ptp: expose the programmable pins via sysfs

This patch adds the sysfs hooks needed in order to get and set the
programmable pin settings.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 118 insertions, 0 deletions

diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index b114a84c63c7..9c5d41421b65 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -51,6 +51,9 @@ struct ptp_clock {
         struct mutex pincfg_mux; /* protect concurrent info->pin_config access */
         wait_queue_head_t tsev_wq;
         int defunct; /* tells readers to go away when clock is being removed */
+        struct device_attribute *pin_dev_attr;
+        struct attribute **pin_attr;
+        struct attribute_group pin_attr_group;
 };
 
 /*
diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c
index 13ec5311746a..302e626fe6b0 100644
--- a/drivers/ptp/ptp_sysfs.c
+++ b/drivers/ptp/ptp_sysfs.c
@@ -18,6 +18,7 @@
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 #include <linux/capability.h>
+#include <linux/slab.h>
 
 #include "ptp_private.h"
 
@@ -42,6 +43,7 @@ PTP_SHOW_INT(max_adjustment, max_adj);
 PTP_SHOW_INT(n_alarms, n_alarm);
 PTP_SHOW_INT(n_external_timestamps, n_ext_ts);
 PTP_SHOW_INT(n_periodic_outputs, n_per_out);
+PTP_SHOW_INT(n_programmable_pins, n_pins);
 PTP_SHOW_INT(pps_available, pps);
 
 static struct attribute *ptp_attrs[] = {
@@ -50,6 +52,7 @@ static struct attribute *ptp_attrs[] = {
         &dev_attr_n_alarms.attr,
         &dev_attr_n_external_timestamps.attr,
         &dev_attr_n_periodic_outputs.attr,
+        &dev_attr_n_programmable_pins.attr,
         &dev_attr_pps_available.attr,
         NULL,
 };
@@ -175,6 +178,63 @@ out:
         return err;
 }
 
+static int ptp_pin_name2index(struct ptp_clock *ptp, const char *name)
+{
+        int i;
+        for (i = 0; i < ptp->info->n_pins; i++) {
+                if (!strcmp(ptp->info->pin_config[i].name, name))
+                        return i;
+        }
+        return -1;
+}
+
+static ssize_t ptp_pin_show(struct device *dev, struct device_attribute *attr,
+                            char *page)
+{
+        struct ptp_clock *ptp = dev_get_drvdata(dev);
+        unsigned int func, chan;
+        int index;
+
+        index = ptp_pin_name2index(ptp, attr->attr.name);
+        if (index < 0)
+                return -EINVAL;
+
+        if (mutex_lock_interruptible(&ptp->pincfg_mux))
+                return -ERESTARTSYS;
+
+        func = ptp->info->pin_config[index].func;
+        chan = ptp->info->pin_config[index].chan;
+
+        mutex_unlock(&ptp->pincfg_mux);
+
+        return snprintf(page, PAGE_SIZE, "%u %u\n", func, chan);
+}
+
+static ssize_t ptp_pin_store(struct device *dev, struct device_attribute *attr,
+                             const char *buf, size_t count)
+{
+        struct ptp_clock *ptp = dev_get_drvdata(dev);
+        unsigned int func, chan;
+        int cnt, err, index;
+
+        cnt = sscanf(buf, "%u %u", &func, &chan);
+        if (cnt != 2)
+                return -EINVAL;
+
+        index = ptp_pin_name2index(ptp, attr->attr.name);
+        if (index < 0)
+                return -EINVAL;
+
+        if (mutex_lock_interruptible(&ptp->pincfg_mux))
+                return -ERESTARTSYS;
+        err = ptp_set_pinfunc(ptp, index, func, chan);
+        mutex_unlock(&ptp->pincfg_mux);
+        if (err)
+                return err;
+
+        return count;
+}
+
 static DEVICE_ATTR(extts_enable, 0220, NULL, extts_enable_store);
 static DEVICE_ATTR(fifo,         0444, extts_fifo_show, NULL);
 static DEVICE_ATTR(period,       0220, NULL, period_store);
@@ -195,9 +255,56 @@ int ptp_cleanup_sysfs(struct ptp_clock *ptp)
         if (info->pps)
                 device_remove_file(dev, &dev_attr_pps_enable);
 
+        if (info->n_pins) {
+                sysfs_remove_group(&dev->kobj, &ptp->pin_attr_group);
+                kfree(ptp->pin_attr);
+                kfree(ptp->pin_dev_attr);
+        }
         return 0;
 }
 
+static int ptp_populate_pins(struct ptp_clock *ptp)
+{
+        struct device *dev = ptp->dev;
+        struct ptp_clock_info *info = ptp->info;
+        int err = -ENOMEM, i, n_pins = info->n_pins;
+
+        ptp->pin_dev_attr = kzalloc(n_pins * sizeof(*ptp->pin_dev_attr),
+                                    GFP_KERNEL);
+        if (!ptp->pin_dev_attr)
+                goto no_dev_attr;
+
+        ptp->pin_attr = kzalloc((1 + n_pins) * sizeof(struct attribute *),
+                                GFP_KERNEL);
+        if (!ptp->pin_attr)
+                goto no_pin_attr;
+
+        for (i = 0; i < n_pins; i++) {
+                struct device_attribute *da = &ptp->pin_dev_attr[i];
+                sysfs_attr_init(&da->attr);
+                da->attr.name = info->pin_config[i].name;
+                da->attr.mode = 0644;
+                da->show = ptp_pin_show;
+                da->store = ptp_pin_store;
+                ptp->pin_attr[i] = &da->attr;
+        }
+
+        ptp->pin_attr_group.name = "pins";
+        ptp->pin_attr_group.attrs = ptp->pin_attr;
+
+        err = sysfs_create_group(&dev->kobj, &ptp->pin_attr_group);
+        if (err)
+                goto no_group;
+        return 0;
+
+no_group:
+        kfree(ptp->pin_attr);
+no_pin_attr:
+        kfree(ptp->pin_dev_attr);
+no_dev_attr:
+        return err;
+}
+
 int ptp_populate_sysfs(struct ptp_clock *ptp)
 {
         struct device *dev = ptp->dev;
@@ -222,7 +329,15 @@ int ptp_populate_sysfs(struct ptp_clock *ptp)
                 if (err)
                         goto out4;
         }
+        if (info->n_pins) {
+                err = ptp_populate_pins(ptp);
+                if (err)
+                        goto out5;
+        }
         return 0;
+out5:
+        if (info->pps)
+                device_remove_file(dev, &dev_attr_pps_enable);
 out4:
         if (info->n_per_out)
                 device_remove_file(dev, &dev_attr_period);