TI Davinci: add a pin multiplexer configuration API

Creates a method allowing pin settings to be logically grouped into data
structure arrays and provides an API to configure the pinmux settings to
enable the relevant pin functions.

Signed-off-by: Nick Thompson <nick.thompson@gefanuc.com>

board/davinci/common/misc.c

@@ -1,6 +1,7 @@
 /*
  * Miscelaneous DaVinci functions.
  *
+ * Copyright (C) 2009 Nick Thompson, GE Fanuc Ltd, <nick.thompson@gefanuc.com>
  * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
  * Copyright (C) 2008 Lyrtech <www.lyrtech.com>
  * Copyright (C) 2004 Texas Instruments.
@@ -27,7 +28,8 @@
 #include <i2c.h>
 #include <net.h>
 #include <asm/arch/hardware.h>
-
+#include <asm/io.h>
+#include "misc.h"
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -109,3 +111,47 @@ void dv_configure_mac_address(uint8_t *rom_enetaddr)
 }
 
 #endif	/* DAVINCI_EMAC */
+
+/*
+ * Change the setting of a pin multiplexer field.
+ *
+ * Takes an array of pinmux settings similar to:
+ *
+ * struct pinmux_config uart_pins[] = {
+ *	{ &davinci_syscfg_regs->pinmux[8], 2, 7 },
+ *	{ &davinci_syscfg_regs->pinmux[9], 2, 0 }
+ * };
+ *
+ * Stepping through the array, each pinmux[n] register has the given value
+ * set in the pin mux field specified.
+ *
+ * The number of pins in the array must be passed (ARRAY_SIZE can provide
+ * this value conveniently).
+ *
+ * Returns 0 if all field numbers and values are in the correct range,
+ * else returns -1.
+ */
+int davinci_configure_pin_mux(const struct pinmux_config *pins,
+			      const int n_pins)
+{
+	int i;
+
+	/* check for invalid pinmux values */
+	for (i = 0; i < n_pins; i++) {
+		if (pins[i].field >= PIN_MUX_NUM_FIELDS ||
+		    (pins[i].value & ~PIN_MUX_FIELD_MASK) != 0)
+			return -1;
+	}
+
+	/* configure the pinmuxes */
+	for (i = 0; i < n_pins; i++) {
+		const int offset = pins[i].field * PIN_MUX_FIELD_SIZE;
+		const unsigned int value = pins[i].value << offset;
+		const unsigned int mask = PIN_MUX_FIELD_MASK << offset;
+		const dv_reg *mux = pins[i].mux;
+
+		writel(value | (readl(mux) & (~mask)), mux);
+	}
+
+	return 0;
+}

board/davinci/common/misc.h

@@ -22,8 +22,20 @@
 #ifndef __MISC_H
 #define __MISC_H
 
+/* pin muxer definitions */
+#define PIN_MUX_NUM_FIELDS	8	/* Per register */
+#define PIN_MUX_FIELD_SIZE	4	/* n in bits */
+#define PIN_MUX_FIELD_MASK	((1 << PIN_MUX_FIELD_SIZE) - 1)
+
+/* pin definition */
+struct pinmux_config {
+	dv_reg		*mux;		/* Address of mux register */
+	unsigned char	value;		/* Value to set in field */
+	unsigned char	field;		/* field number */
+};
 
 int dvevm_read_mac_address(uint8_t *buf);
 void dv_configure_mac_address(uint8_t *rom_enetaddr);
+int davinci_configure_pin_mux(const struct pinmux_config *pins, int n_pins);
 
 #endif /* __MISC_H */