[Blackfin] arch: Functional power management support: Add CPU and platform voltage scaling support

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

1 files changed, 137 insertions, 0 deletions

diff --git a/arch/blackfin/mach-common/dpmc.c b/arch/blackfin/mach-common/dpmc.c
new file mode 100644
index 000000000000..02c7efd1bcf4
--- /dev/null
+++ b/arch/blackfin/mach-common/dpmc.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright 2008 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/cpufreq.h>
+
+#include <asm/delay.h>
+#include <asm/dpmc.h>
+
+#define DRIVER_NAME "bfin dpmc"
+
+#define dprintk(msg...) \
+	cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, DRIVER_NAME, msg)
+
+struct bfin_dpmc_platform_data *pdata;
+
+/**
+ *	bfin_set_vlev - Update VLEV field in VR_CTL Reg.
+ *			Avoid BYPASS sequence
+ */
+static void bfin_set_vlev(unsigned int vlev)
+{
+	unsigned pll_lcnt;
+
+	pll_lcnt = bfin_read_PLL_LOCKCNT();
+
+	bfin_write_PLL_LOCKCNT(1);
+	bfin_write_VR_CTL((bfin_read_VR_CTL() & ~VLEV) | vlev);
+	bfin_write_PLL_LOCKCNT(pll_lcnt);
+}
+
+/**
+ *	bfin_get_vlev - Get CPU specific VLEV from platform device data
+ */
+static unsigned int bfin_get_vlev(unsigned int freq)
+{
+	int i;
+
+	if (!pdata)
+		goto err_out;
+
+	freq >>= 16;
+
+	for (i = 0; i < pdata->tabsize; i++)
+		if (freq <= (pdata->tuple_tab[i] & 0xFFFF))
+			return pdata->tuple_tab[i] >> 16;
+
+err_out:
+	printk(KERN_WARNING "DPMC: No suitable CCLK VDDINT voltage pair found\n");
+	return VLEV_120;
+}
+
+#ifdef CONFIG_CPU_FREQ
+static int
+vreg_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data)
+{
+	struct cpufreq_freqs *freq = data;
+
+	if (val == CPUFREQ_PRECHANGE && freq->old < freq->new) {
+		bfin_set_vlev(bfin_get_vlev(freq->new));
+		udelay(pdata->vr_settling_time); /* Wait until Volatge settled */
+
+	} else if (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)
+		bfin_set_vlev(bfin_get_vlev(freq->new));
+
+	return 0;
+}
+
+static struct notifier_block vreg_cpufreq_notifier_block = {
+	.notifier_call	= vreg_cpufreq_notifier
+};
+#endif /* CONFIG_CPU_FREQ */
+
+/**
+ *	bfin_dpmc_probe -
+ *
+ */
+static int __devinit bfin_dpmc_probe(struct platform_device *pdev)
+{
+	if (pdev->dev.platform_data)
+		pdata = pdev->dev.platform_data;
+	else
+		return -EINVAL;
+
+	return cpufreq_register_notifier(&vreg_cpufreq_notifier_block,
+					 CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+/**
+ *	bfin_dpmc_remove -
+ */
+static int __devexit bfin_dpmc_remove(struct platform_device *pdev)
+{
+	pdata = NULL;
+	return cpufreq_unregister_notifier(&vreg_cpufreq_notifier_block,
+					 CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+struct platform_driver bfin_dpmc_device_driver = {
+	.probe   = bfin_dpmc_probe,
+	.remove  = __devexit_p(bfin_dpmc_remove),
+	.driver  = {
+		.name = DRIVER_NAME,
+	}
+};
+
+/**
+ *	bfin_dpmc_init - Init driver
+ */
+static int __init bfin_dpmc_init(void)
+{
+	return platform_driver_register(&bfin_dpmc_device_driver);
+}
+module_init(bfin_dpmc_init);
+
+/**
+ *	bfin_dpmc_exit - break down driver
+ */
+static void __exit bfin_dpmc_exit(void)
+{
+	platform_driver_unregister(&bfin_dpmc_device_driver);
+}
+module_exit(bfin_dpmc_exit);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("cpu power management driver for Blackfin");
+MODULE_LICENSE("GPL");