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>

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 000000000000..90c79fb5d1bd
--- /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);
+}