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>

5 files changed, 188 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/clock/ti/autoidle.txt b/Documentation/devicetree/bindings/clock/ti/autoidle.txt
new file mode 100644
index 000000000000..7c735dde9fe9
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/ti/autoidle.txt
@@ -0,0 +1,39 @@
+Binding for Texas Instruments autoidle clock.
+
+Binding status: Unstable - ABI compatibility may be broken in the future
+
+This binding uses the common clock binding[1]. It assumes a register mapped
+clock which can be put to idle automatically by hardware based on the usage
+and a configuration bit setting. Autoidle clock is never an individual
+clock, it is always a derivative of some basic clock like a gate, divider,
+or fixed-factor.
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- reg : offset for the register controlling the autoidle
+- ti,autoidle-shift : bit shift of the autoidle enable bit
+- ti,invert-autoidle-bit : autoidle is enabled by setting the bit to 0
+
+Examples:
+        dpll_core_m4_ck: dpll_core_m4_ck {
+                #clock-cells = <0>;
+                compatible = "ti,divider-clock";
+                clocks = <&dpll_core_x2_ck>;
+                ti,max-div = <31>;
+                ti,autoidle-shift = <8>;
+                reg = <0x2d38>;
+                ti,index-starts-at-one;
+                ti,invert-autoidle-bit;
+        };
+
+        dpll_usb_clkdcoldo_ck: dpll_usb_clkdcoldo_ck {
+                #clock-cells = <0>;
+                compatible = "ti,fixed-factor-clock";
+                clocks = <&dpll_usb_ck>;
+                ti,clock-div = <1>;
+                ti,autoidle-shift = <8>;
+                reg = <0x01b4>;
+                ti,clock-mult = <1>;
+                ti,invert-autoidle-bit;
+        };
diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
index c7c5d31e9082..238be3f1ddce 100644
--- a/arch/arm/mach-omap2/clock.c
+++ b/arch/arm/mach-omap2/clock.c
@@ -520,6 +520,9 @@ int omap2_clk_enable_autoidle_all(void)
         list_for_each_entry(c, &clk_hw_omap_clocks, node)
                 if (c->ops && c->ops->allow_idle)
                         c->ops->allow_idle(c);
+
+        of_ti_clk_allow_autoidle_all();
+
         return 0;
 }
 
@@ -539,6 +542,9 @@ int omap2_clk_disable_autoidle_all(void)
         list_for_each_entry(c, &clk_hw_omap_clocks, node)
                 if (c->ops && c->ops->deny_idle)
                         c->ops->deny_idle(c);
+
+        of_ti_clk_deny_autoidle_all();
+
         return 0;
 }
 
diff --git a/drivers/clk/ti/Makefile b/drivers/clk/ti/Makefile
index 3dbb78dc9fca..7fa1a48df4f3 100644
--- a/drivers/clk/ti/Makefile
+++ b/drivers/clk/ti/Makefile
@@ -1,4 +1,4 @@
 ifneq ($(CONFIG_OF),)
-obj-y                                   += clk.o
+obj-y                                   += clk.o autoidle.o
 clk-common                              = dpll.o
 endif
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;
+}
diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
index 3f9de3973582..ca38ee3620b1 100644
--- a/include/linux/clk/ti.h
+++ b/include/linux/clk/ti.h
@@ -242,6 +242,15 @@ void ti_dt_clocks_register(struct ti_dt_clk *oclks);
 void ti_dt_clk_init_provider(struct device_node *np, int index);
 int ti_clk_retry_init(struct device_node *node, struct clk_hw *hw,
                       ti_of_clk_init_cb_t func);
+int of_ti_clk_autoidle_setup(struct device_node *node);
+
+#ifdef CONFIG_OF
+void of_ti_clk_allow_autoidle_all(void);
+void of_ti_clk_deny_autoidle_all(void);
+#else
+static inline void of_ti_clk_allow_autoidle_all(void) { }
+static inline void of_ti_clk_deny_autoidle_all(void) { }
+#endif
 
 extern const struct clk_hw_omap_ops clkhwops_omap3_dpll;
 extern const struct clk_hw_omap_ops clkhwops_omap4_dpllmx;