diff options
author | Gregory Bean <gbean@codeaurora.org> | 2010-08-28 17:05:44 (GMT) |
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committer | Daniel Walker <dwalker@codeaurora.org> | 2010-10-06 16:01:15 (GMT) |
commit | 1963a2afc81afe6d85e7a12538b74a9919d958ae (patch) | |
tree | f1486399cfce632819509cb86639d3106d539805 /arch/arm/mach-msm/gpiomux.h | |
parent | 846afbd1fe015e082c89d56dd42c484d896ef58e (diff) | |
download | linux-1963a2afc81afe6d85e7a12538b74a9919d958ae.tar.xz |
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.h | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/arch/arm/mach-msm/gpiomux.h b/arch/arm/mach-msm/gpiomux.h new file mode 100644 index 0000000..bb0acf0 --- /dev/null +++ b/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 |