1 files changed, 134 insertions, 0 deletions
diff --git a/drivers/cpuidle/lpm-workarounds.c b/drivers/cpuidle/lpm-workarounds.c
new file mode 100644
index 000000000000..104def7e71e4
--- /dev/null
+++ b/drivers/cpuidle/lpm-workarounds.c
@@ -0,0 +1,134 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/regulator/rpm-smd-regulator.h>
+
+static struct regulator *lpm_cx_reg;
+static struct work_struct dummy_vote_work;
+static struct workqueue_struct *lpm_wa_wq;
+static bool lpm_wa_cx_turbo_unvote;
+
+/* While exiting from RPM assisted power collapse on some targets like MSM8939
+ * the CX is bumped to turbo mode by RPM. To reduce the power impact, APSS
+ * low power driver need to remove the CX turbo vote.
+ */
+static void send_dummy_cx_vote(struct work_struct *w)
+{
+	if (lpm_cx_reg) {
+		regulator_set_voltage(lpm_cx_reg,
+			RPM_REGULATOR_CORNER_SUPER_TURBO,
+			RPM_REGULATOR_CORNER_SUPER_TURBO);
+
+		regulator_set_voltage(lpm_cx_reg,
+			RPM_REGULATOR_CORNER_NONE,
+			RPM_REGULATOR_CORNER_SUPER_TURBO);
+	}
+}
+
+/*
+ * lpm_wa_cx_unvote_send(): Unvote for CX turbo mode
+ */
+void lpm_wa_cx_unvote_send(void)
+{
+	if (lpm_wa_cx_turbo_unvote)
+		queue_work(lpm_wa_wq, &dummy_vote_work);
+}
+EXPORT_SYMBOL(lpm_wa_cx_unvote_send);
+
+static int lpm_wa_cx_unvote_init(struct platform_device *pdev)
+{
+	int ret = 0;
+
+	lpm_cx_reg = devm_regulator_get(&pdev->dev, "lpm-cx");
+	if (IS_ERR(lpm_cx_reg)) {
+		ret = PTR_ERR(lpm_cx_reg);
+		if (ret != -EPROBE_DEFER)
+			pr_err("Unable to get the CX regulator\n");
+		return ret;
+	}
+
+	INIT_WORK(&dummy_vote_work, send_dummy_cx_vote);
+
+	lpm_wa_wq = alloc_workqueue("lpm-wa",
+				WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_HIGHPRI, 1);
+
+	return ret;
+}
+
+static int lpm_wa_cx_unvote_exit(void)
+{
+	if (lpm_wa_wq)
+		destroy_workqueue(lpm_wa_wq);
+
+	return 0;
+}
+
+static int lpm_wa_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+
+	lpm_wa_cx_turbo_unvote = of_property_read_bool(pdev->dev.of_node,
+					"qcom,lpm-wa-cx-turbo-unvote");
+	if (lpm_wa_cx_turbo_unvote) {
+		ret = lpm_wa_cx_unvote_init(pdev);
+		if (ret) {
+			pr_err("%s: Failed to initialize lpm_wa_cx_unvote (%d)\n",
+				__func__, ret);
+			return ret;
+		}
+	}
+
+	return ret;
+}
+
+static int lpm_wa_remove(struct platform_device *pdev)
+{
+	int ret = 0;
+	if (lpm_wa_cx_turbo_unvote)
+		ret = lpm_wa_cx_unvote_exit();
+
+	return ret;
+}
+
+static struct of_device_id lpm_wa_mtch_tbl[] = {
+	{.compatible = "qcom,lpm-workarounds"},
+	{},
+};
+
+static struct platform_driver lpm_wa_driver = {
+	.probe = lpm_wa_probe,
+	.remove = lpm_wa_remove,
+	.driver = {
+		.name = "lpm-workarounds",
+		.owner = THIS_MODULE,
+		.of_match_table = lpm_wa_mtch_tbl,
+	},
+};
+
+static int __init lpm_wa_module_init(void)
+{
+	int ret;
+	ret = platform_driver_register(&lpm_wa_driver);
+	if (ret)
+		pr_info("Error registering %s\n", lpm_wa_driver.driver.name);
+
+	return ret;
+}
+late_initcall(lpm_wa_module_init);