[PATCH net] ptp: ocp: adjust sysfs entries to expose tty information

[PATCH net] ptp: ocp: adjust sysfs entries to expose tty information

[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. Implement
additional attributes to expose the information. Fixes tag points to the
commit which introduced the change.

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 | 68 +++++++++++++++++++++++++++++++++----------
 1 file changed, 52 insertions(+), 16 deletions(-)

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index ee2ced88ab34..7a5026656452 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -3346,6 +3346,55 @@ 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);
+	struct ptp_ocp_serial_port *port;
+
+	port = (void *)((uintptr_t)bp + (uintptr_t)ea->var);
+	return sysfs_emit(buf, "ttyS%d", port->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 = (void *)((uintptr_t)bp + (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, offsetof(struct ptp_ocp, gnss_port));
+static EXT_TTY_ATTR_RO(GNSS2, offsetof(struct ptp_ocp, gnss2_port));
+static EXT_TTY_ATTR_RO(MAC, offsetof(struct ptp_ocp, mac_port));
+static EXT_TTY_ATTR_RO(NMEA, offsetof(struct ptp_ocp, nmea_port));
+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)
 {
@@ -3775,6 +3824,7 @@ 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 },
@@ -3814,6 +3864,7 @@ 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 },
 	{ },
 };
 
@@ -3841,6 +3892,7 @@ 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 },
@@ -4352,22 +4404,6 @@ ptp_ocp_complete(struct ptp_ocp *bp)
 	struct pps_device *pps;
 	char buf[32];
 
-	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");
-	}
 	sprintf(buf, "ptp%d", ptp_clock_index(bp->ptp));
 	ptp_ocp_link_child(bp, buf, "ptp");
 
-- 
2.43.5

Re: [PATCH net] ptp: ocp: adjust sysfs entries to expose tty information

[Greg Kroah-Hartman]

On Fri, Aug 02, 2024 at 08:46:34AM -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. Implement
> additional attributes to expose the information. Fixes tag points to the
> commit which introduced the change.
> 
> 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 | 68 +++++++++++++++++++++++++++++++++----------
>  1 file changed, 52 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
> index ee2ced88ab34..7a5026656452 100644
> --- a/drivers/ptp/ptp_ocp.c
> +++ b/drivers/ptp/ptp_ocp.c
> @@ -3346,6 +3346,55 @@ 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);
> +	struct ptp_ocp_serial_port *port;
> +
> +	port = (void *)((uintptr_t)bp + (uintptr_t)ea->var);
> +	return sysfs_emit(buf, "ttyS%d", port->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 = (void *)((uintptr_t)bp + (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, offsetof(struct ptp_ocp, gnss_port));
> +static EXT_TTY_ATTR_RO(GNSS2, offsetof(struct ptp_ocp, gnss2_port));
> +static EXT_TTY_ATTR_RO(MAC, offsetof(struct ptp_ocp, mac_port));
> +static EXT_TTY_ATTR_RO(NMEA, offsetof(struct ptp_ocp, nmea_port));
> +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)
>  {
> @@ -3775,6 +3824,7 @@ 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 },
> @@ -3814,6 +3864,7 @@ 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 },
>  	{ },
>  };
>  
> @@ -3841,6 +3892,7 @@ 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 },
> @@ -4352,22 +4404,6 @@ ptp_ocp_complete(struct ptp_ocp *bp)
>  	struct pps_device *pps;
>  	char buf[32];
>  
> -	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");
> -	}
>  	sprintf(buf, "ptp%d", ptp_clock_index(bp->ptp));
>  	ptp_ocp_link_child(bp, buf, "ptp");
>  
> -- 
> 2.43.5
> 

Hi,

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a patch that has triggered this response.  He used to manually respond
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Re: [PATCH net] ptp: ocp: adjust sysfs entries to expose tty information

[Greg Kroah-Hartman]

On Fri, Aug 02, 2024 at 08:46:34AM -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. Implement
> additional attributes to expose the information. Fixes tag points to the
> commit which introduced the change.

No Documentation/ABI/ updates?

Re: [PATCH net] ptp: ocp: adjust sysfs entries to expose tty information

[Vadim Fedorenko]

On 03.08.2024 08:12, Greg Kroah-Hartman wrote:
> On Fri, Aug 02, 2024 at 08:46:34AM -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. Implement
>> additional attributes to expose the information. Fixes tag points to the
>> commit which introduced the change.
> 
> No Documentation/ABI/ updates?
> 

Ah... totally forgot about it. Will make it in v2,
Thanks!