Hi!

> > > > Here's v4 set of n_gsm serdev support patches, and the related protocol
> > > > driver for the modem found on Motorola Mapphone phones and tablets
> > > > like droid4.
> > > > 
> > > > This series only adds basic character device support for the serdev
> > > > driver. Other serdev consumer drivers for specific devices will be
> > > > posted separately.
> > > 
> > > I'm still missing an architectural (design) overview here -- reviewer
> > > time is a scarce resource.
> > > 
> > > I also suggested earlier that you include, at least as an RFC, one or
> > > more of your child-device drivers so that we can see how this ends up
> > > being used in the end (including an example devicetree).
> > 
> > Note that this is useful on its own: we have ofonod running on the top
> > of this doing calls and SMSes.
> 
> Yup.
> 
> > Tony: I know you have drivers depending on this somewhere (audio
> > routing and GPS), but I can't find them. It is not droid4-pending-v5.6
> > AFAICT. Do you have a pointer / could you publish them somewhere?
> 
> Hmm they should be there in droid4-pending-v5.6 branch [0]:
> 
> $ git log --abbrev=12 --pretty=format:"%h (\"%s\")" \
> 	v5.6..droid4-pending-v5.6 | grep -i -e gsm -e mot -e mdm
> e09590a260a4 ("mfd: motmdm: Fix oops on unload of motorola-mdm")
> f9252f9ff6bd ("mfd: motmdm: Revert bad list change")
> d733dcaf4416 ("mfd: motmdm: Fix issue with receiving data before ddata is set")
> 452d2b5d4c95 ("n_gsm: Build fixes for make randconfig build")
> 6882b27ea92a ("phy: mapphone-mdm6600: Fix write timeouts with shorter GPIO toggle interval")
> 58ff58c4b520 ("mfd: motmdm: Add basic DTMF support")
> e92b6f30e5ae ("ASoC: audio-graph-card: Add audio mixer for motorold mdm6600")
> c2caea5767d5 ("gnss: mot-mdm6600: Add support for Motorola Mapphone MDM6600 modem")
> a5f73b7b06f6 ("mfd: motmdm: Add Motorola TS 27.010 serdev driver for devices like droid4")
> 6c311d5aeb0a ("dt-bindings: mfd: motmdm: Add binding for motorola-mdm")
> cd02274b920e ("tty: n_gsm: Add support for serdev drivers")
> a73a48321c98 ("phy: mapphone-mdm6600: Fix timeouts by adding wake-up handling")

Thanks for pointers, I was lost in all the git trees. Port is not
quite trivial :-(.

    I tried to port GPS and codec support over to new version of base
    patches, but I get oops when I try to open the GPS:

Best regards,
								Pavel
    
    [  182.877014] bfe0: 00000005 bed23af8 b6f279cf b6eb46f6 00070030
    bed23ea7 00000000 00000000
    [  182.901672] [<c06e7ba8>] (motmdm_gnss_open) from [<c06e71d4>]
    (gnss_open+0x7c/0xb0)
    [  182.901672] [<c06e71d4>] (gnss_open) from [<c0221fe0>]
    (chrdev_open+0x9c/0x194)
    [  182.901672] [<c0221fe0>] (chrdev_open) from [<c0219524>]
    (do_dentry_open+0x21c/0x3e8)
    [  182.901672] [<c0219524>] (do_dentry_open) from [<c022b424>]
    (path_openat+0x8b0/0xc1c)
    [  182.901672] [<c022b424>] (path_openat) from [<c022d0ac>]
    (do_filp_open+0x60/0xb4)
    [  182.940002] [<c022d0ac>] (do_filp_open) from [<c0219958>]
    (do_sys_openat2+0x1f0/0x2f4)
    [  182.940002] [<c0219958>] (do_sys_openat2) from [<c021ada8>]
    (do_sys_open+0x98:

diff --git a/drivers/gnss/Kconfig b/drivers/gnss/Kconfig
index 960178dfad47..13b91034e3ea 100644
--- a/drivers/gnss/Kconfig
+++ b/drivers/gnss/Kconfig
@@ -15,7 +15,6 @@ if GNSS
 
 config GNSS_MOTMDM
 	tristate "Motorola Modem TS 27.010 serdev GNSS receiver support"
-	depends on MFD_MOTMDM
 	---help---
 	  Say Y here if you have a Motorola modem using TS 27.010 line
 	  discipline for GNSS such as a Motorola Mapphone series device
diff --git a/drivers/tty/serdev/protocol/serdev-ngsm-motmdm.c b/drivers/tty/serdev/protocol/serdev-ngsm-motmdm.c
index 97eb349f5f13..f234a0cd2fb7 100644
--- a/drivers/tty/serdev/protocol/serdev-ngsm-motmdm.c
+++ b/drivers/tty/serdev/protocol/serdev-ngsm-motmdm.c
@@ -477,7 +477,7 @@ static int motmdm_send_command(struct device *dev,
 	return err;
 }
 
-static int motmdm_register_dlci(struct device *dev,
+int motmdm_register_dlci(struct device *dev,
 				struct motmdm_dlci *mot_dlci)
 {
 	struct motmdm *ddata;
@@ -522,7 +522,7 @@ static int motmdm_register_dlci(struct device *dev,
 	return err;
 }
 
-static void motmdm_unregister_dlci(struct device *dev,
+void motmdm_unregister_dlci(struct device *dev,
 				   struct motmdm_dlci *mot_dlci)
 {
 	struct motmdm *ddata;
diff --git a/include/linux/mfd/motorola-mdm.h b/include/linux/mfd/motorola-mdm.h
new file mode 100644
index 000000000000..aae61050cd34
--- /dev/null
+++ b/include/linux/mfd/motorola-mdm.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+struct gsm_serdev_dlci;
+struct kfifo;
+struct motmdm_response;
+
+enum motmdm_dlci_nr {
+	MOTMDM_DLCI1 = 1,
+	MOTMDM_DLCI2,
+	MOTMDM_DLCI3,
+	MOTMDM_DLCI4,
+	MOTMDM_DLCI5,
+	MOTMDM_DLCI6,
+	MOTMDM_DLCI7,
+	MOTMDM_DLCI8,
+	MOTMDM_DLCI9,
+	MOTMDM_DLCI10,
+	MOTMDM_DLCI11,
+	MOTMDM_DLCI12,
+	MOTMDM_DLCI13,
+	MOTMDM_DLCI14,
+	MOTMDM_DLCI15,
+};
+
+enum motmdm_state {
+	MOTMDM_STATE_IDLE = 0,
+	MOTMDM_STATE_DIAL = 1,
+	MOTMDM_STATE_ANSWERING = 2,
+	MOTMDM_STATE_CONNECTING = 3,
+	MOTMDM_STATE_INCOMING = 4,
+	MOTMDM_STATE_CONNECTED = 5,
+	MOTMDM_STATE_HANGING_UP = 6,
+	MOTMDM_STATE_DISCONNECTED = 7,
+};
+
+struct motmdm_dlci {
+	struct gsm_serdev_dlci gsm_dlci;
+	struct list_head node;
+	wait_queue_head_t read_queue;
+	struct kfifo read_fifo;
+	int line;
+	u16 id;
+	int (*send_command)(struct device *dev, struct motmdm_dlci *mot_dlci,
+			    unsigned long timeout_ms, const unsigned char *cmd,
+			    size_t cmdlen,
+			    unsigned char *rsp, size_t rsplen);
+	int (*handle_command)(struct motmdm_dlci *mot_dlci, int id,
+			      const unsigned char *buf, size_t len);
+	int (*receive_data)(struct motmdm_dlci *mot_dlci,
+			    const unsigned char *buf,
+			    size_t len);
+	int (*write)(struct device *dev, struct motmdm_dlci *mot_dlci,
+		     int cmdid, const unsigned char *buf, size_t count);
+	int (*notify)(struct motmdm_dlci *mot_dlci, enum motmdm_state);
+	struct list_head list;
+	void *privdata;		/* Do not use, internal data */
+	void *drvdata;		/* Available for consumer drivers */
+};
+
+int motmdm_register_dlci(struct device *dev, struct motmdm_dlci *mot_dlci);
+void motmdm_unregister_dlci(struct device *dev, struct motmdm_dlci *mot_dlci);
+
+static inline
+int motmdm_send_command(struct device *dev, struct motmdm_dlci *mot_dlci,
+			unsigned long timeout_ms, const unsigned char *cmd,
+			size_t cmdlen, unsigned char *rsp, size_t rsplen)
+{
+	if (mot_dlci && mot_dlci->send_command)
+		return mot_dlci->send_command(dev, mot_dlci,
+					      timeout_ms, cmd, cmdlen,
+					      rsp, rsplen);
+	else
+		return -EINVAL;
+}
+
+static inline
+int motmdm_write(struct device *dev, struct motmdm_dlci *mot_dlci,
+		 const unsigned char *buf, size_t count)
+{
+	if (mot_dlci && mot_dlci->write)
+		return mot_dlci->write(dev, mot_dlci, -1, buf, count);
+	else
+		return -EINVAL;
+}
diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index 3635fc0ab2a6..63d8d3e731ff 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -878,7 +878,6 @@ config SND_SOC_MAX9860
 
 config SND_SOC_MOTMDM
 	tristate "Motorola Modem TS 27.010 Voice Call Codec"
-	depends on MFD_MOTMDM
 	help
 	  Enable support for Motorola TS 27.010 line discipline serdev
 	  voice call codec driver for Motorola Mapphone series of devices

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