--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * rpi-poe-fan.c - Hwmon driver for Raspberry Pi PoE HAT fan.
+ *
+ * Copyright (C) 2018 Raspberry Pi (Trading) Ltd.
+ * Based on pwm-fan.c by Kamil Debski <k.debski@samsung.com>
+ *
+ * Author: Serge Schneider <serge@raspberrypi.org>
+ */
+
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/sysfs.h>
+#include <linux/thermal.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define MAX_PWM 255
+
+#define POE_CUR_PWM 0x0
+#define POE_DEF_PWM 0x1
+
+struct rpi_poe_fan_ctx {
+ struct mutex lock;
+ struct rpi_firmware *fw;
+ unsigned int pwm_value;
+ unsigned int def_pwm_value;
+ unsigned int rpi_poe_fan_state;
+ unsigned int rpi_poe_fan_max_state;
+ unsigned int *rpi_poe_fan_cooling_levels;
+ struct thermal_cooling_device *cdev;
+ struct notifier_block nb;
+};
+
+struct fw_tag_data_s{
+ u32 reg;
+ u32 val;
+ u32 ret;
+};
+
+static int write_reg(struct rpi_firmware *fw, u32 reg, u32 *val){
+ struct fw_tag_data_s fw_tag_data = {
+ .reg = reg,
+ .val = *val
+ };
+ int ret;
+ ret = rpi_firmware_property(fw, RPI_FIRMWARE_SET_POE_HAT_VAL,
+ &fw_tag_data, sizeof(fw_tag_data));
+ if (ret) {
+ return ret;
+ } else if (fw_tag_data.ret) {
+ return -EIO;
+ }
+ return 0;
+}
+
+static int read_reg(struct rpi_firmware *fw, u32 reg, u32 *val){
+ struct fw_tag_data_s fw_tag_data = {
+ .reg = reg,
+ };
+ int ret;
+ ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_POE_HAT_VAL,
+ &fw_tag_data, sizeof(fw_tag_data));
+ if (ret) {
+ return ret;
+ } else if (fw_tag_data.ret) {
+ return -EIO;
+ }
+ *val = fw_tag_data.val;
+ return 0;
+}
+
+static int rpi_poe_reboot(struct notifier_block *nb, unsigned long code,
+ void *unused)
+{
+ struct rpi_poe_fan_ctx *ctx = container_of(nb, struct rpi_poe_fan_ctx,
+ nb);
+
+ if (ctx->pwm_value != ctx->def_pwm_value)
+ write_reg(ctx->fw, POE_CUR_PWM, &ctx->def_pwm_value);
+
+ return NOTIFY_DONE;
+}
+
+static int __set_pwm(struct rpi_poe_fan_ctx *ctx, u32 pwm)
+{
+ int ret = 0;
+
+ mutex_lock(&ctx->lock);
+ if (ctx->pwm_value == pwm)
+ goto exit_set_pwm_err;
+
+ ret = write_reg(ctx->fw, POE_CUR_PWM, &pwm);
+ if (!ret)
+ ctx->pwm_value = pwm;
+exit_set_pwm_err:
+ mutex_unlock(&ctx->lock);
+ return ret;
+}
+
+static int __set_def_pwm(struct rpi_poe_fan_ctx *ctx, u32 def_pwm)
+{
+ int ret = 0;
+ mutex_lock(&ctx->lock);
+ if (ctx->def_pwm_value == def_pwm)
+ goto exit_set_def_pwm_err;
+
+ ret = write_reg(ctx->fw, POE_DEF_PWM, &def_pwm);
+ if (!ret)
+ ctx->def_pwm_value = def_pwm;
+exit_set_def_pwm_err:
+ mutex_unlock(&ctx->lock);
+ return ret;
+}
+
+static void rpi_poe_fan_update_state(struct rpi_poe_fan_ctx *ctx,
+ unsigned long pwm)
+{
+ int i;
+
+ for (i = 0; i < ctx->rpi_poe_fan_max_state; ++i)
+ if (pwm < ctx->rpi_poe_fan_cooling_levels[i + 1])
+ break;
+
+ ctx->rpi_poe_fan_state = i;
+}
+
+static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct rpi_poe_fan_ctx *ctx = dev_get_drvdata(dev);
+ unsigned long pwm;
+ int ret;
+
+ if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM)
+ return -EINVAL;
+
+ ret = __set_pwm(ctx, pwm);
+ if (ret)
+ return ret;
+
+ rpi_poe_fan_update_state(ctx, pwm);
+ return count;
+}
+
+static ssize_t set_def_pwm(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct rpi_poe_fan_ctx *ctx = dev_get_drvdata(dev);
+ unsigned long def_pwm;
+ int ret;
+
+ if (kstrtoul(buf, 10, &def_pwm) || def_pwm > MAX_PWM)
+ return -EINVAL;
+
+ ret = __set_def_pwm(ctx, def_pwm);
+ if (ret)
+ return ret;
+ return count;
+}
+
+static ssize_t show_pwm(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rpi_poe_fan_ctx *ctx = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", ctx->pwm_value);
+}
+
+static ssize_t show_def_pwm(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rpi_poe_fan_ctx *ctx = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", ctx->def_pwm_value);
+}
+
+
+static SENSOR_DEVICE_ATTR(pwm1, 0644, show_pwm, set_pwm, 0);
+static SENSOR_DEVICE_ATTR(def_pwm1, 0644, show_def_pwm, set_def_pwm, 1);
+
+static struct attribute *rpi_poe_fan_attrs[] = {
+ &sensor_dev_attr_pwm1.dev_attr.attr,
+ &sensor_dev_attr_def_pwm1.dev_attr.attr,
+ NULL,
+};
+
+ATTRIBUTE_GROUPS(rpi_poe_fan);
+
+/* thermal cooling device callbacks */
+static int rpi_poe_fan_get_max_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct rpi_poe_fan_ctx *ctx = cdev->devdata;
+
+ if (!ctx)
+ return -EINVAL;
+
+ *state = ctx->rpi_poe_fan_max_state;
+
+ return 0;
+}
+
+static int rpi_poe_fan_get_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct rpi_poe_fan_ctx *ctx = cdev->devdata;
+
+ if (!ctx)
+ return -EINVAL;
+
+ *state = ctx->rpi_poe_fan_state;
+
+ return 0;
+}
+
+static int rpi_poe_fan_set_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long state)
+{
+ struct rpi_poe_fan_ctx *ctx = cdev->devdata;
+ int ret;
+
+ if (!ctx || (state > ctx->rpi_poe_fan_max_state))
+ return -EINVAL;
+
+ if (state == ctx->rpi_poe_fan_state)
+ return 0;
+
+ ret = __set_pwm(ctx, ctx->rpi_poe_fan_cooling_levels[state]);
+ if (ret) {
+ dev_err(&cdev->device, "Cannot set pwm!\n");
+ return ret;
+ }
+
+ ctx->rpi_poe_fan_state = state;
+
+ return ret;
+}
+
+static const struct thermal_cooling_device_ops rpi_poe_fan_cooling_ops = {
+ .get_max_state = rpi_poe_fan_get_max_state,
+ .get_cur_state = rpi_poe_fan_get_cur_state,
+ .set_cur_state = rpi_poe_fan_set_cur_state,
+};
+
+static int rpi_poe_fan_of_get_cooling_data(struct device *dev,
+ struct rpi_poe_fan_ctx *ctx)
+{
+ struct device_node *np = dev->of_node;
+ int num, i, ret;
+
+ if (!of_find_property(np, "cooling-levels", NULL))
+ return 0;
+
+ ret = of_property_count_u32_elems(np, "cooling-levels");
+ if (ret <= 0) {
+ dev_err(dev, "cooling-levels property missing or invalid: %d\n",
+ ret);
+ return ret ? : -EINVAL;
+ }
+
+ num = ret;
+ ctx->rpi_poe_fan_cooling_levels = devm_kzalloc(dev, num * sizeof(u32),
+ GFP_KERNEL);
+ if (!ctx->rpi_poe_fan_cooling_levels)
+ return -ENOMEM;
+
+ ret = of_property_read_u32_array(np, "cooling-levels",
+ ctx->rpi_poe_fan_cooling_levels, num);
+ if (ret) {
+ dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
+ return ret;
+ }
+
+ for (i = 0; i < num; i++) {
+ if (ctx->rpi_poe_fan_cooling_levels[i] > MAX_PWM) {
+ dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
+ ctx->rpi_poe_fan_cooling_levels[i], MAX_PWM);
+ return -EINVAL;
+ }
+ }
+
+ ctx->rpi_poe_fan_max_state = num - 1;
+
+ return 0;
+}
+
+static int rpi_poe_fan_probe(struct platform_device *pdev)
+{
+ struct thermal_cooling_device *cdev;
+ struct rpi_poe_fan_ctx *ctx;
+ struct device *hwmon;
+ struct device_node *np = pdev->dev.of_node;
+ struct device_node *fw_node;
+ int ret;
+
+ fw_node = of_parse_phandle(np, "firmware", 0);
+ if (!fw_node) {
+ dev_err(&pdev->dev, "Missing firmware node\n");
+ return -ENOENT;
+ }
+
+ ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ mutex_init(&ctx->lock);
+
+ ctx->fw = rpi_firmware_get(fw_node);
+ if (!ctx->fw)
+ return -EPROBE_DEFER;
+
+ platform_set_drvdata(pdev, ctx);
+
+ ctx->nb.notifier_call = rpi_poe_reboot;
+ ret = register_reboot_notifier(&ctx->nb);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to register reboot notifier: %i\n",
+ ret);
+ return ret;
+ }
+ ret = read_reg(ctx->fw, POE_DEF_PWM, &ctx->def_pwm_value);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to get default PWM value: %i\n",
+ ret);
+ goto err;
+ }
+ ret = read_reg(ctx->fw, POE_CUR_PWM, &ctx->pwm_value);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to get current PWM value: %i\n",
+ ret);
+ goto err;
+ }
+
+ hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "rpipoefan",
+ ctx, rpi_poe_fan_groups);
+ if (IS_ERR(hwmon)) {
+ dev_err(&pdev->dev, "Failed to register hwmon device\n");
+ ret = PTR_ERR(hwmon);
+ goto err;
+ }
+
+ ret = rpi_poe_fan_of_get_cooling_data(&pdev->dev, ctx);
+ if (ret)
+ return ret;
+
+ rpi_poe_fan_update_state(ctx, ctx->pwm_value);
+ if (!IS_ENABLED(CONFIG_THERMAL))
+ return 0;
+
+ cdev = thermal_of_cooling_device_register(np,
+ "rpi-poe-fan", ctx,
+ &rpi_poe_fan_cooling_ops);
+ if (IS_ERR(cdev)) {
+ dev_err(&pdev->dev,
+ "Failed to register rpi-poe-fan as cooling device");
+ ret = PTR_ERR(cdev);
+ goto err;
+ }
+ ctx->cdev = cdev;
+ thermal_cdev_update(cdev);
+
+ return 0;
+err:
+ unregister_reboot_notifier(&ctx->nb);
+ return ret;
+}
+
+static int rpi_poe_fan_remove(struct platform_device *pdev)
+{
+ struct rpi_poe_fan_ctx *ctx = platform_get_drvdata(pdev);
+ u32 value = ctx->def_pwm_value;
+
+ unregister_reboot_notifier(&ctx->nb);
+ thermal_cooling_device_unregister(ctx->cdev);
+ if (ctx->pwm_value != value) {
+ write_reg(ctx->fw, POE_CUR_PWM, &value);
+ }
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int rpi_poe_fan_suspend(struct device *dev)
+{
+ struct rpi_poe_fan_ctx *ctx = dev_get_drvdata(dev);
+ u32 value = 0;
+ int ret = 0;
+
+ if (ctx->pwm_value != value)
+ ret = write_reg(ctx->fw, POE_CUR_PWM, &value);
+ return ret;
+}
+
+static int rpi_poe_fan_resume(struct device *dev)
+{
+ struct rpi_poe_fan_ctx *ctx = dev_get_drvdata(dev);
+ u32 value = ctx->pwm_value;
+ int ret = 0;
+
+ if (value != 0)
+ ret = write_reg(ctx->fw, POE_CUR_PWM, &value);
+
+ return ret;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(rpi_poe_fan_pm, rpi_poe_fan_suspend,
+ rpi_poe_fan_resume);
+
+static const struct of_device_id of_rpi_poe_fan_match[] = {
+ { .compatible = "raspberrypi,rpi-poe-fan", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, of_rpi_poe_fan_match);
+
+static struct platform_driver rpi_poe_fan_driver = {
+ .probe = rpi_poe_fan_probe,
+ .remove = rpi_poe_fan_remove,
+ .driver = {
+ .name = "rpi-poe-fan",
+ .pm = &rpi_poe_fan_pm,
+ .of_match_table = of_rpi_poe_fan_match,
+ },
+};
+
+module_platform_driver(rpi_poe_fan_driver);
+
+MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>");
+MODULE_ALIAS("platform:rpi-poe-fan");
+MODULE_DESCRIPTION("Raspberry Pi PoE HAT fan driver");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-rpi.git / commitdiff