[PATCH v2 1/6] hwmon: (gxp-fan-ctrl) Add GXP fan controller

From: nick . hawkins
Date: Mon Nov 28 2022 - 18:04:46 EST

From: Nick Hawkins <nick.hawkins@xxxxxxx>

The GXP SoC can support up to 16 fans through the interface provided by
the CPLD. The current support is limited to 8 fans. The fans speeds are
controlled via 8 different PWMs which can vary in value from 0-255. The
fans are also capable of reporting if they have failed to the CPLD which
in turn reports the status to the GXP SoC.

Signed-off-by: Nick Hawkins <nick.hawkins@xxxxxxx>

---

v2:
*Changed number of supported fans from 16 to 8 in code
*Remove last sentence of commit description
*Removed support for fan[0-15]_input in code and documentation
*Changed documentation to limit fan count to 7
*Changed documentation license
*Removed PWM defines
*Added gxp-fan-ctrl to hwmon's index.rst
*Removed mutex
*Added fan_enable support to report if the fan is enabled
*Changed presents to present
*Removed unnecessary ()
*Add comment for plreg reads and calculations
*Add comment for the use of platform power state in code
*Removed use of variable offsets and went with hardcoding instead
*Rewrote driver to use devm_hwmon_device_register_with_info()
*Remove unused header files
*Fix GPL header
*Changed module description
*Add kfree in case of failure to get regmaps or resource
---
Documentation/hwmon/gxp-fan-ctrl.rst | 28 +++
Documentation/hwmon/index.rst | 1 +
drivers/hwmon/Kconfig | 9 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/gxp-fan-ctrl.c | 305 +++++++++++++++++++++++++++
5 files changed, 344 insertions(+)
create mode 100644 Documentation/hwmon/gxp-fan-ctrl.rst
create mode 100644 drivers/hwmon/gxp-fan-ctrl.c

diff --git a/Documentation/hwmon/gxp-fan-ctrl.rst b/Documentation/hwmon/gxp-fan-ctrl.rst
new file mode 100644
index 000000000000..ae3397e81c04
--- /dev/null
+++ b/Documentation/hwmon/gxp-fan-ctrl.rst
@@ -0,0 +1,28 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Kernel driver gxp-fan-ctrl
+==========================
+
+Supported chips:
+
+ * HPE GXP SOC
+
+Author: Nick Hawkins <nick.hawkins@xxxxxxx>
+
+
+Description
+-----------
+
+gxp-fan-ctrl is a driver which provides fan control for the hpe gxp soc.
+The driver allows the gathering of fan status and the use of fan
+PWM control.
+
+
+Sysfs attributes
+----------------
+
+======================= ===========================================================
+pwm[0-7] Fan 0 to 7 respective PWM value (0-255)
+fan[0-7]_fault Fan 0 to 7 respective fault status: 1 fail, 0 ok
+fan[0-7]_enable Fan 0 to 7 respective enabled status: 1 enabled, 0 disabled
+======================= ===========================================================
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index f7113b0f8b2a..b319ab173d1d 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -73,6 +73,7 @@ Hardware Monitoring Kernel Drivers
g762
gsc-hwmon
gl518sm
+ gxp-fan-ctrl
hih6130
ibmaem
ibm-cffps
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index e70d9614bec2..9e0427f20141 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -705,6 +705,15 @@ config SENSORS_GPIO_FAN
This driver can also be built as a module. If so, the module
will be called gpio-fan.

+config SENSORS_GXP_FAN_CTRL
+ tristate "HPE GXP fan controller"
+ depends on ARCH_HPE_GXP || COMPILE_TEST
+ help
+ If you say yes here you get support for GXP fan control functionality.
+
+ The GXP controls fan function via the CPLD through the use of PWM
+ registers. This driver reports status and pwm setting of the fans.
+
config SENSORS_HIH6130
tristate "Honeywell Humidicon HIH-6130 humidity/temperature sensor"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 007e829d1d0d..b474dcc708c4 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -83,6 +83,7 @@ obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o
obj-$(CONFIG_SENSORS_GL520SM) += gl520sm.o
obj-$(CONFIG_SENSORS_GSC) += gsc-hwmon.o
obj-$(CONFIG_SENSORS_GPIO_FAN) += gpio-fan.o
+obj-$(CONFIG_SENSORS_GXP_FAN_CTRL) += gxp-fan-ctrl.o
obj-$(CONFIG_SENSORS_HIH6130) += hih6130.o
obj-$(CONFIG_SENSORS_ULTRA45) += ultra45_env.o
obj-$(CONFIG_SENSORS_I5500) += i5500_temp.o
diff --git a/drivers/hwmon/gxp-fan-ctrl.c b/drivers/hwmon/gxp-fan-ctrl.c
new file mode 100644
index 000000000000..0b03d33a3a7b
--- /dev/null
+++ b/drivers/hwmon/gxp-fan-ctrl.c
@@ -0,0 +1,305 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define OFS_FAN_INST 0 /* Is 0 because plreg base will be set at INST */
+#define OFS_FAN_FAIL 2 /* Is 2 bytes after base */
+#define OFS_SEVSTAT 0 /* Is 0 because fn2 base will be set at SEVSTAT */
+#define POWER_BIT 24
+
+struct gxp_fan_ctrl_drvdata {
+ struct device *dev;
+ struct device *hwmon_dev;
+ struct regmap *plreg_map; /* Programmable logic register regmap */
+ struct regmap *fn2_map; /* Function 2 regmap */
+ void __iomem *base;
+};
+
+static bool fan_installed(struct device *dev, int fan)
+{
+ struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
+ u32 val;
+
+ regmap_read(drvdata->plreg_map, OFS_FAN_INST, &val);
+ if (val & BIT(fan))
+ return 1;
+ else
+ return 0;
+}
+
+static long fan_failed(struct device *dev, int fan)
+{
+ struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
+ u32 val;
+
+ /*
+ * The offset for fan fail is 2 which is not word aligned.
+ * Read from fan installed which is 0 and shift value.
+ */
+
+ regmap_read(drvdata->plreg_map, OFS_FAN_INST, &val);
+
+ if ((val >> (8 * OFS_FAN_FAIL)) & BIT(fan))
+ return 1;
+ else
+ return 0;
+}
+
+static long fan_enabled(struct device *dev, int fan)
+{
+ struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
+ unsigned int reg;
+
+ /*
+ * Check the power status as if the platform is off the value
+ * reported for the PWM will be incorrect. Report fan as
+ * disabled.
+ */
+ regmap_read(drvdata->fn2_map, OFS_SEVSTAT, &reg);
+
+ /* If Fan is installed and the system is on it is enabled */
+ if ((reg & BIT(POWER_BIT)) && fan_installed(dev, fan))
+ return 1;
+
+ /* Platform power is off, fan is disabled */
+ return 0;
+}
+
+static int gxp_pwm_write(struct device *dev, u32 attr, int channel, long val)
+{
+ struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
+
+ switch (attr) {
+ case hwmon_pwm_input:
+ if (val > 255)
+ return -EINVAL;
+ writeb(val, drvdata->base + channel);
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int gxp_fan_ctrl_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long val)
+{
+ switch (type) {
+ case hwmon_pwm:
+ return gxp_pwm_write(dev, attr, channel, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int gxp_fan_read(struct device *dev, u32 attr, int channel, long *val)
+{
+ switch (attr) {
+ case hwmon_fan_enable:
+ *val = fan_enabled(dev, channel);
+ return 0;
+ case hwmon_fan_fault:
+ *val = fan_failed(dev, channel);
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int gxp_pwm_read(struct device *dev, u32 attr, int channel, long *val)
+{
+ struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
+ unsigned int reg;
+
+ /*
+ * Check the power status of the platform. If the platform is off
+ * the value reported for the PWM will be incorrect. In this case
+ * report a PWM of zero.
+ */
+ regmap_read(drvdata->fn2_map, 0, &reg);
+ if (reg & BIT(POWER_BIT)) {
+ /* If Fan present, then read it. */
+ *val = fan_installed(dev, channel) ? readb(drvdata->base + channel) : 0;
+ } else {
+ *val = 0;
+ }
+
+ return 0;
+}
+
+static int gxp_fan_ctrl_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ switch (type) {
+ case hwmon_fan:
+ return gxp_fan_read(dev, attr, channel, val);
+ case hwmon_pwm:
+ return gxp_pwm_read(dev, attr, channel, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static umode_t gxp_fan_ctrl_is_visible(const void *_data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ umode_t mode = 0;
+
+ switch (type) {
+ case hwmon_fan:
+ switch (attr) {
+ case hwmon_fan_enable:
+ case hwmon_fan_fault:
+ mode = 0444;
+ default:
+ break;
+ }
+ case hwmon_pwm:
+ switch (attr) {
+ case hwmon_pwm_input:
+ mode = 0644;
+ default:
+ break;
+ }
+ default:
+ break;
+ }
+
+ return mode;
+}
+
+static const struct hwmon_ops gxp_fan_ctrl_ops = {
+ .is_visible = gxp_fan_ctrl_is_visible,
+ .read = gxp_fan_ctrl_read,
+ .write = gxp_fan_ctrl_write,
+};
+
+static const struct hwmon_channel_info *gxp_fan_ctrl_info[] = {
+ HWMON_CHANNEL_INFO(fan,
+ HWMON_F_FAULT | HWMON_F_ENABLE,
+ HWMON_F_FAULT | HWMON_F_ENABLE,
+ HWMON_F_FAULT | HWMON_F_ENABLE,
+ HWMON_F_FAULT | HWMON_F_ENABLE,
+ HWMON_F_FAULT | HWMON_F_ENABLE,
+ HWMON_F_FAULT | HWMON_F_ENABLE,
+ HWMON_F_FAULT | HWMON_F_ENABLE,
+ HWMON_F_FAULT | HWMON_F_ENABLE),
+ HWMON_CHANNEL_INFO(pwm,
+ HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
+ HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
+ HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
+ HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
+ HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
+ HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
+ HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
+ HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
+ NULL
+};
+
+static const struct hwmon_chip_info gxp_fan_ctrl_chip_info = {
+ .ops = &gxp_fan_ctrl_ops,
+ .info = gxp_fan_ctrl_info,
+
+};
+
+static struct regmap *gxp_fan_ctrl_init_regmap(struct platform_device *pdev, char *reg_name)
+{
+ struct regmap_config regmap_config = {
+ .reg_bits = 32,
+ .reg_stride = 4,
+ .val_bits = 32,
+ };
+ void __iomem *base;
+
+ base = devm_platform_ioremap_resource_byname(pdev, reg_name);
+ if (IS_ERR(base))
+ return ERR_CAST(base);
+
+ regmap_config.name = reg_name;
+
+ return devm_regmap_init_mmio(&pdev->dev, base, &regmap_config);
+}
+
+static int gxp_fan_ctrl_probe(struct platform_device *pdev)
+{
+ struct gxp_fan_ctrl_drvdata *drvdata;
+ struct resource *res;
+ struct device *dev = &pdev->dev;
+ int error;
+
+ drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gxp_fan_ctrl_drvdata),
+ GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ drvdata->dev = &pdev->dev;
+
+ platform_set_drvdata(pdev, drvdata);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ drvdata->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(drvdata->base)) {
+ error = dev_err_probe(dev, PTR_ERR(drvdata->base),
+ "failed to map base\n");
+ goto free_mem;
+ }
+ drvdata->plreg_map = gxp_fan_ctrl_init_regmap(pdev, "pl");
+ if (IS_ERR(drvdata->plreg_map)) {
+ error = dev_err_probe(dev, PTR_ERR(drvdata->plreg_map),
+ "failed to map plreg_handle\n");
+ goto free_mem;
+ }
+
+ drvdata->fn2_map = gxp_fan_ctrl_init_regmap(pdev, "fn2");
+ if (IS_ERR(drvdata->fn2_map)) {
+ error = dev_err_probe(dev, PTR_ERR(drvdata->fn2_map),
+ "failed to map fn2_handle\n");
+ goto free_mem;
+ }
+
+ drvdata->hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
+ "fan_ctrl",
+ drvdata,
+ &gxp_fan_ctrl_chip_info,
+ NULL);
+
+ if (IS_ERR(drvdata->hwmon_dev)) {
+ error = dev_err_probe(dev, PTR_ERR(drvdata->hwmon_dev),
+ "failed to register fan ctrl\n");
+
+ goto free_mem;
+ }
+
+ return 0;
+
+free_mem:
+ kfree(drvdata);
+ return error;
+}
+
+static const struct of_device_id gxp_fan_ctrl_of_match[] = {
+ { .compatible = "hpe,gxp-fan-ctrl", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, gxp_fan_ctrl_of_match);
+
+static struct platform_driver gxp_fan_ctrl_driver = {
+ .probe = gxp_fan_ctrl_probe,
+ .driver = {
+ .name = "gxp-fan-ctrl",
+ .of_match_table = gxp_fan_ctrl_of_match,
+ },
+};
+module_platform_driver(gxp_fan_ctrl_driver);
+
+MODULE_AUTHOR("Nick Hawkins <nick.hawkins@xxxxxxx>");
+MODULE_DESCRIPTION("HPE GXP fan controller");
+MODULE_LICENSE("GPL");
--
2.17.1