drivers: thermal: Snapshot of lmh cpu VDD driver from msm-4.19

Add a snapshot of limits cpu voltage cooling device driver changes
from msm-4.19. This is snapshot as of 'commit <603750db5e89>
("drivers: thermal: validate cdev sysfs cur_state request before
using it")'.

Change-Id: I3e8763df4e0a715407b955939f3d91b6c10f976a
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>

drivers/thermal/qcom/Kconfig

@@ -172,3 +172,12 @@ config MAX31760_FAN_CONTROLLER
 	  This driver uses i2c bus to control registers for setting
 	  different fan speed. Also, this driver initializes the power for
 	  the fan controller.
+
+config QTI_LMH_CPU_VDD_COOLING_DEVICE
+	tristate "QTI CPU LMH VDD Voltage cooling devices"
+	depends on THERMAL_OF && QTI_THERMAL
+	help
+	   This enables the QTI limits hardware CPU VDD cooling devices.
+	   These cooling devices will be used by QTI chipset to place a
+	   request to limits hardware for a minimum CPU railway voltage
+	   corner at cold temperature condition.

drivers/thermal/qcom/Makefile

@@ -25,3 +25,4 @@ obj-$(CONFIG_QTI_RPM_SMD_COOLING_DEVICE) += rpm_smd_cooling_device.o
 obj-$(CONFIG_QTI_LIMITS_ISENSE_CDSP) += msm_isense_cdsp.o
 obj-$(CONFIG_QTI_DDR_COOLING_DEVICE) += ddr_cdev.o
 obj-$(CONFIG_MAX31760_FAN_CONTROLLER) += max31760_fan.o
+obj-$(CONFIG_QTI_LMH_CPU_VDD_COOLING_DEVICE) += lmh_cpu_vdd_cdev.o

drivers/thermal/qcom/lmh_cpu_vdd_cdev.c

@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019, 2021, The Linux Foundation. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "%s:%s " fmt, KBUILD_MODNAME, __func__
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+#include <linux/cpu_cooling.h>
+#include <linux/idr.h>
+
+#define LMH_CPU_VDD_MAX_LVL	1
+#define LIMITS_CLUSTER_MIN_FREQ_OFFSET	0x3C0
+
+struct lmh_cpu_vdd_cdev {
+	struct list_head node;
+	int id;
+	bool cpu_vdd_state;
+	void *min_freq_reg;
+	struct thermal_cooling_device *cdev;
+};
+
+static DEFINE_IDA(lmh_cpu_vdd_ida);
+static DEFINE_MUTEX(lmh_cpu_vdd_lock);
+static LIST_HEAD(lmh_cpu_vdd_list);
+
+static int lmh_cpu_vdd_set_cur_state(struct thermal_cooling_device *cdev,
+				 unsigned long state)
+{
+	struct lmh_cpu_vdd_cdev *vdd_cdev = cdev->devdata;
+
+	if (state > LMH_CPU_VDD_MAX_LVL)
+		return -EINVAL;
+
+	state = !!state;
+	/* Check if the old cooling action is same as new cooling action */
+	if (vdd_cdev->cpu_vdd_state == state)
+		return 0;
+
+	writel_relaxed(state, vdd_cdev->min_freq_reg);
+	vdd_cdev->cpu_vdd_state = state;
+
+	pr_debug("%s limits CPU VDD restriction for %s\n",
+		state ? "Triggered" : "Cleared", vdd_cdev->cdev->type);
+
+	return 0;
+}
+
+static int lmh_cpu_vdd_get_cur_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	struct lmh_cpu_vdd_cdev *lmh_cpu_vdd_cdev = cdev->devdata;
+
+	*state = (lmh_cpu_vdd_cdev->cpu_vdd_state) ?
+			LMH_CPU_VDD_MAX_LVL : 0;
+
+	return 0;
+}
+
+static int lmh_cpu_vdd_get_max_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	*state = LMH_CPU_VDD_MAX_LVL;
+	return 0;
+}
+
+static struct thermal_cooling_device_ops lmh_cpu_vdd_cooling_ops = {
+	.get_max_state = lmh_cpu_vdd_get_max_state,
+	.get_cur_state = lmh_cpu_vdd_get_cur_state,
+	.set_cur_state = lmh_cpu_vdd_set_cur_state,
+};
+
+
+static int lmh_cpu_vdd_probe(struct platform_device *pdev)
+{
+	int ret = -1;
+	struct lmh_cpu_vdd_cdev *lmh_cpu_vdd_cdev;
+	struct device_node *dn = pdev->dev.of_node;
+	uint32_t min_reg;
+	char cdev_name[THERMAL_NAME_LENGTH] = "";
+	const __be32 *addr;
+
+	lmh_cpu_vdd_cdev = devm_kzalloc(&pdev->dev, sizeof(*lmh_cpu_vdd_cdev),
+					GFP_KERNEL);
+	if (!lmh_cpu_vdd_cdev)
+		return -ENOMEM;
+
+	addr = of_get_address(dn, 0, NULL, NULL);
+	if (!addr) {
+		dev_err(&pdev->dev, "Property llm-base-addr not found\n");
+		return -EINVAL;
+	}
+
+	min_reg = be32_to_cpu(addr[0]) + LIMITS_CLUSTER_MIN_FREQ_OFFSET;
+	lmh_cpu_vdd_cdev->min_freq_reg = devm_ioremap(&pdev->dev, min_reg, 0x4);
+	if (!lmh_cpu_vdd_cdev->min_freq_reg) {
+		dev_err(&pdev->dev, "lmh cpu vdd register remap failed\n");
+		return -ENOMEM;
+	}
+
+	mutex_lock(&lmh_cpu_vdd_lock);
+	ret = ida_simple_get(&lmh_cpu_vdd_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to create ida\n");
+		goto unlock_exit;
+	}
+	lmh_cpu_vdd_cdev->id = ret;
+	ret = 0;
+
+	snprintf(cdev_name, THERMAL_NAME_LENGTH, "lmh-cpu-vdd%d",
+			lmh_cpu_vdd_cdev->id);
+
+	lmh_cpu_vdd_cdev->cdev = thermal_of_cooling_device_register(
+					dn,
+					cdev_name,
+					lmh_cpu_vdd_cdev,
+					&lmh_cpu_vdd_cooling_ops);
+	if (IS_ERR(lmh_cpu_vdd_cdev->cdev)) {
+		ret = PTR_ERR(lmh_cpu_vdd_cdev->cdev);
+		dev_err(&pdev->dev, "Cooling register failed for %s, ret:%d\n",
+			cdev_name, ret);
+		lmh_cpu_vdd_cdev->cdev = NULL;
+		goto remove_ida;
+	}
+	list_add(&lmh_cpu_vdd_cdev->node, &lmh_cpu_vdd_list);
+	mutex_unlock(&lmh_cpu_vdd_lock);
+
+	pr_debug("Cooling device [%s] registered.\n", cdev_name);
+
+	return ret;
+
+remove_ida:
+	ida_simple_remove(&lmh_cpu_vdd_ida, lmh_cpu_vdd_cdev->id);
+
+unlock_exit:
+	mutex_unlock(&lmh_cpu_vdd_lock);
+
+	return ret;
+}
+
+static int lmh_cpu_vdd_remove(struct platform_device *pdev)
+{
+	struct lmh_cpu_vdd_cdev *lmh_cpu_vdd, *c_next;
+
+	mutex_lock(&lmh_cpu_vdd_lock);
+	list_for_each_entry_safe(lmh_cpu_vdd, c_next,
+			&lmh_cpu_vdd_list, node) {
+		if (lmh_cpu_vdd->cdev) {
+			thermal_cooling_device_unregister(
+				lmh_cpu_vdd->cdev);
+			lmh_cpu_vdd->cdev = NULL;
+		}
+		ida_simple_remove(&lmh_cpu_vdd_ida, lmh_cpu_vdd->id);
+		list_del(&lmh_cpu_vdd->node);
+	}
+	mutex_unlock(&lmh_cpu_vdd_lock);
+
+	return 0;
+}
+static const struct of_device_id lmh_cpu_vdd_match[] = {
+	{ .compatible = "qcom,lmh-cpu-vdd", },
+	{},
+};
+
+static struct platform_driver lmh_cpu_vdd_driver = {
+	.probe		= lmh_cpu_vdd_probe,
+	.remove         = lmh_cpu_vdd_remove,
+	.driver		= {
+		.name = KBUILD_MODNAME,
+		.of_match_table = lmh_cpu_vdd_match,
+	},
+};
+builtin_platform_driver(lmh_cpu_vdd_driver);
+MODULE_LICENSE("GPL v2");