[PATCH net v7 0/3] ptp: ocp: fix serial port information export

[PATCH net v7 0/3] ptp: ocp: fix serial port information export

[Vadim Fedorenko]

Starting v6.8 the serial port subsystem changed the hierarchy of devices
and symlinks are not working anymore. Previous discussion made it clear
that the idea of symlinks for tty devices was wrong by design [1].
This series implements additional attributes to expose the information
and removes symlinks for tty devices.

[1] https://lore.kernel.org/netdev/2024060503-subsonic-pupil-bbee@gregkh/

v6 -> v7:
- fix issues with applying patches
v5 -> v6:
- split conversion to array to separate patch per Jiri's feedback
- move changelog to cover letter
v4 -> v5:
- remove unused variable in ptp_ocp_tty_show
v3 -> v4:
- re-organize info printing to use ptp_ocp_tty_port_name()
- keep uintptr_t to be consistent with other code
v2 -> v3:
- replace serial ports definitions with array and enum for index
- replace pointer math with direct array access
- nit in documentation spelling
v1 -> v2:
- add Documentation/ABI changes

Vadim Fedorenko (3):
  ptp: ocp: convert serial ports to array
  ptp: ocp: adjust sysfs entries to expose tty information
  docs: ABI: update OCP TimeCard sysfs entries

 Documentation/ABI/testing/sysfs-timecard |  31 +++--
 drivers/ptp/ptp_ocp.c                    | 168 ++++++++++++++---------
 2 files changed, 119 insertions(+), 80 deletions(-)

-- 
2.43.5

[PATCH net v7 1/3] ptp: ocp: convert serial ports to array

[Vadim Fedorenko]

Simplify serial port management code by using array of ports and helpers
to get the name of the port. This change is needed to make the next
patch simplier.

Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
---
 drivers/ptp/ptp_ocp.c | 120 ++++++++++++++++++++----------------------
 1 file changed, 57 insertions(+), 63 deletions(-)

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index ee2ced88ab34..46369de8e30b 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -316,6 +316,15 @@ struct ptp_ocp_serial_port {
 #define OCP_SERIAL_LEN			6
 #define OCP_SMA_NUM			4
 
+enum {
+	PORT_GNSS,
+	PORT_GNSS2,
+	PORT_MAC, /* miniature atomic clock */
+	PORT_NMEA,
+
+	__PORT_COUNT,
+};
+
 struct ptp_ocp {
 	struct pci_dev		*pdev;
 	struct device		dev;
@@ -357,10 +366,7 @@ struct ptp_ocp {
 	struct delayed_work	sync_work;
 	int			id;
 	int			n_irqs;
-	struct ptp_ocp_serial_port	gnss_port;
-	struct ptp_ocp_serial_port	gnss2_port;
-	struct ptp_ocp_serial_port	mac_port;   /* miniature atomic clock */
-	struct ptp_ocp_serial_port	nmea_port;
+	struct ptp_ocp_serial_port	port[__PORT_COUNT];
 	bool			fw_loader;
 	u8			fw_tag;
 	u16			fw_version;
@@ -655,28 +661,28 @@ static struct ocp_resource ocp_fb_resource[] = {
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(gnss_port),
+		OCP_SERIAL_RESOURCE(port[PORT_GNSS]),
 		.offset = 0x00160000 + 0x1000, .irq_vec = 3,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 115200,
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(gnss2_port),
+		OCP_SERIAL_RESOURCE(port[PORT_GNSS2]),
 		.offset = 0x00170000 + 0x1000, .irq_vec = 4,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 115200,
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(mac_port),
+		OCP_SERIAL_RESOURCE(port[PORT_MAC]),
 		.offset = 0x00180000 + 0x1000, .irq_vec = 5,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 57600,
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(nmea_port),
+		OCP_SERIAL_RESOURCE(port[PORT_NMEA]),
 		.offset = 0x00190000 + 0x1000, .irq_vec = 10,
 	},
 	{
@@ -740,7 +746,7 @@ static struct ocp_resource ocp_art_resource[] = {
 		.offset = 0x01000000, .size = 0x10000,
 	},
 	{
-		OCP_SERIAL_RESOURCE(gnss_port),
+		OCP_SERIAL_RESOURCE(port[PORT_GNSS]),
 		.offset = 0x00160000 + 0x1000, .irq_vec = 3,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 115200,
@@ -839,7 +845,7 @@ static struct ocp_resource ocp_art_resource[] = {
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(mac_port),
+		OCP_SERIAL_RESOURCE(port[PORT_MAC]),
 		.offset = 0x00190000, .irq_vec = 7,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 9600,
@@ -950,14 +956,14 @@ static struct ocp_resource ocp_adva_resource[] = {
 		.offset = 0x00220000, .size = 0x1000,
 	},
 	{
-		OCP_SERIAL_RESOURCE(gnss_port),
+		OCP_SERIAL_RESOURCE(port[PORT_GNSS]),
 		.offset = 0x00160000 + 0x1000, .irq_vec = 3,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 9600,
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(mac_port),
+		OCP_SERIAL_RESOURCE(port[PORT_MAC]),
 		.offset = 0x00180000 + 0x1000, .irq_vec = 5,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 115200,
@@ -1649,6 +1655,15 @@ ptp_ocp_tod_gnss_name(int idx)
 	return gnss_name[idx];
 }
 
+static const char *
+ptp_ocp_tty_port_name(int idx)
+{
+	static const char * const tty_name[] = {
+		"GNSS", "GNSS2", "MAC", "NMEA"
+	};
+	return tty_name[idx];
+}
+
 struct ptp_ocp_nvmem_match_info {
 	struct ptp_ocp *bp;
 	const void * const tag;
@@ -3960,16 +3975,11 @@ ptp_ocp_summary_show(struct seq_file *s, void *data)
 	bp = dev_get_drvdata(dev);
 
 	seq_printf(s, "%7s: /dev/ptp%d\n", "PTP", ptp_clock_index(bp->ptp));
-	if (bp->gnss_port.line != -1)
-		seq_printf(s, "%7s: /dev/ttyS%d\n", "GNSS1",
-			   bp->gnss_port.line);
-	if (bp->gnss2_port.line != -1)
-		seq_printf(s, "%7s: /dev/ttyS%d\n", "GNSS2",
-			   bp->gnss2_port.line);
-	if (bp->mac_port.line != -1)
-		seq_printf(s, "%7s: /dev/ttyS%d\n", "MAC", bp->mac_port.line);
-	if (bp->nmea_port.line != -1)
-		seq_printf(s, "%7s: /dev/ttyS%d\n", "NMEA", bp->nmea_port.line);
+	for (i = 0; i < __PORT_COUNT; i++) {
+		if (bp->port[i].line != -1)
+			seq_printf(s, "%7s: /dev/ttyS%d\n", ptp_ocp_tty_port_name(i),
+				   bp->port[i].line);
+	}
 
 	memset(sma_val, 0xff, sizeof(sma_val));
 	if (bp->sma_map1) {
@@ -4279,7 +4289,7 @@ ptp_ocp_dev_release(struct device *dev)
 static int
 ptp_ocp_device_init(struct ptp_ocp *bp, struct pci_dev *pdev)
 {
-	int err;
+	int i, err;
 
 	mutex_lock(&ptp_ocp_lock);
 	err = idr_alloc(&ptp_ocp_idr, bp, 0, 0, GFP_KERNEL);
@@ -4292,10 +4302,10 @@ ptp_ocp_device_init(struct ptp_ocp *bp, struct pci_dev *pdev)
 
 	bp->ptp_info = ptp_ocp_clock_info;
 	spin_lock_init(&bp->lock);
-	bp->gnss_port.line = -1;
-	bp->gnss2_port.line = -1;
-	bp->mac_port.line = -1;
-	bp->nmea_port.line = -1;
+
+	for (i = 0; i < __PORT_COUNT; i++)
+		bp->port[i].line = -1;
+
 	bp->pdev = pdev;
 
 	device_initialize(&bp->dev);
@@ -4351,23 +4361,15 @@ ptp_ocp_complete(struct ptp_ocp *bp)
 {
 	struct pps_device *pps;
 	char buf[32];
+	int i;
 
-	if (bp->gnss_port.line != -1) {
-		sprintf(buf, "ttyS%d", bp->gnss_port.line);
-		ptp_ocp_link_child(bp, buf, "ttyGNSS");
-	}
-	if (bp->gnss2_port.line != -1) {
-		sprintf(buf, "ttyS%d", bp->gnss2_port.line);
-		ptp_ocp_link_child(bp, buf, "ttyGNSS2");
-	}
-	if (bp->mac_port.line != -1) {
-		sprintf(buf, "ttyS%d", bp->mac_port.line);
-		ptp_ocp_link_child(bp, buf, "ttyMAC");
-	}
-	if (bp->nmea_port.line != -1) {
-		sprintf(buf, "ttyS%d", bp->nmea_port.line);
-		ptp_ocp_link_child(bp, buf, "ttyNMEA");
+	for (i = 0; i < __PORT_COUNT; i++) {
+		if (bp->port[i].line != -1) {
+			sprintf(buf, "ttyS%d", bp->port[i].line);
+			ptp_ocp_link_child(bp, buf, ptp_ocp_tty_port_name(i));
+		}
 	}
+
 	sprintf(buf, "ptp%d", ptp_clock_index(bp->ptp));
 	ptp_ocp_link_child(bp, buf, "ptp");
 
@@ -4416,23 +4418,20 @@ ptp_ocp_info(struct ptp_ocp *bp)
 	};
 	struct device *dev = &bp->pdev->dev;
 	u32 reg;
+	int i;
 
 	ptp_ocp_phc_info(bp);
 
-	ptp_ocp_serial_info(dev, "GNSS", bp->gnss_port.line,
-			    bp->gnss_port.baud);
-	ptp_ocp_serial_info(dev, "GNSS2", bp->gnss2_port.line,
-			    bp->gnss2_port.baud);
-	ptp_ocp_serial_info(dev, "MAC", bp->mac_port.line, bp->mac_port.baud);
-	if (bp->nmea_out && bp->nmea_port.line != -1) {
-		bp->nmea_port.baud = -1;
+	for (i = 0; i < __PORT_COUNT; i++) {
+		if (i == PORT_NMEA && bp->nmea_out && bp->port[PORT_NMEA].line != -1) {
+			bp->port[PORT_NMEA].baud = -1;
 
-		reg = ioread32(&bp->nmea_out->uart_baud);
-		if (reg < ARRAY_SIZE(nmea_baud))
-			bp->nmea_port.baud = nmea_baud[reg];
-
-		ptp_ocp_serial_info(dev, "NMEA", bp->nmea_port.line,
-				    bp->nmea_port.baud);
+			reg = ioread32(&bp->nmea_out->uart_baud);
+			if (reg < ARRAY_SIZE(nmea_baud))
+				bp->port[PORT_NMEA].baud = nmea_baud[reg];
+		}
+		ptp_ocp_serial_info(dev, ptp_ocp_tty_port_name(i), bp->port[i].line,
+				    bp->port[i].baud);
 	}
 }
 
@@ -4473,14 +4472,9 @@ ptp_ocp_detach(struct ptp_ocp *bp)
 	for (i = 0; i < 4; i++)
 		if (bp->signal_out[i])
 			ptp_ocp_unregister_ext(bp->signal_out[i]);
-	if (bp->gnss_port.line != -1)
-		serial8250_unregister_port(bp->gnss_port.line);
-	if (bp->gnss2_port.line != -1)
-		serial8250_unregister_port(bp->gnss2_port.line);
-	if (bp->mac_port.line != -1)
-		serial8250_unregister_port(bp->mac_port.line);
-	if (bp->nmea_port.line != -1)
-		serial8250_unregister_port(bp->nmea_port.line);
+	for (i = 0; i < __PORT_COUNT; i++)
+		if (bp->port[i].line != -1)
+			serial8250_unregister_port(bp->port[i].line);
 	platform_device_unregister(bp->spi_flash);
 	platform_device_unregister(bp->i2c_ctrl);
 	if (bp->i2c_clk)
-- 
2.43.5

[PATCH net v7 2/3] ptp: ocp: adjust sysfs entries to expose tty information

[Vadim Fedorenko]

Implement additional attribute group to expose serial port information.
Fixes tag points to the commit which introduced the change in serial
port subsystem and made it impossible to use symlinks.

Fixes: b286f4e87e32 ("serial: core: Move tty and serdev to be children of serial core port device")
Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
---
 drivers/ptp/ptp_ocp.c | 62 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 51 insertions(+), 11 deletions(-)

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index 46369de8e30b..e7479b9b90cb 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -3361,6 +3361,54 @@ static EXT_ATTR_RO(freq, frequency, 1);
 static EXT_ATTR_RO(freq, frequency, 2);
 static EXT_ATTR_RO(freq, frequency, 3);
 
+static ssize_t
+ptp_ocp_tty_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	struct ptp_ocp *bp = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "ttyS%d", bp->port[(uintptr_t)ea->var].line);
+}
+
+static umode_t
+ptp_ocp_timecard_tty_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+	struct ptp_ocp *bp = dev_get_drvdata(kobj_to_dev(kobj));
+	struct ptp_ocp_serial_port *port;
+	struct device_attribute *dattr;
+	struct dev_ext_attribute *ea;
+
+	if (strncmp(attr->name, "tty", 3))
+		return attr->mode;
+
+	dattr = container_of(attr, struct device_attribute, attr);
+	ea = container_of(dattr, struct dev_ext_attribute, attr);
+	port = &bp->port[(uintptr_t)ea->var];
+	return port->line == -1 ? 0 : 0444;
+}
+
+#define EXT_TTY_ATTR_RO(_name, _val)			\
+	struct dev_ext_attribute dev_attr_tty##_name =	\
+		{ __ATTR(tty##_name, 0444, ptp_ocp_tty_show, NULL), (void *)_val }
+
+static EXT_TTY_ATTR_RO(GNSS, PORT_GNSS);
+static EXT_TTY_ATTR_RO(GNSS2, PORT_GNSS2);
+static EXT_TTY_ATTR_RO(MAC, PORT_MAC);
+static EXT_TTY_ATTR_RO(NMEA, PORT_NMEA);
+static struct attribute *ptp_ocp_timecard_tty_attrs[] = {
+	&dev_attr_ttyGNSS.attr.attr,
+	&dev_attr_ttyGNSS2.attr.attr,
+	&dev_attr_ttyMAC.attr.attr,
+	&dev_attr_ttyNMEA.attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ptp_ocp_timecard_tty_group = {
+	.name = "tty",
+	.attrs = ptp_ocp_timecard_tty_attrs,
+	.is_visible = ptp_ocp_timecard_tty_is_visible,
+};
+
 static ssize_t
 serialnum_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
@@ -3790,6 +3838,7 @@ static const struct attribute_group fb_timecard_group = {
 
 static const struct ocp_attr_group fb_timecard_groups[] = {
 	{ .cap = OCP_CAP_BASIC,	    .group = &fb_timecard_group },
+	{ .cap = OCP_CAP_BASIC,	    .group = &ptp_ocp_timecard_tty_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal0_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal1_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal2_group },
@@ -3829,6 +3878,7 @@ static const struct attribute_group art_timecard_group = {
 
 static const struct ocp_attr_group art_timecard_groups[] = {
 	{ .cap = OCP_CAP_BASIC,	    .group = &art_timecard_group },
+	{ .cap = OCP_CAP_BASIC,	    .group = &ptp_ocp_timecard_tty_group },
 	{ },
 };
 
@@ -3856,6 +3906,7 @@ static const struct attribute_group adva_timecard_group = {
 
 static const struct ocp_attr_group adva_timecard_groups[] = {
 	{ .cap = OCP_CAP_BASIC,	    .group = &adva_timecard_group },
+	{ .cap = OCP_CAP_BASIC,	    .group = &ptp_ocp_timecard_tty_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal0_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal1_group },
 	{ .cap = OCP_CAP_FREQ,	    .group = &fb_timecard_freq0_group },
@@ -4361,14 +4412,6 @@ ptp_ocp_complete(struct ptp_ocp *bp)
 {
 	struct pps_device *pps;
 	char buf[32];
-	int i;
-
-	for (i = 0; i < __PORT_COUNT; i++) {
-		if (bp->port[i].line != -1) {
-			sprintf(buf, "ttyS%d", bp->port[i].line);
-			ptp_ocp_link_child(bp, buf, ptp_ocp_tty_port_name(i));
-		}
-	}
 
 	sprintf(buf, "ptp%d", ptp_clock_index(bp->ptp));
 	ptp_ocp_link_child(bp, buf, "ptp");
@@ -4440,9 +4483,6 @@ ptp_ocp_detach_sysfs(struct ptp_ocp *bp)
 {
 	struct device *dev = &bp->dev;
 
-	sysfs_remove_link(&dev->kobj, "ttyGNSS");
-	sysfs_remove_link(&dev->kobj, "ttyGNSS2");
-	sysfs_remove_link(&dev->kobj, "ttyMAC");
 	sysfs_remove_link(&dev->kobj, "ptp");
 	sysfs_remove_link(&dev->kobj, "pps");
 }
-- 
2.43.5

[PATCH net v7 3/3] docs: ABI: update OCP TimeCard sysfs entries

[Vadim Fedorenko]

Update documentation according to the changes in the driver.

New attributes group tty is exposed and ttyGNSS, ttyGNSS2, ttyMAC and
ttyNMEA are moved to this group. Also, these attributes are no more
links to the devices but rather simple text files containing names of
tty devices.

Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
---
 Documentation/ABI/testing/sysfs-timecard | 31 ++++++++++++++----------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-timecard b/Documentation/ABI/testing/sysfs-timecard
index 220478156297..3ae41b7634ac 100644
--- a/Documentation/ABI/testing/sysfs-timecard
+++ b/Documentation/ABI/testing/sysfs-timecard
@@ -258,24 +258,29 @@ Description:	(RW) When retrieving the PHC with the PTP SYS_OFFSET_EXTENDED
 		the estimated point where the FPGA latches the PHC time.  This
 		value may be changed by writing an unsigned integer.
 
-What:		/sys/class/timecard/ocpN/ttyGNSS
-What:		/sys/class/timecard/ocpN/ttyGNSS2
-Date:		September 2021
+What:		/sys/class/timecard/ocpN/tty
+Date:		August 2024
+Contact:	Vadim Fedorenko <vadim.fedorenko@linux.dev>
+Description:	(RO) Directory containing the sysfs nodes for TTY attributes
+
+What:		/sys/class/timecard/ocpN/tty/ttyGNSS
+What:		/sys/class/timecard/ocpN/tty/ttyGNSS2
+Date:		August 2024
 Contact:	Jonathan Lemon <jonathan.lemon@gmail.com>
-Description:	These optional attributes link to the TTY serial ports
-		associated with the GNSS devices.
+Description:	(RO) These optional attributes contain names of the TTY serial
+		ports associated with the GNSS devices.
 
-What:		/sys/class/timecard/ocpN/ttyMAC
-Date:		September 2021
+What:		/sys/class/timecard/ocpN/tty/ttyMAC
+Date:		August 2024
 Contact:	Jonathan Lemon <jonathan.lemon@gmail.com>
-Description:	This optional attribute links to the TTY serial port
-		associated with the Miniature Atomic Clock.
+Description:	(RO) This optional attribute contains name of the TTY serial
+		port associated with the Miniature Atomic Clock.
 
-What:		/sys/class/timecard/ocpN/ttyNMEA
-Date:		September 2021
+What:		/sys/class/timecard/ocpN/tty/ttyNMEA
+Date:		August 2024
 Contact:	Jonathan Lemon <jonathan.lemon@gmail.com>
-Description:	This optional attribute links to the TTY serial port
-		which outputs the PHC time in NMEA ZDA format.
+Description:	(RO) This optional attribute contains name of the TTY serial
+		port which outputs the PHC time in NMEA ZDA format.
 
 What:		/sys/class/timecard/ocpN/utc_tai_offset
 Date:		September 2021
-- 
2.43.5

Re: [PATCH net v7 0/3] ptp: ocp: fix serial port information export

[Greg Kroah-Hartman]

On Thu, Aug 29, 2024 at 11:36:00AM -0700, Vadim Fedorenko wrote:
> Starting v6.8 the serial port subsystem changed the hierarchy of devices
> and symlinks are not working anymore. Previous discussion made it clear
> that the idea of symlinks for tty devices was wrong by design [1].
> This series implements additional attributes to expose the information
> and removes symlinks for tty devices.
> 
> [1] https://lore.kernel.org/netdev/2024060503-subsonic-pupil-bbee@gregkh/
> 
> v6 -> v7:
> - fix issues with applying patches
> v5 -> v6:
> - split conversion to array to separate patch per Jiri's feedback
> - move changelog to cover letter
> v4 -> v5:
> - remove unused variable in ptp_ocp_tty_show
> v3 -> v4:
> - re-organize info printing to use ptp_ocp_tty_port_name()
> - keep uintptr_t to be consistent with other code
> v2 -> v3:
> - replace serial ports definitions with array and enum for index
> - replace pointer math with direct array access
> - nit in documentation spelling
> v1 -> v2:
> - add Documentation/ABI changes
> 
> Vadim Fedorenko (3):
>   ptp: ocp: convert serial ports to array
>   ptp: ocp: adjust sysfs entries to expose tty information
>   docs: ABI: update OCP TimeCard sysfs entries
> 
>  Documentation/ABI/testing/sysfs-timecard |  31 +++--
>  drivers/ptp/ptp_ocp.c                    | 168 ++++++++++++++---------
>  2 files changed, 119 insertions(+), 80 deletions(-)

Thanks for doing this:

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH net v7 2/3] ptp: ocp: adjust sysfs entries to expose tty information

[Paolo Abeni]

On 8/29/24 20:36, Vadim Fedorenko wrote:
> diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
> index 46369de8e30b..e7479b9b90cb 100644
> --- a/drivers/ptp/ptp_ocp.c
> +++ b/drivers/ptp/ptp_ocp.c
> @@ -3361,6 +3361,54 @@ static EXT_ATTR_RO(freq, frequency, 1);
>   static EXT_ATTR_RO(freq, frequency, 2);
>   static EXT_ATTR_RO(freq, frequency, 3);
>   
> +static ssize_t
> +ptp_ocp_tty_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct dev_ext_attribute *ea = to_ext_attr(attr);
> +	struct ptp_ocp *bp = dev_get_drvdata(dev);
> +
> +	return sysfs_emit(buf, "ttyS%d", bp->port[(uintptr_t)ea->var].line);

Out of sheer ignorance on my side, why a trailing '\n' is not needed 
here? do we need to copy the format string from the old link verbatim?

Thanks!

Paolo

Re: [PATCH net v7 2/3] ptp: ocp: adjust sysfs entries to expose tty information

[Vadim Fedorenko]

On 03/09/2024 11:35, Paolo Abeni wrote:
> 
> 
> On 8/29/24 20:36, Vadim Fedorenko wrote:
>> diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
>> index 46369de8e30b..e7479b9b90cb 100644
>> --- a/drivers/ptp/ptp_ocp.c
>> +++ b/drivers/ptp/ptp_ocp.c
>> @@ -3361,6 +3361,54 @@ static EXT_ATTR_RO(freq, frequency, 1);
>>   static EXT_ATTR_RO(freq, frequency, 2);
>>   static EXT_ATTR_RO(freq, frequency, 3);
>> +static ssize_t
>> +ptp_ocp_tty_show(struct device *dev, struct device_attribute *attr, 
>> char *buf)
>> +{
>> +    struct dev_ext_attribute *ea = to_ext_attr(attr);
>> +    struct ptp_ocp *bp = dev_get_drvdata(dev);
>> +
>> +    return sysfs_emit(buf, "ttyS%d", bp->port[(uintptr_t)ea->var].line);
> 
> Out of sheer ignorance on my side, why a trailing '\n' is not needed 
> here? do we need to copy the format string from the old link verbatim?
> 

Hi Paolo!

Yes, I would like to preserve the format used with old symlink option.

Thanks,
Vadim

Re: [PATCH net v7 0/3] ptp: ocp: fix serial port information export

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Thu, 29 Aug 2024 11:36:00 -0700 you wrote:
> Starting v6.8 the serial port subsystem changed the hierarchy of devices
> and symlinks are not working anymore. Previous discussion made it clear
> that the idea of symlinks for tty devices was wrong by design [1].
> This series implements additional attributes to expose the information
> and removes symlinks for tty devices.
> 
> [1] https://lore.kernel.org/netdev/2024060503-subsonic-pupil-bbee@gregkh/
> 
> [...]

Here is the summary with links:
  - [net,v7,1/3] ptp: ocp: convert serial ports to array
    https://git.kernel.org/netdev/net/c/d7875b4b078f
  - [net,v7,2/3] ptp: ocp: adjust sysfs entries to expose tty information
    https://git.kernel.org/netdev/net/c/82ace0c8fe9b
  - [net,v7,3/3] docs: ABI: update OCP TimeCard sysfs entries
    https://git.kernel.org/netdev/net/c/40bec579d4c7

You are awesome, thank you!
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