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>

1 files changed, 96 insertions, 0 deletions

diff --git a/arch/arm/mach-msm/gpiomux.c b/arch/arm/mach-msm/gpiomux.c
new file mode 100644
index 000000000000..53af21abd155
--- /dev/null
+++ b/arch/arm/mach-msm/gpiomux.c
@@ -0,0 +1,96 @@
+/* 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.
+ */
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include "gpiomux.h"
+
+static DEFINE_SPINLOCK(gpiomux_lock);
+
+int msm_gpiomux_write(unsigned gpio,
+                      gpiomux_config_t active,
+                      gpiomux_config_t suspended)
+{
+        struct msm_gpiomux_config *cfg = msm_gpiomux_configs + gpio;
+        unsigned long irq_flags;
+        gpiomux_config_t setting;
+
+        if (gpio >= GPIOMUX_NGPIOS)
+                return -EINVAL;
+
+        spin_lock_irqsave(&gpiomux_lock, irq_flags);
+
+        if (active & GPIOMUX_VALID)
+                cfg->active = active;
+
+        if (suspended & GPIOMUX_VALID)
+                cfg->suspended = suspended;
+
+        setting = cfg->ref ? active : suspended;
+        if (setting & GPIOMUX_VALID)
+                __msm_gpiomux_write(gpio, setting);
+
+        spin_unlock_irqrestore(&gpiomux_lock, irq_flags);
+        return 0;
+}
+EXPORT_SYMBOL(msm_gpiomux_write);
+
+int msm_gpiomux_get(unsigned gpio)
+{
+        struct msm_gpiomux_config *cfg = msm_gpiomux_configs + gpio;
+        unsigned long irq_flags;
+
+        if (gpio >= GPIOMUX_NGPIOS)
+                return -EINVAL;
+
+        spin_lock_irqsave(&gpiomux_lock, irq_flags);
+        if (cfg->ref++ == 0 && cfg->active & GPIOMUX_VALID)
+                __msm_gpiomux_write(gpio, cfg->active);
+        spin_unlock_irqrestore(&gpiomux_lock, irq_flags);
+        return 0;
+}
+EXPORT_SYMBOL(msm_gpiomux_get);
+
+int msm_gpiomux_put(unsigned gpio)
+{
+        struct msm_gpiomux_config *cfg = msm_gpiomux_configs + gpio;
+        unsigned long irq_flags;
+
+        if (gpio >= GPIOMUX_NGPIOS)
+                return -EINVAL;
+
+        spin_lock_irqsave(&gpiomux_lock, irq_flags);
+        BUG_ON(cfg->ref == 0);
+        if (--cfg->ref == 0 && cfg->suspended & GPIOMUX_VALID)
+                __msm_gpiomux_write(gpio, cfg->suspended);
+        spin_unlock_irqrestore(&gpiomux_lock, irq_flags);
+        return 0;
+}
+EXPORT_SYMBOL(msm_gpiomux_put);
+
+static int __init gpiomux_init(void)
+{
+        unsigned n;
+
+        for (n = 0; n < GPIOMUX_NGPIOS; ++n) {
+                msm_gpiomux_configs[n].ref = 0;
+                if (!(msm_gpiomux_configs[n].suspended & GPIOMUX_VALID))
+                        continue;
+                __msm_gpiomux_write(n, msm_gpiomux_configs[n].suspended);
+        }
+        return 0;
+}
+postcore_initcall(gpiomux_init);