ARM: tegra: clock: Add debugfs clock set methods

Implemented debugfs clock write mechanism (disabled by default).
Expanded and fixed debugfs clock nodes to properly read clock
parent and rate.

Original-Change-Id: I9f20994d0829634e09f4bccd6fce6c7c8b5bf844
Reviewed-on: http://git-master/r/15315
Tested-by: Amit Kamath <akamath@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

Rebase-Id: Ra802d13d77e74c6e8def92a93c08157f8eb888fe

2 files changed, 96 insertions, 2 deletions

diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig
index d20ab5b559ff..87b0f8a69fe3 100644
--- a/arch/arm/mach-tegra/Kconfig
+++ b/arch/arm/mach-tegra/Kconfig
@@ -163,4 +163,9 @@ config WIFI_CONTROL_FUNC
 	help
 	  Enables Power/Reset/Carddetect function abstraction
 
+config TEGRA_CLOCK_DEBUG_WRITE
+	bool "Enable debugfs write access to clock tree"
+	depends on DEBUG_FS
+	default n
+
 endif
diff --git a/arch/arm/mach-tegra/clock.c b/arch/arm/mach-tegra/clock.c
index 1f68b97a584c..889c032767f4 100644
--- a/arch/arm/mach-tegra/clock.c
+++ b/arch/arm/mach-tegra/clock.c
@@ -26,6 +26,7 @@
 #include <linux/module.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 
 #include <mach/clk.h>
 
@@ -773,6 +774,88 @@ static const struct file_operations possible_parents_fops = {
 	.release	= single_release,
 };
 
+static int parent_show(struct seq_file *s, void *data)
+{
+	struct clk *c = s->private;
+	struct clk *p = clk_get_parent(c);
+
+	seq_printf(s, "%s\n", p ? p->name : "clk_root");
+	return 0;
+}
+
+static int parent_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, parent_show, inode->i_private);
+}
+
+static int rate_get(void *data, u64 *val)
+{
+	struct clk *c = (struct clk *)data;
+	*val = (u64)clk_get_rate(c);
+	return 0;
+}
+
+#ifdef CONFIG_TEGRA_CLOCK_DEBUG_WRITE
+
+static const mode_t parent_rate_mode =  S_IRUGO | S_IWUGO;
+
+static ssize_t parent_write(struct file *file,
+	const char __user *userbuf, size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct clk *c = s->private;
+	struct clk *p = NULL;
+	char buf[32];
+
+	if (sizeof(buf) <= count)
+		return -EINVAL;
+
+	if (copy_from_user(buf, userbuf, count))
+		return -EFAULT;
+
+	/* terminate buffer and trim - white spaces may be appended
+	 *  at the end when invoked from shell command line */
+	buf[count]='\0';
+	strim(buf);
+
+	p = tegra_get_clock_by_name(buf);
+	if (!p)
+		return -EINVAL;
+
+	clk_set_parent(c, p);
+	return count;
+}
+
+static const struct file_operations parent_fops = {
+	.open		= parent_open,
+	.read		= seq_read,
+	.write		= parent_write,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int rate_set(void *data, u64 val)
+{
+	struct clk *c = (struct clk *)data;
+	clk_set_rate(c, (unsigned long)val);
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(rate_fops, rate_get, rate_set, "%llu\n");
+
+#else
+
+static const mode_t parent_rate_mode =  S_IRUGO;
+
+static const struct file_operations parent_fops = {
+	.open		= parent_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+DEFINE_SIMPLE_ATTRIBUTE(rate_fops, rate_get, NULL, "%llu\n");
+#endif
+
 static int clk_debugfs_register_one(struct clk *c)
 {
 	struct dentry *d;
@@ -786,11 +869,17 @@ static int clk_debugfs_register_one(struct clk *c)
 	if (!d)
 		goto err_out;
 
-	d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
+	d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 	if (!d)
 		goto err_out;
 
-	d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
+	d = debugfs_create_file(
+		"parent", parent_rate_mode, c->dent, c, &parent_fops);
+	if (!d)
+		goto err_out;
+
+	d = debugfs_create_file(
+		"rate", parent_rate_mode, c->dent, c, &rate_fops);
 	if (!d)
 		goto err_out;