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authorChen-Yu Tsai <wens@csie.org>2014-09-16 14:04:01 +0400
committerMaxime Ripard <maxime.ripard@free-electrons.com>2014-09-27 11:05:43 +0400
commit9c8176bfb67f98ed9a521b624dcb6ab7fa254aa7 (patch)
tree52bf5988af67aa1c7423010c09dbccfe9ab40671 /drivers/clk/sunxi/clk-sun8i-mbus.c
parent37e1041f04717d726931c8688cbf425071aeb9c1 (diff)
downloadlinux-9c8176bfb67f98ed9a521b624dcb6ab7fa254aa7.tar.xz
clk: sunxi: Add sun8i MBUS clock support
The MBUS clock on sun8i is slightly different from the old mod0 clocks. The divider is 3 bits wider, while also needing a divider table for the higher 4 values, which all set the same divider. Signed-off-by: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Diffstat (limited to 'drivers/clk/sunxi/clk-sun8i-mbus.c')
-rw-r--r--drivers/clk/sunxi/clk-sun8i-mbus.c78
1 files changed, 78 insertions, 0 deletions
diff --git a/drivers/clk/sunxi/clk-sun8i-mbus.c b/drivers/clk/sunxi/clk-sun8i-mbus.c
new file mode 100644
index 000000000000..8e49b44cee41
--- /dev/null
+++ b/drivers/clk/sunxi/clk-sun8i-mbus.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2014 Chen-Yu Tsai
+ *
+ * Chen-Yu Tsai <wens@csie.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; 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/clkdev.h>
+#include <linux/of_address.h>
+
+#include "clk-factors.h"
+
+/**
+ * sun8i_a23_get_mbus_factors() - calculates m factor for MBUS clocks
+ * MBUS rate is calculated as follows
+ * rate = parent_rate / (m + 1);
+ */
+
+static void sun8i_a23_get_mbus_factors(u32 *freq, u32 parent_rate,
+ u8 *n, u8 *k, u8 *m, u8 *p)
+{
+ u8 div;
+
+ /*
+ * These clocks can only divide, so we will never be able to
+ * achieve frequencies higher than the parent frequency
+ */
+ if (*freq > parent_rate)
+ *freq = parent_rate;
+
+ div = DIV_ROUND_UP(parent_rate, *freq);
+
+ if (div > 8)
+ div = 8;
+
+ *freq = parent_rate / div;
+
+ /* we were called to round the frequency, we can now return */
+ if (m == NULL)
+ return;
+
+ *m = div - 1;
+}
+
+static struct clk_factors_config sun8i_a23_mbus_config = {
+ .mshift = 0,
+ .mwidth = 3,
+};
+
+static const struct factors_data sun8i_a23_mbus_data __initconst = {
+ .enable = 31,
+ .mux = 24,
+ .table = &sun8i_a23_mbus_config,
+ .getter = sun8i_a23_get_mbus_factors,
+};
+
+static DEFINE_SPINLOCK(sun8i_a23_mbus_lock);
+
+static void __init sun8i_a23_mbus_setup(struct device_node *node)
+{
+ struct clk *mbus = sunxi_factors_register(node, &sun8i_a23_mbus_data,
+ &sun8i_a23_mbus_lock);
+
+ /* The MBUS clocks needs to be always enabled */
+ __clk_get(mbus);
+ clk_prepare_enable(mbus);
+}
+CLK_OF_DECLARE(sun8i_a23_mbus, "allwinner,sun8i-a23-mbus-clk", sun8i_a23_mbus_setup);