msm: add gpiomux api for gpio multiplex & configuration.

Add the 'gpiomux' api, which addresses the following shortcomings
of existing tlmm api:

- gpio power-collapse, which is managed by a peripheral processor on
  other targets, must be managed by the application processor on the 8x60.
- The enable/disable flag of the legacy gpio_tlmm_config api
  is not applicable on the 8x60, and causes confusion.
- The gpio 'direction' bits are meaningless for all func_sel
  configurations except for generic-gpio mode (func_sel 0), in which
  case the gpio_direction_* functions should be used.  Having these
  bits in the tlmm api leads to confusion and misuse of the gpiolib
  api, and they have been removed in gpiomux.
- The functional api of the legacy system ran contrary to the typical
  use-case, which is a single massive configuration at boot.  Rather
  than forcing hundreds of 'config' function calls, the new api
  allows data to be configured with a single table.

gpiomux_get and gpiomux_put are meant to be called automatically
when gpio_request and gpio_free are called, giving automatic
gpiomux/tlmm control to those drivers/lines with simple
power profiles - in the simplest cases, an entry in the gpiomux table
and the correct usage of gpiolib is all that is required to get proper
gpio power control.

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>

arch/arm/mach-msm/gpiomux.h

@@ -0,0 +1,94 @@
+/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+#ifndef __ARCH_ARM_MACH_MSM_GPIOMUX_H
+#define __ARCH_ARM_MACH_MSM_GPIOMUX_H
+
+#include <linux/bitops.h>
+
+#if defined(CONFIG_MSM_V2_TLMM)
+#include "gpiomux-v2.h"
+#else
+#include "gpiomux-v1.h"
+#endif
+
+/**
+ * struct msm_gpiomux_config: gpiomux settings for one gpio line.
+ *
+ * A complete gpiomux config is the bitwise-or of a drive-strength,
+ * function, and pull.  For functions other than GPIO, the OE
+ * is hard-wired according to the function.  For GPIO mode,
+ * OE is controlled by gpiolib.
+ *
+ * Available settings differ by target; see the gpiomux header
+ * specific to your target arch for available configurations.
+ *
+ * @active: The configuration to be installed when the line is
+ * active, or its reference count is > 0.
+ * @suspended: The configuration to be installed when the line
+ * is suspended, or its reference count is 0.
+ * @ref: The reference count of the line.  For internal use of
+ * the gpiomux framework only.
+ */
+struct msm_gpiomux_config {
+	gpiomux_config_t active;
+	gpiomux_config_t suspended;
+	unsigned         ref;
+};
+
+/**
+ * @GPIOMUX_VALID:	If set, the config field contains 'good data'.
+ *                      The absence of this bit will prevent the gpiomux
+ *			system from applying the configuration under all
+ *			circumstances.
+ */
+enum {
+	GPIOMUX_VALID	 = BIT(sizeof(gpiomux_config_t) * BITS_PER_BYTE - 1),
+	GPIOMUX_CTL_MASK = GPIOMUX_VALID,
+};
+
+/* Each architecture must provide its own instance of this table.
+ * To avoid having gpiomux manage any given gpio, one or both of
+ * the entries can avoid setting GPIOMUX_VALID - the absence
+ * of that flag will prevent the configuration from being applied
+ * during state transitions.
+ */
+extern struct msm_gpiomux_config msm_gpiomux_configs[GPIOMUX_NGPIOS];
+
+/* Increment a gpio's reference count, possibly activating the line. */
+int __must_check msm_gpiomux_get(unsigned gpio);
+
+/* Decrement a gpio's reference count, possibly suspending the line. */
+int msm_gpiomux_put(unsigned gpio);
+
+/* Install a new configuration to the gpio line.  To avoid overwriting
+ * a configuration, leave the VALID bit out.
+ */
+int msm_gpiomux_write(unsigned gpio,
+		      gpiomux_config_t active,
+		      gpiomux_config_t suspended);
+
+/* Architecture-internal function for use by the framework only.
+ * This function can assume the following:
+ * - the gpio value has passed a bounds-check
+ * - the gpiomux spinlock has been obtained
+ *
+ * This function is not for public consumption.  External users
+ * should use msm_gpiomux_write.
+ */
+void __msm_gpiomux_write(unsigned gpio, gpiomux_config_t val);
+
+#endif