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authorGregory Bean <gbean@codeaurora.org>2010-08-28 10:05:44 -0700
committerDaniel Walker <dwalker@codeaurora.org>2010-10-06 09:01:15 -0700
commit1963a2afc81afe6d85e7a12538b74a9919d958ae (patch)
treef1486399cfce632819509cb86639d3106d539805 /arch/arm/mach-msm/gpiomux.h
parent846afbd1fe015e082c89d56dd42c484d896ef58e (diff)
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>
Diffstat (limited to 'arch/arm/mach-msm/gpiomux.h')
-rw-r--r--arch/arm/mach-msm/gpiomux.h94
1 files changed, 94 insertions, 0 deletions
diff --git a/arch/arm/mach-msm/gpiomux.h b/arch/arm/mach-msm/gpiomux.h
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+/* 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