IMX: introduce clock API

This patch introduces the clock API for i.MX and converts all
in-Kernel drivers to use it.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/mach-imx/clock.c

@@ -0,0 +1,205 @@
+/*
+ *  Copyright (C) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/math64.h>
+#include <linux/err.h>
+
+#include <asm/io.h>
+#include <asm/arch/imx-regs.h>
+
+/*
+ * Very simple approach: We can't disable clocks, so we do
+ * not need refcounting
+ */
+
+struct clk {
+	struct list_head node;
+	const char *name;
+	unsigned long (*get_rate)(void);
+};
+
+/*
+ *  get the system pll clock in Hz
+ *
+ *                  mfi + mfn / (mfd +1)
+ *  f = 2 * f_ref * --------------------
+ *                        pd + 1
+ */
+static unsigned long imx_decode_pll(unsigned int pll, u32 f_ref)
+{
+	unsigned long long ll;
+	unsigned long quot;
+
+	u32 mfi = (pll >> 10) & 0xf;
+	u32 mfn = pll & 0x3ff;
+	u32 mfd = (pll >> 16) & 0x3ff;
+	u32 pd =  (pll >> 26) & 0xf;
+
+	mfi = mfi <= 5 ? 5 : mfi;
+
+	ll = 2 * (unsigned long long)f_ref *
+		((mfi << 16) + (mfn << 16) / (mfd + 1));
+	quot = (pd + 1) * (1 << 16);
+	ll += quot / 2;
+	do_div(ll, quot);
+	return (unsigned long)ll;
+}
+
+static unsigned long imx_get_system_clk(void)
+{
+	u32 f_ref = (CSCR & CSCR_SYSTEM_SEL) ? 16000000 : (CLK32 * 512);
+
+	return imx_decode_pll(SPCTL0, f_ref);
+}
+
+static unsigned long imx_get_mcu_clk(void)
+{
+	return imx_decode_pll(MPCTL0, CLK32 * 512);
+}
+
+/*
+ *  get peripheral clock 1 ( UART[12], Timer[12], PWM )
+ */
+static unsigned long imx_get_perclk1(void)
+{
+	return imx_get_system_clk() / (((PCDR) & 0xf)+1);
+}
+
+/*
+ *  get peripheral clock 2 ( LCD, SD, SPI[12] )
+ */
+static unsigned long imx_get_perclk2(void)
+{
+	return imx_get_system_clk() / (((PCDR>>4) & 0xf)+1);
+}
+
+/*
+ *  get peripheral clock 3 ( SSI )
+ */
+static unsigned long imx_get_perclk3(void)
+{
+	return imx_get_system_clk() / (((PCDR>>16) & 0x7f)+1);
+}
+
+/*
+ *  get hclk ( SDRAM, CSI, Memory Stick, I2C, DMA )
+ */
+static unsigned long imx_get_hclk(void)
+{
+	return imx_get_system_clk() / (((CSCR>>10) & 0xf)+1);
+}
+
+static struct clk clk_system_clk = {
+	.name = "system_clk",
+	.get_rate = imx_get_system_clk,
+};
+
+static struct clk clk_hclk = {
+	.name = "hclk",
+	.get_rate = imx_get_hclk,
+};
+
+static struct clk clk_mcu_clk = {
+	.name = "mcu_clk",
+	.get_rate = imx_get_mcu_clk,
+};
+
+static struct clk clk_perclk1 = {
+	.name = "perclk1",
+	.get_rate = imx_get_perclk1,
+};
+
+static struct clk clk_uart_clk = {
+	.name = "uart_clk",
+	.get_rate = imx_get_perclk1,
+};
+
+static struct clk clk_perclk2 = {
+	.name = "perclk2",
+	.get_rate = imx_get_perclk2,
+};
+
+static struct clk clk_perclk3 = {
+	.name = "perclk3",
+	.get_rate = imx_get_perclk3,
+};
+
+static struct clk *clks[] = {
+	&clk_perclk1,
+	&clk_perclk2,
+	&clk_perclk3,
+	&clk_system_clk,
+	&clk_hclk,
+	&clk_mcu_clk,
+	&clk_uart_clk,
+};
+
+static LIST_HEAD(clocks);
+static DEFINE_MUTEX(clocks_mutex);
+
+struct clk *clk_get(struct device *dev, const char *id)
+{
+	struct clk *p, *clk = ERR_PTR(-ENOENT);
+
+	mutex_lock(&clocks_mutex);
+	list_for_each_entry(p, &clocks, node) {
+		if (!strcmp(p->name, id)) {
+			clk = p;
+			goto found;
+		}
+	}
+
+found:
+	mutex_unlock(&clocks_mutex);
+
+	return clk;
+}
+
+void clk_put(struct clk *clk)
+{
+}
+
+int clk_enable(struct clk *clk)
+{
+	return 0;
+}
+
+void clk_disable(struct clk *clk)
+{
+}
+
+unsigned long clk_get_rate(struct clk *clk)
+{
+	return clk->get_rate();
+}
+
+int imx_clocks_init(void)
+{
+	int i;
+
+	mutex_lock(&clocks_mutex);
+	for (i = 0; i < ARRAY_SIZE(clks); i++)
+		list_add(&clks[i]->node, &clocks);
+	mutex_unlock(&clocks_mutex);
+
+	return 0;
+}
+