OMAP2xxx clock: move the APLL clock code into mach-omap2/clkt2xxx_apll.c

Move the APLL-related clock functions from clock2xxx.c to
mach-omap2/clkt2xxx_apll.c.  This is intended to make the clock code
easier to understand, since all of the functions needed to manage APLLs
are now located in their own file, rather than being mixed with other,
unrelated functions.

Clock debugging is also now more finely-grained, since the DEBUG
macro can now be defined for APLL clocks alone.  This
should reduce unnecessary console noise when debugging.

Also, if at some future point the mach-omap2/ directory is split
into OMAP2/3/4 variants, this clkt file can be placed in the mach-omap2xxx/
directory, rather than shared with other chip types that don't use this
clock type.

Thanks to Alexander Shishkin <virtuoso@slind.org> for his comments to
improve the patch description.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Richard Woodruff <r-woodruff2@ti.com>
Cc: Alexander Shishkin <virtuoso@slind.org>

1 files changed, 120 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/clkt2xxx_apll.c b/arch/arm/mach-omap2/clkt2xxx_apll.c
new file mode 100644
index 0000000..fc32ff8
--- /dev/null
+++ b/arch/arm/mach-omap2/clkt2xxx_apll.c
@@ -0,0 +1,120 @@
+/*
+ * OMAP2xxx APLL clock control functions
+ *
+ * Copyright (C) 2005-2008 Texas Instruments, Inc.
+ * Copyright (C) 2004-2010 Nokia Corporation
+ *
+ * Contacts:
+ * Richard Woodruff <r-woodruff2@ti.com>
+ * Paul Walmsley
+ *
+ * Based on earlier work by Tuukka Tikkanen, Tony Lindgren,
+ * Gordon McNutt and RidgeRun, Inc.
+ *
+ * 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.
+ */
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#include <plat/clock.h>
+#include <plat/prcm.h>
+
+#include "clock.h"
+#include "clock2xxx.h"
+#include "cm.h"
+#include "cm-regbits-24xx.h"
+
+/* CM_CLKEN_PLL.EN_{54,96}M_PLL options (24XX) */
+#define EN_APLL_STOPPED			0
+#define EN_APLL_LOCKED			3
+
+/* CM_CLKSEL1_PLL.APLLS_CLKIN options (24XX) */
+#define APLLS_CLKIN_19_2MHZ		0
+#define APLLS_CLKIN_13MHZ		2
+#define APLLS_CLKIN_12MHZ		3
+
+/* Private functions */
+
+/* Enable an APLL if off */
+static int omap2_clk_apll_enable(struct clk *clk, u32 status_mask)
+{
+	u32 cval, apll_mask;
+
+	apll_mask = EN_APLL_LOCKED << clk->enable_bit;
+
+	cval = cm_read_mod_reg(PLL_MOD, CM_CLKEN);
+
+	if ((cval & apll_mask) == apll_mask)
+		return 0;   /* apll already enabled */
+
+	cval &= ~apll_mask;
+	cval |= apll_mask;
+	cm_write_mod_reg(cval, PLL_MOD, CM_CLKEN);
+
+	omap2_cm_wait_idlest(OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST), status_mask,
+			     clk->name);
+
+	/*
+	 * REVISIT: Should we return an error code if omap2_wait_clock_ready()
+	 * fails?
+	 */
+	return 0;
+}
+
+static int omap2_clk_apll96_enable(struct clk *clk)
+{
+	return omap2_clk_apll_enable(clk, OMAP24XX_ST_96M_APLL);
+}
+
+static int omap2_clk_apll54_enable(struct clk *clk)
+{
+	return omap2_clk_apll_enable(clk, OMAP24XX_ST_54M_APLL);
+}
+
+/* Stop APLL */
+static void omap2_clk_apll_disable(struct clk *clk)
+{
+	u32 cval;
+
+	cval = cm_read_mod_reg(PLL_MOD, CM_CLKEN);
+	cval &= ~(EN_APLL_LOCKED << clk->enable_bit);
+	cm_write_mod_reg(cval, PLL_MOD, CM_CLKEN);
+}
+
+/* Public data */
+
+const struct clkops clkops_apll96 = {
+	.enable		= omap2_clk_apll96_enable,
+	.disable	= omap2_clk_apll_disable,
+};
+
+const struct clkops clkops_apll54 = {
+	.enable		= omap2_clk_apll54_enable,
+	.disable	= omap2_clk_apll_disable,
+};
+
+/* Public functions */
+
+u32 omap2xxx_get_apll_clkin(void)
+{
+	u32 aplls, srate = 0;
+
+	aplls = cm_read_mod_reg(PLL_MOD, CM_CLKSEL1);
+	aplls &= OMAP24XX_APLLS_CLKIN_MASK;
+	aplls >>= OMAP24XX_APLLS_CLKIN_SHIFT;
+
+	if (aplls == APLLS_CLKIN_19_2MHZ)
+		srate = 19200000;
+	else if (aplls == APLLS_CLKIN_13MHZ)
+		srate = 13000000;
+	else if (aplls == APLLS_CLKIN_12MHZ)
+		srate = 12000000;
+
+	return srate;
+}
+