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

From: nick.hawkins@hpe.com
To: jdelvare@suse.com, linux@roeck-us.net, robh+dt@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, verdun@hpe.com,
	nick.hawkins@hpe.com, corbet@lwn.net, linux@armlinux.org.uk,
	linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/6] hwmon: (gxp-fan-ctrl) Add GXP fan controller
Date: Mon, 28 Nov 2022 17:02:14 -0600	[thread overview]
Message-ID: <20221128230219.39537-2-nick.hawkins@hpe.com> (raw)
In-Reply-To: <20221128230219.39537-1-nick.hawkins@hpe.com>

From: Nick Hawkins <nick.hawkins@hpe.com>

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@hpe.com>

---

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@hpe.com>
+
+
+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@hpe.com>");
+MODULE_DESCRIPTION("HPE GXP fan controller");
+MODULE_LICENSE("GPL");
-- 
2.17.1

