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Subject[PATCH v2 2/4] ntb: idt: Add basic hwmon sysfs interface
Date
IDT PCIe switches provide an embedded temperature sensor working
within [0; 127.5]C with resolution of 0.5C. They also can generate
a PCIe upstream interrupt in case if the temperature passes through
specified thresholds. Since this thresholds interface is very broken
the created hwmon-sysfs interface exposes only the next set of hwmon
nodes: current input temperature, lowest and highest values measured,
history resetting, value offset. HWmon alarm interface isn't provided.

IDT PCIe switch also've got an ADC/filter settings of the sensor.
This driver doesn't expose them to the hwmon-sysfs interface at the
moment, except the offset node.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---

Changelog v2:
- Add "select HWMON" to the NTB_IDT kconfig

drivers/ntb/hw/idt/Kconfig | 1 +
drivers/ntb/hw/idt/ntb_hw_idt.c | 182 ++++++++++++++++++++++++++++++++++++++++
drivers/ntb/hw/idt/ntb_hw_idt.h | 24 +++++-
3 files changed, 206 insertions(+), 1 deletion(-)

diff --git a/drivers/ntb/hw/idt/Kconfig b/drivers/ntb/hw/idt/Kconfig
index b360e5613b9f..2ed147368fa8 100644
--- a/drivers/ntb/hw/idt/Kconfig
+++ b/drivers/ntb/hw/idt/Kconfig
@@ -1,6 +1,7 @@
config NTB_IDT
tristate "IDT PCIe-switch Non-Transparent Bridge support"
depends on PCI
+ select HWMON
help
This driver supports NTB of cappable IDT PCIe-switches.

diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index c086ae5c601c..f12088c6a92d 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -49,11 +49,14 @@
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
+#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/aer.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/debugfs.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
#include <linux/ntb.h>

#include "ntb_hw_idt.h"
@@ -1925,6 +1928,153 @@ static void idt_read_temp(struct idt_ntb_dev *ndev,
}

/*
+ * idt_write_temp() - write temperature to the chip sensor register
+ * @ntb: NTB device context.
+ * @type: IN - type of the temperature value to change
+ * @val: IN - integer value of temperature in millidegree Celsius
+ */
+static void idt_write_temp(struct idt_ntb_dev *ndev,
+ const enum idt_temp_val type, const long val)
+{
+ unsigned int reg;
+ u32 data;
+ u8 fmt;
+
+ /* Retrieve the properly formatted temperature value */
+ fmt = idt_temp_get_fmt(val);
+
+ mutex_lock(&ndev->hwmon_mtx);
+ switch (type) {
+ case IDT_TEMP_LOW:
+ reg = IDT_SW_TMPALARM;
+ data = SET_FIELD(TMPALARM_LTEMP, idt_sw_read(ndev, reg), fmt) &
+ ~IDT_TMPALARM_IRQ_MASK;
+ break;
+ case IDT_TEMP_HIGH:
+ reg = IDT_SW_TMPALARM;
+ data = SET_FIELD(TMPALARM_HTEMP, idt_sw_read(ndev, reg), fmt) &
+ ~IDT_TMPALARM_IRQ_MASK;
+ break;
+ case IDT_TEMP_OFFSET:
+ reg = IDT_SW_TMPADJ;
+ data = SET_FIELD(TMPADJ_OFFSET, idt_sw_read(ndev, reg), fmt);
+ break;
+ default:
+ goto inval_spin_unlock;
+ }
+
+ idt_sw_write(ndev, reg, data);
+
+inval_spin_unlock:
+ mutex_unlock(&ndev->hwmon_mtx);
+}
+
+/*
+ * idt_sysfs_show_temp() - printout corresponding temperature value
+ * @dev: Pointer to the NTB device structure
+ * @da: Sensor device attribute structure
+ * @buf: Buffer to print temperature out
+ *
+ * Return: Number of written symbols or negative error
+ */
+static ssize_t idt_sysfs_show_temp(struct device *dev,
+ struct device_attribute *da, char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct idt_ntb_dev *ndev = dev_get_drvdata(dev);
+ enum idt_temp_val type = attr->index;
+ long mdeg;
+
+ idt_read_temp(ndev, type, &mdeg);
+ return sprintf(buf, "%ld\n", mdeg);
+}
+
+/*
+ * idt_sysfs_set_temp() - set corresponding temperature value
+ * @dev: Pointer to the NTB device structure
+ * @da: Sensor device attribute structure
+ * @buf: Buffer to print temperature out
+ * @count: Size of the passed buffer
+ *
+ * Return: Number of written symbols or negative error
+ */
+static ssize_t idt_sysfs_set_temp(struct device *dev,
+ struct device_attribute *da, const char *buf,
+ size_t count)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct idt_ntb_dev *ndev = dev_get_drvdata(dev);
+ enum idt_temp_val type = attr->index;
+ long mdeg;
+ int ret;
+
+ ret = kstrtol(buf, 10, &mdeg);
+ if (ret)
+ return ret;
+
+ /* Clamp the passed value in accordance with the type */
+ if (type == IDT_TEMP_OFFSET)
+ mdeg = clamp_val(mdeg, IDT_TEMP_MIN_OFFSET,
+ IDT_TEMP_MAX_OFFSET);
+ else
+ mdeg = clamp_val(mdeg, IDT_TEMP_MIN_MDEG, IDT_TEMP_MAX_MDEG);
+
+ idt_write_temp(ndev, type, mdeg);
+
+ return count;
+}
+
+/*
+ * idt_sysfs_reset_hist() - reset temperature history
+ * @dev: Pointer to the NTB device structure
+ * @da: Sensor device attribute structure
+ * @buf: Buffer to print temperature out
+ * @count: Size of the passed buffer
+ *
+ * Return: Number of written symbols or negative error
+ */
+static ssize_t idt_sysfs_reset_hist(struct device *dev,
+ struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ struct idt_ntb_dev *ndev = dev_get_drvdata(dev);
+
+ /* Just set the maximal value to the lowest temperature field and
+ * minimal value to the highest temperature field
+ */
+ idt_write_temp(ndev, IDT_TEMP_LOW, IDT_TEMP_MAX_MDEG);
+ idt_write_temp(ndev, IDT_TEMP_HIGH, IDT_TEMP_MIN_MDEG);
+
+ return count;
+}
+
+/*
+ * Hwmon IDT sysfs attributes
+ */
+static SENSOR_DEVICE_ATTR(temp1_input, 0444, idt_sysfs_show_temp, NULL,
+ IDT_TEMP_CUR);
+static SENSOR_DEVICE_ATTR(temp1_lowest, 0444, idt_sysfs_show_temp, NULL,
+ IDT_TEMP_LOW);
+static SENSOR_DEVICE_ATTR(temp1_highest, 0444, idt_sysfs_show_temp, NULL,
+ IDT_TEMP_HIGH);
+static SENSOR_DEVICE_ATTR(temp1_offset, 0644, idt_sysfs_show_temp,
+ idt_sysfs_set_temp, IDT_TEMP_OFFSET);
+static DEVICE_ATTR(temp1_reset_history, 0200, NULL, idt_sysfs_reset_hist);
+
+/*
+ * Hwmon IDT sysfs attributes group
+ */
+static struct attribute *idt_temp_attrs[] = {
+ &sensor_dev_attr_temp1_input.dev_attr.attr,
+ &sensor_dev_attr_temp1_lowest.dev_attr.attr,
+ &sensor_dev_attr_temp1_highest.dev_attr.attr,
+ &sensor_dev_attr_temp1_offset.dev_attr.attr,
+ &dev_attr_temp1_reset_history.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(idt_temp);
+
+/*
* idt_temp_isr() - temperature sensor alarm events ISR
* @ndev: IDT NTB hardware driver descriptor
* @ntint_sts: NT-function interrupt status
@@ -1956,6 +2106,35 @@ static void idt_temp_isr(struct idt_ntb_dev *ndev, u32 ntint_sts)
idt_get_deg(mdeg), idt_get_deg_frac(mdeg));
}

+/*
+ * idt_init_temp() - initialize temperature sensor interface
+ * @ndev: IDT NTB hardware driver descriptor
+ *
+ * Simple sensor initializarion method is responsible for device switching
+ * on and resource management based hwmon interface registration. Note, that
+ * since the device is shared we won't disable it on remove, but leave it
+ * working until the system is powered off.
+ */
+static void idt_init_temp(struct idt_ntb_dev *ndev)
+{
+ struct device *hwmon;
+
+ /* Enable sensor if it hasn't been already */
+ idt_sw_write(ndev, IDT_SW_TMPCTL, 0x0);
+
+ /* Initialize hwmon interface fields */
+ mutex_init(&ndev->hwmon_mtx);
+
+ hwmon = devm_hwmon_device_register_with_groups(&ndev->ntb.pdev->dev,
+ ndev->swcfg->name, ndev, idt_temp_groups);
+ if (IS_ERR(hwmon)) {
+ dev_err(&ndev->ntb.pdev->dev, "Couldn't create hwmon device");
+ return;
+ }
+
+ dev_dbg(&ndev->ntb.pdev->dev, "Temperature HWmon interface registered");
+}
+
/*=============================================================================
* 8. ISRs related operations
*
@@ -2650,6 +2829,9 @@ static int idt_pci_probe(struct pci_dev *pdev,
/* Initialize Messaging subsystem */
idt_init_msg(ndev);

+ /* Initialize hwmon interface */
+ idt_init_temp(ndev);
+
/* Initialize IDT interrupts handler */
ret = idt_init_isr(ndev);
if (ret != 0)
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.h b/drivers/ntb/hw/idt/ntb_hw_idt.h
index 9dfd6b11a621..032f81cb4d44 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.h
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.h
@@ -47,9 +47,9 @@
#include <linux/pci_ids.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
+#include <linux/mutex.h>
#include <linux/ntb.h>

-
/*
* Macro is used to create the struct pci_device_id that matches
* the supported IDT PCIe-switches
@@ -907,6 +907,10 @@
* TMPSTS register fields related constants
* @IDT_TMPSTS_TEMP_MASK: Current temperature field mask
* @IDT_TMPSTS_TEMP_FLD: Current temperature field offset
+ * @IDT_TMPSTS_LTEMP_MASK: Lowest temperature field mask
+ * @IDT_TMPSTS_LTEMP_FLD: Lowest temperature field offset
+ * @IDT_TMPSTS_HTEMP_MASK: Highest temperature field mask
+ * @IDT_TMPSTS_HTEMP_FLD: Highest temperature field offset
*/
#define IDT_TMPSTS_TEMP_MASK 0x000000FFU
#define IDT_TMPSTS_TEMP_FLD 0
@@ -916,6 +920,20 @@
#define IDT_TMPSTS_HTEMP_FLD 16

/*
+ * TMPALARM register fields related constants
+ * @IDT_TMPALARM_LTEMP_MASK: Lowest temperature field mask
+ * @IDT_TMPALARM_LTEMP_FLD: Lowest temperature field offset
+ * @IDT_TMPALARM_HTEMP_MASK: Highest temperature field mask
+ * @IDT_TMPALARM_HTEMP_FLD: Highest temperature field offset
+ * @IDT_TMPALARM_IRQ_MASK: Alarm IRQ status mask
+ */
+#define IDT_TMPALARM_LTEMP_MASK 0x0000FF00U
+#define IDT_TMPALARM_LTEMP_FLD 8
+#define IDT_TMPALARM_HTEMP_MASK 0x00FF0000U
+#define IDT_TMPALARM_HTEMP_FLD 16
+#define IDT_TMPALARM_IRQ_MASK 0x3F000000U
+
+/*
* TMPADJ register fields related constants
* @IDT_TMPADJ_OFFSET_MASK: Temperature value offset field mask
* @IDT_TMPADJ_OFFSET_FLD: Temperature value offset field offset
@@ -1100,6 +1118,8 @@ struct idt_ntb_peer {
* @msg_mask_lock: Message mask register lock
* @gasa_lock: GASA registers access lock
*
+ * @hwmon_mtx: Temperature sensor interface update mutex
+ *
* @dbgfs_info: DebugFS info node
*/
struct idt_ntb_dev {
@@ -1127,6 +1147,8 @@ struct idt_ntb_dev {
spinlock_t msg_mask_lock;
spinlock_t gasa_lock;

+ struct mutex hwmon_mtx;
+
struct dentry *dbgfs_info;
};
#define to_ndev_ntb(__ntb) container_of(__ntb, struct idt_ntb_dev, ntb)
--
2.12.0
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