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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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1963a2afc8
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>
97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include "gpiomux.h"
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static DEFINE_SPINLOCK(gpiomux_lock);
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int msm_gpiomux_write(unsigned gpio,
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gpiomux_config_t active,
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gpiomux_config_t suspended)
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{
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struct msm_gpiomux_config *cfg = msm_gpiomux_configs + gpio;
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unsigned long irq_flags;
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gpiomux_config_t setting;
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if (gpio >= GPIOMUX_NGPIOS)
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return -EINVAL;
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spin_lock_irqsave(&gpiomux_lock, irq_flags);
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if (active & GPIOMUX_VALID)
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cfg->active = active;
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if (suspended & GPIOMUX_VALID)
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cfg->suspended = suspended;
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setting = cfg->ref ? active : suspended;
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if (setting & GPIOMUX_VALID)
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__msm_gpiomux_write(gpio, setting);
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spin_unlock_irqrestore(&gpiomux_lock, irq_flags);
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return 0;
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}
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EXPORT_SYMBOL(msm_gpiomux_write);
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int msm_gpiomux_get(unsigned gpio)
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{
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struct msm_gpiomux_config *cfg = msm_gpiomux_configs + gpio;
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unsigned long irq_flags;
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if (gpio >= GPIOMUX_NGPIOS)
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return -EINVAL;
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spin_lock_irqsave(&gpiomux_lock, irq_flags);
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if (cfg->ref++ == 0 && cfg->active & GPIOMUX_VALID)
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__msm_gpiomux_write(gpio, cfg->active);
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spin_unlock_irqrestore(&gpiomux_lock, irq_flags);
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return 0;
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}
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EXPORT_SYMBOL(msm_gpiomux_get);
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int msm_gpiomux_put(unsigned gpio)
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{
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struct msm_gpiomux_config *cfg = msm_gpiomux_configs + gpio;
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unsigned long irq_flags;
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if (gpio >= GPIOMUX_NGPIOS)
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return -EINVAL;
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spin_lock_irqsave(&gpiomux_lock, irq_flags);
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BUG_ON(cfg->ref == 0);
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if (--cfg->ref == 0 && cfg->suspended & GPIOMUX_VALID)
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__msm_gpiomux_write(gpio, cfg->suspended);
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spin_unlock_irqrestore(&gpiomux_lock, irq_flags);
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return 0;
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}
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EXPORT_SYMBOL(msm_gpiomux_put);
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static int __init gpiomux_init(void)
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{
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unsigned n;
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for (n = 0; n < GPIOMUX_NGPIOS; ++n) {
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msm_gpiomux_configs[n].ref = 0;
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if (!(msm_gpiomux_configs[n].suspended & GPIOMUX_VALID))
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continue;
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__msm_gpiomux_write(n, msm_gpiomux_configs[n].suspended);
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}
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return 0;
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}
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postcore_initcall(gpiomux_init);
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