mx31: rework of iomux support

This new implemenatation avoids that two physical pins are claimed by
the same driver (also with the the gpr hardware modes).
The gpio kernel lib is also called when a capable gpio pin is assigned
its gpio function.
The mxc_iomux_mode function is still here for backward compatibility but
should not be used anymore.

V2:

In the precendent revision, the iomux code was claiming a pin when its
hardware mode was changed. This was uncorrect: when the hardware mode is
changed, the pin must still be claimed through the iomux.

In order to have a pin working in mode hw2, we must fist issue the
mxc_iomux_set_gpr call and then the corresponding mxc_iomux_mode calls
with the FUNC mode (usually done with mxc_iomux_setup_multiple_pins).
The reverse calls must be done to fee the pins.

Signed-off-by: Valentin Longchamp <valentin.longchamp@epfl.ch>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/mach-mx3/iomux.c

@@ -1,6 +1,7 @@
 /*
  * Copyright 2004-2006 Freescale Semiconductor, Inc. All Rights Reserved.
  * Copyright (C) 2008 by Sascha Hauer <kernel@pengutronix.de>
+ * Copyright (C) 2009 by Valentin Longchamp <valentin.longchamp@epfl.ch>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -21,6 +22,7 @@
 #include <linux/spinlock.h>
 #include <linux/io.h>
 #include <linux/gpio.h>
+#include <linux/kernel.h>
 #include <mach/hardware.h>
 #include <mach/gpio.h>
 #include <mach/iomux-mx3.h>
@@ -38,6 +40,8 @@
 static DEFINE_SPINLOCK(gpio_mux_lock);
 
 #define IOMUX_REG_MASK (IOMUX_PADNUM_MASK & ~0x3)
+
+unsigned long mxc_pin_alloc_map[NB_PORTS * 32 / BITS_PER_LONG];
 /*
  * set the mode for a IOMUX pin.
  */
@@ -50,9 +54,6 @@ int mxc_iomux_mode(unsigned int pin_mode)
 	field = pin_mode & 0x3;
 	mode = (pin_mode & IOMUX_MODE_MASK) >> IOMUX_MODE_SHIFT;
 
-	pr_debug("%s: reg offset = 0x%x field = %d mode = 0x%02x\n",
-			__func__, (pin_mode & IOMUX_REG_MASK), field, mode);
-
 	spin_lock(&gpio_mux_lock);
 
 	l = __raw_readl(reg);
@@ -92,6 +93,86 @@ void mxc_iomux_set_pad(enum iomux_pins pin, u32 config)
 }
 EXPORT_SYMBOL(mxc_iomux_set_pad);
 
+/*
+ * setups a single pin:
+ * 	- reserves the pin so that it is not claimed by another driver
+ * 	- setups the iomux according to the configuration
+ * 	- if the pin is configured as a GPIO, we claim it through kernel gpiolib
+ */
+int mxc_iomux_setup_pin(const unsigned int pin, const char *label)
+{
+	unsigned pad = pin & IOMUX_PADNUM_MASK;
+	unsigned gpio;
+
+	if (pad >= (PIN_MAX + 1)) {
+		printk(KERN_ERR "mxc_iomux: Attempt to request nonexistant pin %u for \"%s\"\n",
+			pad, label ? label : "?");
+		return -EINVAL;
+	}
+
+	if (test_and_set_bit(pad, mxc_pin_alloc_map)) {
+		printk(KERN_ERR "mxc_iomux: pin %u already used. Allocation for \"%s\" failed\n",
+			pad, label ? label : "?");
+		return -EINVAL;
+	}
+	mxc_iomux_mode(pin);
+
+	/* if we have a gpio, we can allocate it */
+	gpio = (pin & IOMUX_GPIONUM_MASK) >> IOMUX_GPIONUM_SHIFT;
+	if (gpio < (GPIO_PORT_MAX + 1) * 32)
+		if (gpio_request(gpio, label))
+			return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL(mxc_iomux_setup_pin);
+
+int mxc_iomux_setup_multiple_pins(unsigned int *pin_list, unsigned count,
+		const char *label)
+{
+	unsigned int *p = pin_list;
+	int i;
+	int ret = -EINVAL;
+
+	for (i = 0; i < count; i++) {
+		if (mxc_iomux_setup_pin(*p, label))
+			goto setup_error;
+		p++;
+	}
+	return 0;
+
+setup_error:
+	mxc_iomux_release_multiple_pins(pin_list, i);
+	return ret;
+}
+EXPORT_SYMBOL(mxc_iomux_setup_multiple_pins);
+
+void mxc_iomux_release_pin(const unsigned int pin)
+{
+	unsigned pad = pin & IOMUX_PADNUM_MASK;
+	unsigned gpio;
+
+	if (pad < (PIN_MAX + 1))
+		clear_bit(pad, mxc_pin_alloc_map);
+
+	gpio = (pin & IOMUX_GPIONUM_MASK) >> IOMUX_GPIONUM_SHIFT;
+	if (gpio < (GPIO_PORT_MAX + 1) * 32)
+		gpio_free(gpio);
+}
+EXPORT_SYMBOL(mxc_iomux_release_pin);
+
+void mxc_iomux_release_multiple_pins(unsigned int *pin_list, int count)
+{
+	unsigned int *p = pin_list;
+	int i;
+
+	for (i = 0; i < count; i++) {
+		mxc_iomux_release_pin(*p);
+		p++;
+	}
+}
+EXPORT_SYMBOL(mxc_iomux_release_multiple_pins);
+
 /*
  * This function enables/disables the general purpose function for a particular
  * signal.
@@ -111,4 +192,3 @@ void mxc_iomux_set_gpr(enum iomux_gp_func gp, bool en)
 	spin_unlock(&gpio_mux_lock);
 }
 EXPORT_SYMBOL(mxc_iomux_set_gpr);
-

arch/arm/plat-mxc/include/mach/iomux-mx3.h

@@ -92,7 +92,7 @@ enum iomux_gp_func {
 	MUX_EXTDMAREQ2_MBX_SEL		= 1 << 15,
 	MUX_TAMPER_DETECT_EN		= 1 << 16,
 	MUX_PGP_USB_4WIRE		= 1 << 17,
-	MUX_PGB_USB_COMMON		= 1 << 18,
+	MUX_PGP_USB_COMMON		= 1 << 18,
 	MUX_SDHC_MEMSTICK1		= 1 << 19,
 	MUX_SDHC_MEMSTICK2		= 1 << 20,
 	MUX_PGP_SPLL_BYP		= 1 << 21,
@@ -109,21 +109,44 @@ enum iomux_gp_func {
 };
 
 /*
- * This function enables/disables the general purpose function for a particular
- * signal.
+ * setups a single pin:
+ * 	- reserves the pin so that it is not claimed by another driver
+ * 	- setups the iomux according to the configuration
+ * 	- if the pin is configured as a GPIO, we claim it throug kernel gpiolib
+ */
+int mxc_iomux_setup_pin(const unsigned int pin, const char *label);
+/*
+ * setups mutliple pins
+ * convenient way to call the above function with tables
  */
-void iomux_config_gpr(enum iomux_gp_func , bool);
+int mxc_iomux_setup_multiple_pins(unsigned int *pin_list, unsigned count,
+		const char *label);
 
 /*
- * set the mode for a IOMUX pin.
+ * releases a single pin:
+ * 	- make it available for a future use by another driver
+ * 	- frees the GPIO if the pin was configured as GPIO
+ * 	- DOES NOT reconfigure the IOMUX in its reset state
  */
-int mxc_iomux_mode(unsigned int);
+void mxc_iomux_release_pin(const unsigned int pin);
+/*
+ * releases multiple pins
+ * convenvient way to call the above function with tables
+ */
+void mxc_iomux_release_multiple_pins(unsigned int *pin_list, int count);
 
 /*
  * This function enables/disables the general purpose function for a particular
  * signal.
  */
-void mxc_iomux_set_gpr(enum iomux_gp_func, bool);
+void mxc_iomux_set_gpr(enum iomux_gp_func, bool en);
+
+/*
+ * This function only configures the iomux hardware.
+ * It is called by the setup functions and should not be called directly anymore.
+ * It is here visible for backward compatibility
+ */
+int mxc_iomux_mode(unsigned int pin_mode);
 
 #define IOMUX_PADNUM_MASK	0x1ff
 #define IOMUX_GPIONUM_SHIFT	9
@@ -143,6 +166,11 @@ void mxc_iomux_set_gpr(enum iomux_gp_func, bool);
 	(((iomux_pin & IOMUX_GPIONUM_MASK) >> IOMUX_GPIONUM_SHIFT) + \
 	MXC_GPIO_IRQ_START)
 
+/*
+ * The number of gpio devices among the pads
+ */
+#define GPIO_PORT_MAX 3
+
 /*
  * This enumeration is constructed based on the Section
  * "sw_pad_ctl & sw_mux_ctl details" of the MX31 IC Spec. Each enumerated
@@ -480,6 +508,9 @@ enum iomux_pins {
 	MX31_PIN_CAPTURE	= IOMUX_PIN( 7,   327),
 };
 
+#define PIN_MAX 327
+#define NB_PORTS 12 /* NB_PINS/32, we chose 32 pins per "PORT" */
+
 /*
  * Convenience values for use with mxc_iomux_mode()
  *