summaryrefslogtreecommitdiff
path: root/drivers/clk/mvebu
diff options
context:
space:
mode:
authorMike Turquette <mturquette@linaro.org>2014-08-28 04:11:38 +0400
committerMike Turquette <mturquette@linaro.org>2014-09-02 04:43:52 +0400
commite8e8a9b0d86c093b208789fd71501c91a919ffdb (patch)
treee443d76dee27e562bc7b94b5d52eb49493798cb8 /drivers/clk/mvebu
parent87e392164ab6c0f3f055f8483dc7dc3f1afa19ad (diff)
downloadlinux-e8e8a9b0d86c093b208789fd71501c91a919ffdb.tar.xz
clk: mvebu: powersave clock is a multiplexer
Kirkwood is unique among the mvebu SoCs for having a clock multiplexer that feeds into the cpu. This multiplexer can select either the cpu pll or the ddr clock as its input signal, allowing for a choice between performance and power savings. This patch introduces the code needed to register the clock multiplexer on Kirkwood SoCs but does not include the clock data to actually register the clock. That will be done in a follow-up patch which is necessary to prevent breaking git bisect. Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Mike Turquette <mturquette@linaro.org>
Diffstat (limited to 'drivers/clk/mvebu')
-rw-r--r--drivers/clk/mvebu/kirkwood.c87
1 files changed, 87 insertions, 0 deletions
diff --git a/drivers/clk/mvebu/kirkwood.c b/drivers/clk/mvebu/kirkwood.c
index ddb666a86500..f73a2fa8a561 100644
--- a/drivers/clk/mvebu/kirkwood.c
+++ b/drivers/clk/mvebu/kirkwood.c
@@ -13,9 +13,11 @@
*/
#include <linux/kernel.h>
+#include <linux/slab.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/of.h>
+#include <linux/of_address.h>
#include "common.h"
/*
@@ -225,6 +227,91 @@ static const struct clk_gating_soc_desc kirkwood_gating_desc[] __initconst = {
{ }
};
+
+/*
+ * Clock Muxing Control
+ */
+
+struct clk_muxing_soc_desc {
+ const char *name;
+ const char **parents;
+ int num_parents;
+ int shift;
+ int width;
+ unsigned long flags;
+};
+
+struct clk_muxing_ctrl {
+ spinlock_t *lock;
+ struct clk **muxes;
+ int num_muxes;
+};
+
+#define to_clk_mux(_hw) container_of(_hw, struct clk_mux, hw)
+
+static struct clk *clk_muxing_get_src(
+ struct of_phandle_args *clkspec, void *data)
+{
+ struct clk_muxing_ctrl *ctrl = (struct clk_muxing_ctrl *)data;
+ int n;
+
+ if (clkspec->args_count < 1)
+ return ERR_PTR(-EINVAL);
+
+ for (n = 0; n < ctrl->num_muxes; n++) {
+ struct clk_mux *mux =
+ to_clk_mux(__clk_get_hw(ctrl->muxes[n]));
+ if (clkspec->args[0] == mux->shift)
+ return ctrl->muxes[n];
+ }
+ return ERR_PTR(-ENODEV);
+}
+
+static void __init kirkwood_clk_muxing_setup(struct device_node *np,
+ const struct clk_muxing_soc_desc *desc)
+{
+ struct clk_muxing_ctrl *ctrl;
+ void __iomem *base;
+ int n;
+
+ base = of_iomap(np, 0);
+ if (WARN_ON(!base))
+ return;
+
+ ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
+ if (WARN_ON(!ctrl))
+ goto ctrl_out;
+
+ /* lock must already be initialized */
+ ctrl->lock = &ctrl_gating_lock;
+
+ /* Count, allocate, and register clock muxes */
+ for (n = 0; desc[n].name;)
+ n++;
+
+ ctrl->num_muxes = n;
+ ctrl->muxes = kcalloc(ctrl->num_muxes, sizeof(struct clk *),
+ GFP_KERNEL);
+ if (WARN_ON(!ctrl->muxes))
+ goto muxes_out;
+
+ for (n = 0; n < ctrl->num_muxes; n++) {
+ ctrl->muxes[n] = clk_register_mux(NULL, desc[n].name,
+ desc[n].parents, desc[n].num_parents,
+ desc[n].flags, base, desc[n].shift,
+ desc[n].width, desc[n].flags, ctrl->lock);
+ WARN_ON(IS_ERR(ctrl->muxes[n]));
+ }
+
+ of_clk_add_provider(np, clk_muxing_get_src, ctrl);
+
+ return;
+muxes_out:
+ kfree(ctrl);
+ctrl_out:
+ iounmap(base);
+}
+
static void __init kirkwood_clk_init(struct device_node *np)
{
struct device_node *cgnp =