Patch "nfc: pn533: Add dev_up/dev_down hooks to phy_ops" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    nfc: pn533: Add dev_up/dev_down hooks to phy_ops

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfc-pn533-add-dev_up-dev_down-hooks-to-phy_ops.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 283c4e13f6a91ec6334d82ad36371891365ee4c9
Author: Lars Poeschel <poeschel@xxxxxxxxxxx>
Date:   Tue Oct 29 15:46:29 2019 +0100

    nfc: pn533: Add dev_up/dev_down hooks to phy_ops
    
    [ Upstream commit 0bf2840ccc6efcba82d83b224dcde19dea9f1ee3 ]
    
    This adds hooks for dev_up and dev_down to the phy_ops. They are
    optional.
    The idea is to inform the phy driver when the nfc chip is really going
    to be used. When it is not used, the phy driver can suspend it's
    interface to the nfc chip to save some power. The nfc chip is considered
    not in use before dev_up and after dev_down.
    
    Cc: Johan Hovold <johan@xxxxxxxxxx>
    Signed-off-by: Lars Poeschel <poeschel@xxxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Stable-dep-of: febccb39255f ("nfc: pn533: Add poll mod list filling check")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/nfc/pn533/pn533.c b/drivers/nfc/pn533/pn533.c
index 1e90ff17f87db..c36cd68b47eb5 100644
--- a/drivers/nfc/pn533/pn533.c
+++ b/drivers/nfc/pn533/pn533.c
@@ -2465,6 +2465,9 @@ static int pn533_dev_up(struct nfc_dev *nfc_dev)
 {
 	struct pn533 *dev = nfc_get_drvdata(nfc_dev);
 
+	if (dev->phy_ops->dev_up)
+		dev->phy_ops->dev_up(dev);
+
 	if (dev->device_type == PN533_DEVICE_PN532) {
 		int rc = pn532_sam_configuration(nfc_dev);
 
@@ -2477,7 +2480,14 @@ static int pn533_dev_up(struct nfc_dev *nfc_dev)
 
 static int pn533_dev_down(struct nfc_dev *nfc_dev)
 {
-	return pn533_rf_field(nfc_dev, 0);
+	struct pn533 *dev = nfc_get_drvdata(nfc_dev);
+	int ret;
+
+	ret = pn533_rf_field(nfc_dev, 0);
+	if (dev->phy_ops->dev_down && !ret)
+		dev->phy_ops->dev_down(dev);
+
+	return ret;
 }
 
 static struct nfc_ops pn533_nfc_ops = {
diff --git a/drivers/nfc/pn533/pn533.h b/drivers/nfc/pn533/pn533.h
index 8bf9d6ece0f50..570ee0a3e832b 100644
--- a/drivers/nfc/pn533/pn533.h
+++ b/drivers/nfc/pn533/pn533.h
@@ -207,6 +207,15 @@ struct pn533_phy_ops {
 			  struct sk_buff *out);
 	int (*send_ack)(struct pn533 *dev, gfp_t flags);
 	void (*abort_cmd)(struct pn533 *priv, gfp_t flags);
+	/*
+	 * dev_up and dev_down are optional.
+	 * They are used to inform the phy layer that the nfc chip
+	 * is going to be really used very soon. The phy layer can then
+	 * bring up it's interface to the chip and have it suspended for power
+	 * saving reasons otherwise.
+	 */
+	void (*dev_up)(struct pn533 *priv);
+	void (*dev_down)(struct pn533 *priv);
 };