NAK, this needs to work _with_ the SFP support already merged into the
kernel, rather than as an entirely separate driver.
On Tue, Jun 26, 2018 at 01:34:34PM +0000, Gabriel Matni wrote:
> 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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