ARM: imx: add common clock support for pfd

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

1 files changed, 147 insertions, 0 deletions

diff --git a/arch/arm/mach-imx/clk-pfd.c b/arch/arm/mach-imx/clk-pfd.c
new file mode 100644
index 000000000000..e2ed4160f329
--- /dev/null
+++ b/arch/arm/mach-imx/clk-pfd.c
@@ -0,0 +1,147 @@
+/*
+ * Copyright 2012 Freescale Semiconductor, Inc.
+ * Copyright 2012 Linaro Ltd.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include "clk.h"
+
+/**
+ * struct clk_pfd - IMX PFD clock
+ * @clk_hw:	clock source
+ * @reg:	PFD register address
+ * @idx:	the index of PFD encoded in the register
+ *
+ * PFD clock found on i.MX6 series.  Each register for PFD has 4 clk_pfd
+ * data encoded, and member idx is used to specify the one.  And each
+ * register has SET, CLR and TOG registers at offset 0x4 0x8 and 0xc.
+ */
+struct clk_pfd {
+	struct clk_hw	hw;
+	void __iomem	*reg;
+	u8		idx;
+};
+
+#define to_clk_pfd(_hw) container_of(_hw, struct clk_pfd, hw)
+
+#define SET	0x4
+#define CLR	0x8
+#define OTG	0xc
+
+static int clk_pfd_enable(struct clk_hw *hw)
+{
+	struct clk_pfd *pfd = to_clk_pfd(hw);
+
+	writel_relaxed(1 << ((pfd->idx + 1) * 8 - 1), pfd->reg + CLR);
+
+	return 0;
+}
+
+static void clk_pfd_disable(struct clk_hw *hw)
+{
+	struct clk_pfd *pfd = to_clk_pfd(hw);
+
+	writel_relaxed(1 << ((pfd->idx + 1) * 8 - 1), pfd->reg + SET);
+}
+
+static unsigned long clk_pfd_recalc_rate(struct clk_hw *hw,
+					 unsigned long parent_rate)
+{
+	struct clk_pfd *pfd = to_clk_pfd(hw);
+	u64 tmp = parent_rate;
+	u8 frac = (readl_relaxed(pfd->reg) >> (pfd->idx * 8)) & 0x3f;
+
+	tmp *= 18;
+	do_div(tmp, frac);
+
+	return tmp;
+}
+
+static long clk_pfd_round_rate(struct clk_hw *hw, unsigned long rate,
+			       unsigned long *prate)
+{
+	u64 tmp = *prate;
+	u8 frac;
+
+	tmp = tmp * 18 + rate / 2;
+	do_div(tmp, rate);
+	frac = tmp;
+	if (frac < 12)
+		frac = 12;
+	else if (frac > 35)
+		frac = 35;
+	tmp = *prate;
+	tmp *= 18;
+	do_div(tmp, frac);
+
+	return tmp;
+}
+
+static int clk_pfd_set_rate(struct clk_hw *hw, unsigned long rate,
+		unsigned long parent_rate)
+{
+	struct clk_pfd *pfd = to_clk_pfd(hw);
+	u64 tmp = parent_rate;
+	u8 frac;
+
+	tmp = tmp * 18 + rate / 2;
+	do_div(tmp, rate);
+	frac = tmp;
+	if (frac < 12)
+		frac = 12;
+	else if (frac > 35)
+		frac = 35;
+
+	writel_relaxed(0x3f << (pfd->idx * 8), pfd->reg + CLR);
+	writel_relaxed(frac << (pfd->idx * 8), pfd->reg + SET);
+
+	return 0;
+}
+
+static const struct clk_ops clk_pfd_ops = {
+	.enable		= clk_pfd_enable,
+	.disable	= clk_pfd_disable,
+	.recalc_rate	= clk_pfd_recalc_rate,
+	.round_rate	= clk_pfd_round_rate,
+	.set_rate	= clk_pfd_set_rate,
+};
+
+struct clk *imx_clk_pfd(const char *name, const char *parent_name,
+			void __iomem *reg, u8 idx)
+{
+	struct clk_pfd *pfd;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	pfd = kzalloc(sizeof(*pfd), GFP_KERNEL);
+	if (!pfd)
+		return ERR_PTR(-ENOMEM);
+
+	pfd->reg = reg;
+	pfd->idx = idx;
+
+	init.name = name;
+	init.ops = &clk_pfd_ops;
+	init.flags = 0;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	pfd->hw.init = &init;
+
+	clk = clk_register(NULL, &pfd->hw);
+	if (IS_ERR(clk))
+		kfree(pfd);
+
+	return clk;
+}