PM / devfreq: Add devfreq driver for simple device

This is a snapshot of the simple devfreq device driver as of msm-3.10
commit:

acdce027751d5a7488b283f0ce3111f873a5816d (Merge "defconfig: arm64:
Enable ONESHOT_SYNC for msm8994")

Signed-off-by: Kumar Gala <galak@codeaurora.org>
[junjiew@codeaurora.org: resolved conflicts]
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>

Change-Id: I37f1781d9192dd0ad2797ea52f9bd3a5ea5847b0

drivers/devfreq/Kconfig

@@ -106,6 +106,16 @@ config ARM_TEGRA_DEVFREQ
          It reads ACTMON counters of memory controllers and adjusts the
          operating frequencies and voltages with OPP support.
 
+config DEVFREQ_SIMPLE_DEV
+	tristate "Device driver for simple clock device with no status info"
+	select DEVFREQ_GOV_PERFORMANCE
+	select DEVFREQ_GOV_POWERSAVE
+	select DEVFREQ_GOV_USERSPACE
+	select DEVFREQ_GOV_CPUFREQ
+	help
+	  Device driver for simple devices that control their frequency using
+	  clock APIs and don't have any form of status reporting.
+
 source "drivers/devfreq/event/Kconfig"
 
 endif # PM_DEVFREQ

drivers/devfreq/Makefile

@@ -10,6 +10,7 @@ obj-$(CONFIG_DEVFREQ_GOV_QCOM_ADRENO_TZ) += governor_msm_adreno_tz.o
 obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos/
 obj-$(CONFIG_ARM_EXYNOS5_BUS_DEVFREQ)	+= exynos/
 obj-$(CONFIG_ARM_TEGRA_DEVFREQ)		+= tegra-devfreq.o
+obj-$(CONFIG_DEVFREQ_SIMPLE_DEV)	+= devfreq_simple_dev.o
 
 # DEVFREQ Event Drivers
 obj-$(CONFIG_PM_DEVFREQ_EVENT)		+= event/

drivers/devfreq/devfreq_simple_dev.c

@@ -0,0 +1,193 @@
+/*
+ * 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.
+ */
+
+#define pr_fmt(fmt) "devfreq-simple-dev: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/ktime.h>
+#include <linux/time.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/devfreq.h>
+#include <linux/of.h>
+#include <linux/clk.h>
+#include <trace/events/power.h>
+
+struct dev_data {
+	struct clk *clk;
+	struct devfreq *df;
+	struct devfreq_dev_profile profile;
+};
+
+static void find_freq(struct devfreq_dev_profile *p, unsigned long *freq,
+			u32 flags)
+{
+	int i;
+	unsigned long atmost, atleast, f;
+
+	atmost = p->freq_table[0];
+	atleast = p->freq_table[p->max_state-1];
+	for (i = 0; i < p->max_state; i++) {
+		f = p->freq_table[i];
+		if (f <= *freq)
+			atmost = max(f, atmost);
+		if (f >= *freq)
+			atleast = min(f, atleast);
+	}
+
+	if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND)
+		*freq = atmost;
+	else
+		*freq = atleast;
+}
+
+static int dev_target(struct device *dev, unsigned long *freq, u32 flags)
+{
+	struct dev_data *d = dev_get_drvdata(dev);
+
+	find_freq(&d->profile, freq, flags);
+	return clk_set_rate(d->clk, *freq * 1000);
+}
+
+static int dev_get_cur_freq(struct device *dev, unsigned long *freq)
+{
+	struct dev_data *d = dev_get_drvdata(dev);
+	unsigned long f;
+
+	f = clk_get_rate(d->clk);
+	if (IS_ERR_VALUE(f))
+		return f;
+	*freq = f / 1000;
+	return 0;
+}
+
+#define PROP_TBL "freq-tbl-khz"
+static int devfreq_clock_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dev_data *d;
+	struct devfreq_dev_profile *p;
+	u32 *data, poll;
+	const char *gov_name;
+	int ret, len, i, j;
+	unsigned long f;
+
+	d = devm_kzalloc(dev, sizeof(*d), GFP_KERNEL);
+	if (!d)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, d);
+
+	d->clk = devm_clk_get(dev, "devfreq_clk");
+	if (IS_ERR(d->clk))
+		return PTR_ERR(d->clk);
+
+	if (!of_find_property(dev->of_node, PROP_TBL, &len))
+		return -EINVAL;
+
+	len /= sizeof(*data);
+	data = devm_kzalloc(dev, len * sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	p = &d->profile;
+	p->freq_table = devm_kzalloc(dev, len * sizeof(*p->freq_table),
+				     GFP_KERNEL);
+	if (!p->freq_table)
+		return -ENOMEM;
+
+	ret = of_property_read_u32_array(dev->of_node, PROP_TBL, data, len);
+	if (ret)
+		return ret;
+
+	j = 0;
+	for (i = 0; i < len; i++) {
+		f = clk_round_rate(d->clk, data[i] * 1000);
+		if (IS_ERR_VALUE(f))
+			dev_warn(dev, "Unable to find dev rate for %d KHz",
+				 data[i]);
+		else
+			p->freq_table[j++] = f / 1000;
+	}
+	p->max_state = j;
+	devm_kfree(dev, data);
+
+	if (p->max_state == 0) {
+		dev_err(dev, "Error parsing property %s!\n", PROP_TBL);
+		return -EINVAL;
+	}
+
+	p->target = dev_target;
+	p->get_cur_freq = dev_get_cur_freq;
+	ret = dev_get_cur_freq(dev, &p->initial_freq);
+	if (ret)
+		return ret;
+
+	p->polling_ms = 50;
+	if (!of_property_read_u32(dev->of_node, "polling-ms", &poll))
+		p->polling_ms = poll;
+
+	if (of_property_read_string(dev->of_node, "governor", &gov_name))
+		gov_name = "performance";
+
+
+	d->df = devfreq_add_device(dev, p, gov_name, NULL);
+	if (IS_ERR(d->df))
+		return PTR_ERR(d->df);
+
+	return 0;
+}
+
+static int devfreq_clock_remove(struct platform_device *pdev)
+{
+	struct dev_data *d = platform_get_drvdata(pdev);
+	devfreq_remove_device(d->df);
+	return 0;
+}
+
+static struct of_device_id match_table[] = {
+	{ .compatible = "devfreq-simple-dev" },
+	{}
+};
+
+static struct platform_driver devfreq_clock_driver = {
+	.probe = devfreq_clock_probe,
+	.remove = devfreq_clock_remove,
+	.driver = {
+		.name = "devfreq-simple-dev",
+		.of_match_table = match_table,
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init devfreq_clock_init(void)
+{
+	platform_driver_register(&devfreq_clock_driver);
+	return 0;
+}
+device_initcall(devfreq_clock_init);
+
+static void __exit devfreq_clock_exit(void)
+{
+	platform_driver_unregister(&devfreq_clock_driver);
+}
+module_exit(devfreq_clock_exit);
+
+MODULE_DESCRIPTION("Devfreq driver for setting generic device clock frequency");
+MODULE_LICENSE("GPL v2");