[PATCH v3 3/5] thermal: add support for the MCU controlled FAN on Khadas boards

Neil Armstrong
2020-06-08T09:18:08Z

The new Khadas VIM2 and VIM3 boards controls the cooling fan via the
on-board microcontroller.

This implements the FAN control as thermal devices and as cell of the Khadas
MCU MFD driver.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
drivers/thermal/Kconfig | 11 ++
drivers/thermal/Makefile | 1 +
drivers/thermal/khadas_mcu_fan.c | 174 +++++++++++++++++++++++++++++++
3 files changed, 186 insertions(+)
create mode 100644 drivers/thermal/khadas_mcu_fan.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 91af271e9bb0..53efd381f434 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -490,4 +490,15 @@ config SPRD_THERMAL
help
Support for the Spreadtrum thermal sensor driver in the Linux thermal
framework.
+
+config KHADAS_MCU_FAN_THERMAL
+ tristate "Khadas MCU controller FAN cooling support"
+ depends on OF || COMPILE_TEST
+ depends on MFD_KHADAS_MCU
+ select MFD_CORE
+ select REGMAP
+ help
+ If you say yes here you get support for the FAN controlled
+ by the Microcontroller found on the Khadas VIM boards.
+
endif
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 8c8ed7b79915..460428c2122c 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -60,3 +60,4 @@ obj-$(CONFIG_ZX2967_THERMAL) += zx2967_thermal.o
obj-$(CONFIG_UNIPHIER_THERMAL) += uniphier_thermal.o
obj-$(CONFIG_AMLOGIC_THERMAL) += amlogic_thermal.o
obj-$(CONFIG_SPRD_THERMAL) += sprd_thermal.o
+obj-$(CONFIG_KHADAS_MCU_FAN_THERMAL) += khadas_mcu_fan.o
diff --git a/drivers/thermal/khadas_mcu_fan.c b/drivers/thermal/khadas_mcu_fan.c
new file mode 100644
index 000000000000..6995b443cad4
--- /dev/null
+++ b/drivers/thermal/khadas_mcu_fan.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Khadas MCU Controlled FAN driver
+ *
+ * Copyright (C) 2020 BayLibre SAS
+ * Author(s): Neil Armstrong <narmstrong@baylibre.com>
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/khadas-mcu.h>
+#include <linux/regmap.h>
+#include <linux/sysfs.h>
+#include <linux/thermal.h>
+
+#define MAX_LEVEL 3
+
+struct khadas_mcu_fan_ctx {
+ struct khadas_mcu *mcu;
+ unsigned int level;
+ struct thermal_cooling_device *cdev;
+};
+
+static int khadas_mcu_fan_set_level(struct khadas_mcu_fan_ctx *ctx,
+ unsigned int level)
+{
+ int ret;
+
+ ret = regmap_write(ctx->mcu->regmap, KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG,
+ level);
+ if (ret)
+ return ret;
+
+ ctx->level = level;
+
+ return 0;
+}
+
+static int khadas_mcu_fan_get_max_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
+
+ if (!ctx)
+ return -EINVAL;
+
+ *state = MAX_LEVEL;
+
+ return 0;
+}
+
+static int khadas_mcu_fan_get_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
+
+ if (!ctx)
+ return -EINVAL;
+
+ *state = ctx->level;
+
+ return 0;
+}
+
+static int
+khadas_mcu_fan_set_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long state)
+{
+ struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
+
+ if (!ctx || (state > MAX_LEVEL))
+ return -EINVAL;
+
+ if (state == ctx->level)
+ return 0;
+
+ return khadas_mcu_fan_set_level(ctx, state);
+}
+
+static const struct thermal_cooling_device_ops khadas_mcu_fan_cooling_ops = {
+ .get_max_state = khadas_mcu_fan_get_max_state,
+ .get_cur_state = khadas_mcu_fan_get_cur_state,
+ .set_cur_state = khadas_mcu_fan_set_cur_state,
+};
+
+static int khadas_mcu_fan_probe(struct platform_device *pdev)
+{
+ struct khadas_mcu *mcu = dev_get_drvdata(pdev->dev.parent);
+ struct thermal_cooling_device *cdev;
+ struct device *dev = &pdev->dev;
+ struct khadas_mcu_fan_ctx *ctx;
+ int ret;
+
+ ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+ ctx->mcu = mcu;
+ platform_set_drvdata(pdev, ctx);
+
+ cdev = devm_thermal_of_cooling_device_register(dev->parent,
+ dev->parent->of_node, "khadas-mcu-fan", ctx,
+ &khadas_mcu_fan_cooling_ops);
+ if (IS_ERR(cdev)) {
+ ret = PTR_ERR(cdev);
+ dev_err(dev,
+ "Failed to register khadas-mcu-fan as cooling device: %d\n",
+ ret);
+ return ret;
+ }
+ ctx->cdev = cdev;
+ thermal_cdev_update(cdev);
+
+ return 0;
+}
+
+static int khadas_mcu_fan_disable(struct device *dev)
+{
+ struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
+ unsigned int level_save = ctx->level;
+ int ret;
+
+ ret = khadas_mcu_fan_set_level(ctx, 0);
+ if (ret)
+ return ret;
+
+ ctx->level = level_save;
+
+ return 0;
+}
+
+static void khadas_mcu_fan_shutdown(struct platform_device *pdev)
+{
+ khadas_mcu_fan_disable(&pdev->dev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int khadas_mcu_fan_suspend(struct device *dev)
+{
+ return khadas_mcu_fan_disable(dev);
+}
+
+static int khadas_mcu_fan_resume(struct device *dev)
+{
+ struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
+
+ return khadas_mcu_fan_set_level(ctx, ctx->level);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(khadas_mcu_fan_pm, khadas_mcu_fan_suspend,
+ khadas_mcu_fan_resume);
+
+static const struct platform_device_id khadas_mcu_fan_id_table[] = {
+ { .name = "khadas-mcu-fan-ctrl", },
+ {},
+};
+MODULE_DEVICE_TABLE(platform, khadas_mcu_fan_id_table);
+
+static struct platform_driver khadas_mcu_fan_driver = {
+ .probe = khadas_mcu_fan_probe,
+ .shutdown = khadas_mcu_fan_shutdown,
+ .driver = {
+ .name = "khadas-mcu-fan-ctrl",
+ .pm = &khadas_mcu_fan_pm,
+ },
+ .id_table = khadas_mcu_fan_id_table,
+};
+
+module_platform_driver(khadas_mcu_fan_driver);
+
+MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
+MODULE_DESCRIPTION("Khadas MCU FAN driver");
+MODULE_LICENSE("GPL");
--
2.22.0