CLK: TI: add autoidle support

TI clk driver now routes some of the basic clocks through own
registration routine to allow autoidle support. This routine just
checks a couple of device node properties and adds autoidle support
if required, and just passes the registration forward to basic clocks.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

1 files changed, 133 insertions, 0 deletions

diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
new file mode 100644
index 000000000000..8912ff80af34
--- /dev/null
+++ b/drivers/clk/ti/autoidle.c
@@ -0,0 +1,133 @@
+/*
+ * TI clock autoidle support
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ *
+ * Tero Kristo <t-kristo@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clk/ti.h>
+
+struct clk_ti_autoidle {
+	void __iomem		*reg;
+	u8			shift;
+	u8			flags;
+	const char		*name;
+	struct list_head	node;
+};
+
+#define AUTOIDLE_LOW		0x1
+
+static LIST_HEAD(autoidle_clks);
+
+static void ti_allow_autoidle(struct clk_ti_autoidle *clk)
+{
+	u32 val;
+
+	val = ti_clk_ll_ops->clk_readl(clk->reg);
+
+	if (clk->flags & AUTOIDLE_LOW)
+		val &= ~(1 << clk->shift);
+	else
+		val |= (1 << clk->shift);
+
+	ti_clk_ll_ops->clk_writel(val, clk->reg);
+}
+
+static void ti_deny_autoidle(struct clk_ti_autoidle *clk)
+{
+	u32 val;
+
+	val = ti_clk_ll_ops->clk_readl(clk->reg);
+
+	if (clk->flags & AUTOIDLE_LOW)
+		val |= (1 << clk->shift);
+	else
+		val &= ~(1 << clk->shift);
+
+	ti_clk_ll_ops->clk_writel(val, clk->reg);
+}
+
+/**
+ * of_ti_clk_allow_autoidle_all - enable autoidle for all clocks
+ *
+ * Enables hardware autoidle for all registered DT clocks, which have
+ * the feature.
+ */
+void of_ti_clk_allow_autoidle_all(void)
+{
+	struct clk_ti_autoidle *c;
+
+	list_for_each_entry(c, &autoidle_clks, node)
+		ti_allow_autoidle(c);
+}
+
+/**
+ * of_ti_clk_deny_autoidle_all - disable autoidle for all clocks
+ *
+ * Disables hardware autoidle for all registered DT clocks, which have
+ * the feature.
+ */
+void of_ti_clk_deny_autoidle_all(void)
+{
+	struct clk_ti_autoidle *c;
+
+	list_for_each_entry(c, &autoidle_clks, node)
+		ti_deny_autoidle(c);
+}
+
+/**
+ * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock
+ * @node: pointer to the clock device node
+ *
+ * Checks if a clock has hardware autoidle support or not (check
+ * for presence of 'ti,autoidle-shift' property in the device tree
+ * node) and sets up the hardware autoidle feature for the clock
+ * if available. If autoidle is available, the clock is also added
+ * to the autoidle list for later processing. Returns 0 on success,
+ * negative error value on failure.
+ */
+int __init of_ti_clk_autoidle_setup(struct device_node *node)
+{
+	u32 shift;
+	struct clk_ti_autoidle *clk;
+
+	/* Check if this clock has autoidle support or not */
+	if (of_property_read_u32(node, "ti,autoidle-shift", &shift))
+		return 0;
+
+	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+
+	if (!clk)
+		return -ENOMEM;
+
+	clk->shift = shift;
+	clk->name = node->name;
+	clk->reg = ti_clk_get_reg_addr(node, 0);
+
+	if (!clk->reg) {
+		kfree(clk);
+		return -EINVAL;
+	}
+
+	if (of_property_read_bool(node, "ti,invert-autoidle-bit"))
+		clk->flags |= AUTOIDLE_LOW;
+
+	list_add(&clk->node, &autoidle_clks);
+
+	return 0;
+}