[PATCH v2 4/5] hwmon: (gxp_fan_ctrl) Provide fan info via gpio

[nick . hawkins]

From: Nick Hawkins <nick.hawkins@xxxxxxx>

The fan driver now receives fan data from GPIO via a shared variable.
This is a necessity as the Host and the driver need access to the same
information. Part of the changes includes removing a system power check
as the GPIO driver needs it to report power state to host.

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

---

v2:
 *Removed use of shared functions to GPIO in favor of a shared variable
 *Added build dependency on GXP GPIO driver.
---
 drivers/hwmon/Kconfig        |  2 +-
 drivers/hwmon/gxp-fan-ctrl.c | 61 +++++-------------------------------
 drivers/hwmon/gxp-gpio.h     | 13 ++++++++
 3 files changed, 21 insertions(+), 55 deletions(-)
 create mode 100644 drivers/hwmon/gxp-gpio.h

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 5b3b76477b0e..5c606bea31f9 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -716,7 +716,7 @@ config SENSORS_GPIO_FAN
 
 config SENSORS_GXP_FAN_CTRL
 	tristate "HPE GXP fan controller"
-	depends on ARCH_HPE_GXP || COMPILE_TEST
+	depends on (ARCH_HPE_GXP  && GPIO_GXP_PL) || COMPILE_TEST
 	help
 	  If you say yes here you get support for GXP fan control functionality.
 
diff --git a/drivers/hwmon/gxp-fan-ctrl.c b/drivers/hwmon/gxp-fan-ctrl.c
index 0014b8b0fd41..8555231328d7 100644
--- a/drivers/hwmon/gxp-fan-ctrl.c
+++ b/drivers/hwmon/gxp-fan-ctrl.c
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */
+/* Copyright (C) 2023 Hewlett-Packard Enterprise Development Company, L.P. */
 
 #include <linux/bits.h>
 #include <linux/err.h>
@@ -8,51 +8,28 @@
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include "gxp-gpio.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 {
-	void __iomem	*base;
-	void __iomem	*plreg;
-	void __iomem	*fn2;
+	void __iomem *base;
 };
 
 static bool fan_installed(struct device *dev, int fan)
 {
-	struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
-	u8 val;
-
-	val = readb(drvdata->plreg + OFS_FAN_INST);
-
-	return !!(val & BIT(fan));
+	return !!(fan_presence & BIT(fan));
 }
 
 static long fan_failed(struct device *dev, int fan)
 {
-	struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
-	u8 val;
-
-	val = readb(drvdata->plreg + OFS_FAN_FAIL);
-
-	return !!(val & BIT(fan));
+	return !!(fan_fail & BIT(fan));
 }
 
 static long fan_enabled(struct device *dev, int fan)
 {
-	struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
-	u32 val;
-
-	/*
-	 * Check the power status as if the platform is off the value
-	 * reported for the PWM will be incorrect. Report fan as
-	 * disabled.
-	 */
-	val = readl(drvdata->fn2 + OFS_SEVSTAT);
-
-	return !!((val & BIT(POWER_BIT)) && fan_installed(dev, fan));
+	return !!(fan_installed(dev, fan));
 }
 
 static int gxp_pwm_write(struct device *dev, u32 attr, int channel, long val)
@@ -98,20 +75,8 @@ static int gxp_fan_read(struct device *dev, u32 attr, int channel, long *val)
 static int gxp_pwm_read(struct device *dev, u32 attr, int channel, long *val)
 {
 	struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
-	u32 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.
-	 */
-
-	reg = readl(drvdata->fn2 + OFS_SEVSTAT);
-
-	if (reg & BIT(POWER_BIT))
-		*val = fan_installed(dev, channel) ? readb(drvdata->base + channel) : 0;
-	else
-		*val = 0;
+	*val = fan_installed(dev, channel) ? readb(drvdata->base + channel) : 0;
 
 	return 0;
 }
@@ -212,18 +177,6 @@ static int gxp_fan_ctrl_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, PTR_ERR(drvdata->base),
 				     "failed to map base\n");
 
-	drvdata->plreg = devm_platform_ioremap_resource_byname(pdev,
-							       "pl");
-	if (IS_ERR(drvdata->plreg))
-		return dev_err_probe(dev, PTR_ERR(drvdata->plreg),
-				     "failed to map plreg\n");
-
-	drvdata->fn2 = devm_platform_ioremap_resource_byname(pdev,
-							     "fn2");
-	if (IS_ERR(drvdata->fn2))
-		return dev_err_probe(dev, PTR_ERR(drvdata->fn2),
-				     "failed to map fn2\n");
-
 	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
 							 "hpe_gxp_fan_ctrl",
 							 drvdata,
diff --git a/drivers/hwmon/gxp-gpio.h b/drivers/hwmon/gxp-gpio.h
new file mode 100644
index 000000000000..88abe60bbe83
--- /dev/null
+++ b/drivers/hwmon/gxp-gpio.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (C) 2023 Hewlett-Packard Enterprise Development Company, L.P. */
+
+#ifndef __GPIO_GXP_H__
+#define __GPIO_GXP_H__
+
+#include <linux/err.h>
+
+/* Data provided by GPIO */
+extern u8 fan_presence;
+extern u8 fan_fail;
+
+#endif /* __GPIO_GXP_H__ */
-- 
2.17.1