From: Gabriel Matni <gabriel.matni@xxxxxxxx>
This driver supports the Small Form Factor Pluggable (SFP) Transceivers
that implement the Digital Diagnostic Monitoring Interface (DDMI) as
defined in SFF-8472. It currently supports temperature monitoring.
Signed-off-by: Gabriel Matni <gabriel.matni@xxxxxxxx>
---
drivers/hwmon/Kconfig | 11 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/sfpmon.c | 299 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 311 insertions(+)
create mode 100644 drivers/hwmon/sfpmon.c
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index f10840ad465c..52de64ccdcfa 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1357,6 +1357,17 @@ config SENSORS_S3C_RAW
Say Y here if you want to include raw copies of all the ADC
channels in sysfs.
+config SENSORS_SFP
+ tristate "Small Form Factor Pluggable (SFP) Transceiver"
+ depends on I2C
+ help
+ If you say yes here you get support for the integrated sensors in
+ SFP/SFP+ modules that implement the Digital Diagnostic Monitoring
+ Interface (DDMI) as defined in SFF-8472.
+
+ This driver can also be built as a module. If so, the module
+ will be called sfpmon.
+
config SENSORS_SIS5595
tristate "Silicon Integrated Systems Corp. SiS5595"
depends on PCI
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index e7d52a36e6c4..d687b6667c1c 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -145,6 +145,7 @@ obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o
obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o
obj-$(CONFIG_SENSORS_SCH5636) += sch5636.o
+obj-$(CONFIG_SENSORS_SFP) += sfpmon.o
obj-$(CONFIG_SENSORS_SHT15) += sht15.o
obj-$(CONFIG_SENSORS_SHT21) += sht21.o
obj-$(CONFIG_SENSORS_SHT3x) += sht3x.o
diff --git a/drivers/hwmon/sfpmon.c b/drivers/hwmon/sfpmon.c
new file mode 100644
index 000000000000..7744577348f1
--- /dev/null
+++ b/drivers/hwmon/sfpmon.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Hardware monitoring driver for SFP/SFP+ modules that implement the
+ * Digital Diagnostic Monitoring Interface (DDMI) as defined in SFF-8472.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/of.h>
+
+#define DRIVER_NAME "sfpmon"
+
+/* id chip registers */
+#define SFF_8472_IDENTIFIER 0
+#define SFF_8472_DIAG_TYPE 92
+
+/* monitoring chip registers */
+#define SFF_8472_TEMP_HIGH_ALARM 0
+#define SFF_8472_TEMP_LOW_ALARM 2
+#define SFF_8472_TEMP_HIGH_WARN 4
+#define SFF_8472_TEMP_LOW_WARN 6
+#define SFF_8472_T_SLOPE 84
+#define SFF_8472_T_OFFSET 86
+#define SFF_8472_TEMP 96
+
+struct calib_info {
+ bool avail;
+ bool external;
+ u16 temp_slope;
+ s16 temp_offset;
+};
+
+struct sfp_data {
+ struct i2c_client *id_client;
+ struct i2c_client *ddmi_client;
+};
+
+static int sfp_detect(struct i2c_client *id, bool *detected)
+{
+ int ret;
+ s32 val;
+
+ val = i2c_smbus_read_byte_data(id, SFF_8472_IDENTIFIER);
+ if (val < 0) {
+ ret = val;
+ *detected = false;
+ goto abort;
+ }
+
+ *detected = (val == 3);
+
+ ret = 0;
+abort:
+ return ret;
+}
+
+static int sfp_get_calib_info(struct i2c_client *id, struct i2c_client *ddmi,
+ struct calib_info *calib)
+{
+ int ret;
+ s32 val;
+
+ val = i2c_smbus_read_byte_data(id, SFF_8472_DIAG_TYPE);
+ if (val < 0) {
+ ret = val;
+ goto abort;
+ }
+
+ calib->avail = !!(val & BIT(6));
+ calib->external = !!(val & BIT(4));
+
+ if (calib->avail && calib->external) {
+ u16 data;
+
+ val = i2c_smbus_read_word_data(ddmi, SFF_8472_T_SLOPE);
+ if (unlikely(val < 0)) {
+ ret = val;
+ goto abort;
+ }
+ data = be16_to_cpu(val & 0xFFFF);
+ calib->temp_slope = *(s16 *)&data;
+
+ val = i2c_smbus_read_word_data(ddmi, SFF_8472_T_OFFSET);
+ if (unlikely(val < 0)) {
+ ret = val;
+ goto abort;
+ }
+ data = be16_to_cpu(val & 0xFFFF);
+ calib->temp_offset = *(s16 *)&data;
+ }
+
+ ret = 0;
+abort:
+ return ret;
+}
+
+static int sfp_get_temp(struct sfp_data *priv, u8 addr, long *temp_mC)
+{
+ int ret;
+ struct calib_info calib = {0};
+ s32 temp, val;
+ u16 data;
+ bool detected;
+
+ ret = sfp_detect(priv->id_client, &detected);
+ if (ret < 0)
+ goto abort;
+
+ if (!detected) {
+ ret = -ENODEV;
+ goto abort;
+ }
+
+ ret = sfp_get_calib_info(priv->id_client, priv->ddmi_client, &calib);
+ if (ret < 0)
+ goto abort;
+
+ if (!calib.avail) {
+ ret = -ENODEV;
+ goto abort;
+ }
+
+ val = i2c_smbus_read_word_data(priv->ddmi_client, addr);
+ if (unlikely(val < 0)) {
+ ret = val;
+ goto abort;
+ }
+
+ data = be16_to_cpu(val & 0xFFFF);
+ temp = *(s16 *)&data;
+
+ /* To get better precision we keep slope in unit of 1/256 and scale
+ * up the offset accordingly. We also convert to mC by multiplying
+ * by 1000. At the very end we divide by 256*256 (using >>16
+ * operation). The first 256 is to rescale down, and the second
+ * 256 is because the calibration result is in unit of 1/256
+ */
+ if (calib.external)
+ *temp_mC = (((s64) calib.temp_slope * temp +
+ (calib.temp_offset << 8)) * 1000) >> 16;
+ else
+ *temp_mC = ((s64)temp*1000) >> 8;
+
+abort:
+ return ret;
+}
+
+static int sfp_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *temp)
+{
+ struct sfp_data *priv = dev_get_drvdata(dev);
+ int err;
+ u8 reg;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ reg = SFF_8472_TEMP;
+ break;
+ case hwmon_temp_crit:
+ reg = SFF_8472_TEMP_HIGH_ALARM;
+ break;
+ case hwmon_temp_lcrit:
+ reg = SFF_8472_TEMP_LOW_ALARM;
+ break;
+ case hwmon_temp_max:
+ reg = SFF_8472_TEMP_HIGH_WARN;
+ break;
+ case hwmon_temp_min:
+ reg = SFF_8472_TEMP_LOW_WARN;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ err = sfp_get_temp(priv, reg, temp);
+ if (err < 0)
+ return err;
+
+ return 0;
+}
+
+static umode_t sfp_is_visible(const void *data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ if (type != hwmon_temp)
+ return 0;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ case hwmon_temp_crit:
+ case hwmon_temp_lcrit:
+ case hwmon_temp_max:
+ case hwmon_temp_min:
+ return S_IRUGO;
+ default:
+ return 0;
+ }
+}
+
+static u32 ddmi_temp_config[] = {
+ HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_CRIT
+ | HWMON_T_LCRIT,
+ 0
+};
+
+static const struct hwmon_channel_info ddmi_temp = {
+ .type = hwmon_temp,
+ .config = ddmi_temp_config,
+};
+
+static const struct hwmon_channel_info *channel_info[] = {
+ &ddmi_temp,
+ NULL
+};
+
+static const struct hwmon_ops sfp_hwmon_ops = {
+ .is_visible = sfp_is_visible,
+ .read = sfp_read,
+};
+
+static const struct hwmon_chip_info sfp_chip_info = {
+ .ops = &sfp_hwmon_ops,
+ .info = channel_info,
+};
+
+static int sfp_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct device *hwmon_dev;
+ struct device_node *id_node;
+ struct sfp_data *priv;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_WORD_DATA)) {
+ dev_err(dev,
+ "adapter doesn't support SMBus word transactions\n");
+ return -ENODEV;
+ }
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, priv);
+
+ priv->ddmi_client = client;
+
+ id_node = of_parse_phandle(client->dev.of_node, "id", 0);
+ if (id_node) {
+ priv->id_client = of_find_i2c_device_by_node(id_node);
+ of_node_put(id_node);
+ }
+
+ if (!priv->id_client) {
+ dev_err(dev, "ID client missing\n");
+ return -ENODEV;
+ }
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+ priv, &sfp_chip_info, NULL);
+
+ if (IS_ERR(hwmon_dev)) {
+ dev_err(dev, "unable to register sfp hwmon device\n");
+ return PTR_ERR(hwmon_dev);
+ }
+
+ return 0;
+}
+
+static const struct i2c_device_id sfp_id[] = {
+ { "sfp", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, sfp_id);
+
+static const struct of_device_id sfp_of_match[] = {
+ { .compatible = "sfp,ddmi" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, sfp_of_match);
+
+static struct i2c_driver sfp_driver = {
+ .driver.name = DRIVER_NAME,
+ .driver.of_match_table = of_match_ptr(sfp_of_match),
+ .probe = sfp_probe,
+ .id_table = sfp_id,
+};
+
+module_i2c_driver(sfp_driver);
+
+MODULE_AUTHOR("Gabriel Matni <gabriel.matni@xxxxxxxx>");
+MODULE_DESCRIPTION("SFP/SFP+ hwmon driver");
+MODULE_LICENSE("GPL");
--
2.7.4
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