,
> > >  			   nxp_coredump_notify);
> > > @@ -1917,7 +1939,10 @@ static int nxp_serdev_probe(struct
> > > serdev_device *serdev)
> > >  probe_fail:
> > >  	reset_control_assert(nxpdev->pdn);
> > >  	hci_free_dev(hdev);
> > > -	return -ENODEV;
> > > +err_pwrseq_power_off:
> > > +	if (nxpdev->pwrseq)
> > > +		pwrseq_power_off(nxpdev->pwrseq);
> > > +	return err;
> > >  }
> > >
> > >  static void nxp_serdev_remove(struct serdev_device *serdev) @@
> > > -1944,6 +1969,8 @@ static void nxp_serdev_remove(struct
> > > serdev_device
> > *serdev)
> > >  	ps_cleanup(nxpdev);
> > >  	hci_unregister_dev(hdev);
> > >  	reset_control_assert(nxpdev->pdn);
> > > +	if (nxpdev->pwrseq)
> > > +		pwrseq_power_off(nxpdev->pwrseq);
> > >  	hci_free_dev(hdev);
> > >  }
> > >
> > > --
> > > 2.50.1
> > >
> > >