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authorMike Turquette <mturquette@linaro.org>2012-03-15 23:11:20 -0700
committerArnd Bergmann <arnd@arndb.de>2012-03-16 20:35:02 +0000
commit9d9f78ed9af0e465d2fd15550471956e7f559b9f (patch)
tree8a65fc0844a35c928162f65b671a8a5786ea03ee /drivers/clk/clk-fixed-rate.c
parentb2476490ef11134b65544d8f062cff96c53e941b (diff)
downloadvexpress-lsk-9d9f78ed9af0e465d2fd15550471956e7f559b9f.tar.gz
clk: basic clock hardware types
Many platforms support simple gateable clocks, fixed-rate clocks, adjustable divider clocks and multi-parent multiplexer clocks. This patch introduces basic clock types for the above-mentioned hardware which share some common characteristics. Based on original work by Jeremy Kerr and contribution by Jamie Iles. Dividers and multiplexor clocks originally contributed by Richard Zhao & Sascha Hauer. Signed-off-by: Mike Turquette <mturquette@linaro.org> Signed-off-by: Mike Turquette <mturquette@ti.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Tested-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Rob Herring <rob.herring@calxeda.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergman <arnd.bergmann@linaro.org> Cc: Paul Walmsley <paul@pwsan.com> Cc: Shawn Guo <shawn.guo@freescale.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Jamie Iles <jamie@jamieiles.com> Cc: Richard Zhao <richard.zhao@linaro.org> Cc: Saravana Kannan <skannan@codeaurora.org> Cc: Magnus Damm <magnus.damm@gmail.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Linus Walleij <linus.walleij@stericsson.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Amit Kucheria <amit.kucheria@linaro.org> Cc: Deepak Saxena <dsaxena@linaro.org> Cc: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'drivers/clk/clk-fixed-rate.c')
-rw-r--r--drivers/clk/clk-fixed-rate.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/drivers/clk/clk-fixed-rate.c b/drivers/clk/clk-fixed-rate.c
new file mode 100644
index 00000000000..90c79fb5d1b
--- /dev/null
+++ b/drivers/clk/clk-fixed-rate.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * 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.
+ *
+ * Fixed rate clock implementation
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+
+/*
+ * DOC: basic fixed-rate clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_(un)prepare only ensures parents are prepared
+ * enable - clk_enable only ensures parents are enabled
+ * rate - rate is always a fixed value. No clk_set_rate support
+ * parent - fixed parent. No clk_set_parent support
+ */
+
+#define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)
+
+static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ return to_clk_fixed_rate(hw)->fixed_rate;
+}
+EXPORT_SYMBOL_GPL(clk_fixed_rate_recalc_rate);
+
+struct clk_ops clk_fixed_rate_ops = {
+ .recalc_rate = clk_fixed_rate_recalc_rate,
+};
+EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
+
+struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
+ const char *parent_name, unsigned long flags,
+ unsigned long fixed_rate)
+{
+ struct clk_fixed_rate *fixed;
+ char **parent_names = NULL;
+ u8 len;
+
+ fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL);
+
+ if (!fixed) {
+ pr_err("%s: could not allocate fixed clk\n", __func__);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /* struct clk_fixed_rate assignments */
+ fixed->fixed_rate = fixed_rate;
+
+ if (parent_name) {
+ parent_names = kmalloc(sizeof(char *), GFP_KERNEL);
+
+ if (! parent_names)
+ goto out;
+
+ len = sizeof(char) * strlen(parent_name);
+
+ parent_names[0] = kmalloc(len, GFP_KERNEL);
+
+ if (!parent_names[0])
+ goto out;
+
+ strncpy(parent_names[0], parent_name, len);
+ }
+
+out:
+ return clk_register(dev, name,
+ &clk_fixed_rate_ops, &fixed->hw,
+ parent_names,
+ (parent_name ? 1 : 0),
+ flags);
+}