[PATCH v2 06/15] net: dsa: Add support for reporting switch chip temperatures

From: Guenter Roeck
Date: Sun Oct 26 2014 - 12:56:38 EST


Some switches provide chip temperature data.
Add support for reporting it through the hwmon subsystem.

Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
v2:
- Updated headline to reflect what is reported, not how.
- Make added functionality optional with new Kconfig flag
- Register with hwmon subsystem as virtual device (no parent)
- Generate hwmon 'name' attribute from sanitized master network device
name plus _dsaX, where X is the DSA switch index and 'sanitized'
means to pick all characters and digits from the network device name
- Do not use devm_ function to register hwmon device, since the hwmon
device is not associated with a device and thus can not be auto-removed.

include/net/dsa.h | 16 +++++++
net/dsa/Kconfig | 11 +++++
net/dsa/dsa.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 158 insertions(+)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index b765592..55e75e7 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -139,6 +139,14 @@ struct dsa_switch {
*/
struct device *master_dev;

+#ifdef CONFIG_NET_DSA_HWMON
+ /*
+ * Hardware monitoring information
+ */
+ char hwmon_name[IFNAMSIZ + 8];
+ struct device *hwmon_dev;
+#endif
+
/*
* Slave mii_bus and devices for the individual ports.
*/
@@ -242,6 +250,14 @@ struct dsa_switch_driver {
struct ethtool_eee *e);
int (*get_eee)(struct dsa_switch *ds, int port,
struct ethtool_eee *e);
+
+#ifdef CONFIG_NET_DSA_HWMON
+ /* Hardware monitoring */
+ int (*get_temp)(struct dsa_switch *ds, int *temp);
+ int (*get_temp_limit)(struct dsa_switch *ds, int *temp);
+ int (*set_temp_limit)(struct dsa_switch *ds, int temp);
+ int (*get_temp_alarm)(struct dsa_switch *ds, bool *alarm);
+#endif
};

void register_switch_driver(struct dsa_switch_driver *type);
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index a585fd6..5f8ac40 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -11,6 +11,17 @@ config NET_DSA

if NET_DSA

+config NET_DSA_HWMON
+ bool "Distributed Switch Architecture HWMON support"
+ default y
+ depends on HWMON && !(NET_DSA=y && HWMON=m)
+ ---help---
+ Say Y if you want to expose thermal sensor data on switches supported
+ by the Distributed Switch Architecture.
+
+ Some of those switches contain thermal sensors. This data is available
+ via the hwmon sysfs interface and exposes the onboard sensors.
+
# tagging formats
config NET_DSA_TAG_BRCM
bool
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 22f34cf..5edbbca 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -9,6 +9,9 @@
* (at your option) any later version.
*/

+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/hwmon.h>
#include <linux/list.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
@@ -17,6 +20,7 @@
#include <linux/of.h>
#include <linux/of_mdio.h>
#include <linux/of_platform.h>
+#include <linux/sysfs.h>
#include "dsa_priv.h"

char dsa_driver_version[] = "0.1";
@@ -71,6 +75,104 @@ dsa_switch_probe(struct device *host_dev, int sw_addr, char **_name)
return ret;
}

+/* hwmon support ************************************************************/
+
+#ifdef CONFIG_NET_DSA_HWMON
+
+static ssize_t temp1_input_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dsa_switch *ds = dev_get_drvdata(dev);
+ int temp, ret;
+
+ ret = ds->drv->get_temp(ds, &temp);
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", temp * 1000);
+}
+static DEVICE_ATTR_RO(temp1_input);
+
+static ssize_t temp1_max_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dsa_switch *ds = dev_get_drvdata(dev);
+ int temp, ret;
+
+ ret = ds->drv->get_temp_limit(ds, &temp);
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", temp * 1000);
+}
+
+static ssize_t temp1_max_store(struct device *dev,
+ struct device_attribute *attr, const char *buf,
+ size_t count)
+{
+ struct dsa_switch *ds = dev_get_drvdata(dev);
+ int temp, ret;
+
+ ret = kstrtoint(buf, 0, &temp);
+ if (ret < 0)
+ return ret;
+
+ ret = ds->drv->set_temp_limit(ds, DIV_ROUND_CLOSEST(temp, 1000));
+ if (ret < 0)
+ return ret;
+
+ return count;
+}
+static DEVICE_ATTR(temp1_max, S_IRUGO, temp1_max_show, temp1_max_store);
+
+static ssize_t temp1_max_alarm_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dsa_switch *ds = dev_get_drvdata(dev);
+ bool alarm;
+ int ret;
+
+ ret = ds->drv->get_temp_alarm(ds, &alarm);
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", alarm);
+}
+static DEVICE_ATTR_RO(temp1_max_alarm);
+
+static struct attribute *dsa_hwmon_attrs[] = {
+ &dev_attr_temp1_input.attr, /* 0 */
+ &dev_attr_temp1_max.attr, /* 1 */
+ &dev_attr_temp1_max_alarm.attr, /* 2 */
+ NULL
+};
+
+static umode_t dsa_hwmon_attrs_visible(struct kobject *kobj,
+ struct attribute *attr, int index)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct dsa_switch *ds = dev_get_drvdata(dev);
+ struct dsa_switch_driver *drv = ds->drv;
+ umode_t mode = attr->mode;
+
+ if (index == 1) {
+ if (!drv->get_temp_limit)
+ mode = 0;
+ else if (drv->set_temp_limit)
+ mode |= S_IWUSR;
+ } else if (index == 2 && !drv->get_temp_alarm) {
+ mode = 0;
+ }
+ return mode;
+}
+
+static const struct attribute_group dsa_hwmon_group = {
+ .attrs = dsa_hwmon_attrs,
+ .is_visible = dsa_hwmon_attrs_visible,
+};
+__ATTRIBUTE_GROUPS(dsa_hwmon);
+
+#endif /* CONFIG_NET_DSA_HWMON */

/* basic switch operations **************************************************/
static struct dsa_switch *
@@ -225,6 +327,31 @@ dsa_switch_setup(struct dsa_switch_tree *dst, int index,
ds->ports[i] = slave_dev;
}

+#ifdef CONFIG_NET_DSA_HWMON
+ /* If the switch provides a temperature sensor,
+ * register with hardware monitoring subsystem.
+ * Treat registration error as non-fatal and ignore it.
+ */
+ if (drv->get_temp) {
+ const char *netname = netdev_name(dst->master_netdev);
+ char hname[IFNAMSIZ + 1];
+ int i, j;
+
+ /* Create valid hwmon 'name' attribute */
+ for (i = j = 0; i < IFNAMSIZ && netname[i]; i++) {
+ if (isalnum(netname[i]))
+ hname[j++] = netname[i];
+ }
+ hname[j] = '\0';
+ scnprintf(ds->hwmon_name, sizeof(ds->hwmon_name), "%s_dsa%d",
+ hname, index);
+ ds->hwmon_dev = hwmon_device_register_with_groups(NULL,
+ ds->hwmon_name, ds, dsa_hwmon_groups);
+ if (IS_ERR(ds->hwmon_dev))
+ ds->hwmon_dev = NULL;
+ }
+#endif /* CONFIG_NET_DSA_HWMON */
+
return ds;

out_free:
@@ -236,6 +363,10 @@ out:

static void dsa_switch_destroy(struct dsa_switch *ds)
{
+#ifdef CONFIG_NET_DSA_HWMON
+ if (ds->hwmon_dev)
+ hwmon_device_unregister(ds->hwmon_dev);
+#endif
}

#ifdef CONFIG_PM_SLEEP
--
1.9.1

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