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ARM: davinci: gpio: use gpiolib API instead of inline functions

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Remove NEED_MACH_GPIO_H config select option for ARCH_DAVINCI
to start using gpiolib interface for davinci platforms. This makes
it easier to use the gpio driver on other platforms as it breaks
dependency on mach-davinci.

Latencies for gpio_get/set APIs will increase. On measurement,
latency was found to have increased by 18 microsecond with
gpiolib API as compared to inline APIs.

Measurement was done on DA850 EVM for gpio_get_value() API by
taking the printk timing across the call with interrupts disabled.

  inline gpio API with interrupt disabled
  [   29.734337] before gpio_get
  [   29.736847] after gpio_get

  Time difference 0.00251

  gpio library with interrupt disabled
  [  272.876763] before gpio_get
  [  272.879291] after gpio_get

  Time difference 0.002528
  Latency increased by (0.002528 -  0.00251) = 18 microsecond.

While at it, remove GPIO_TYPE_DAVINCI enum definition as
gpio-davinci.c is converted to Linux device driver model.

Signed-off-by: Philip Avinash <avinashphilip@ti.com>
Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
[nsekhar@ti.com: minor edits to commit message]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
This commit is contained in:
Philip Avinash 2013-08-18 10:49:03 +05:30 committed by Sekhar Nori
parent 834acb2af6
commit f1a4c52ff5
5 changed files with 36 additions and 179 deletions
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1
arch/arm/Kconfig
View File

@ -847,7 +847,6 @@ config ARCH_DAVINCI
select GENERIC_CLOCKEVENTS
select GENERIC_IRQ_CHIP
select HAVE_IDE
select NEED_MACH_GPIO_H
select TI_PRIV_EDMA
select USE_OF
select ZONE_DMA

90
arch/arm/mach-davinci/include/mach/gpio-davinci.h
View File

@ -1,90 +0,0 @@
/*
* TI DaVinci GPIO Support
*
* Copyright (c) 2006 David Brownell
* Copyright (c) 2007, MontaVista Software, Inc. <source@mvista.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#ifndef __DAVINCI_DAVINCI_GPIO_H
#define __DAVINCI_DAVINCI_GPIO_H
#include <linux/io.h>
#include <linux/spinlock.h>
#include <asm-generic/gpio.h>
#include <mach/irqs.h>
#include <mach/common.h>
enum davinci_gpio_type {
GPIO_TYPE_DAVINCI = 0,
GPIO_TYPE_TNETV107X,
};
/*
* basic gpio routines
*
* board-specific init should be done by arch/.../.../board-XXX.c (maybe
* initializing banks together) rather than boot loaders; kexec() won't
* go through boot loaders.
*
* the gpio clock will be turned on when gpios are used, and you may also
* need to pay attention to PINMUX registers to be sure those pins are
* used as gpios, not with other peripherals.
*
* On-chip GPIOs are numbered 0..(DAVINCI_N_GPIO-1). For documentation,
* and maybe for later updates, code may write GPIO(N). These may be
* all 1.8V signals, all 3.3V ones, or a mix of the two. A given chip
* may not support all the GPIOs in that range.
*
* GPIOs can also be on external chips, numbered after the ones built-in
* to the DaVinci chip. For now, they won't be usable as IRQ sources.
*/
#define GPIO(X) (X) /* 0 <= X <= (DAVINCI_N_GPIO - 1) */
/* Convert GPIO signal to GPIO pin number */
#define GPIO_TO_PIN(bank, gpio) (16 * (bank) + (gpio))
struct davinci_gpio_controller {
struct gpio_chip chip;
int irq_base;
spinlock_t lock;
void __iomem *regs;
void __iomem *set_data;
void __iomem *clr_data;
void __iomem *in_data;
unsigned gpio_irq;
};
/* The __gpio_to_controller() and __gpio_mask() functions inline to constants
* with constant parameters; or in outlined code they execute at runtime.
*
* You'd access the controller directly when reading or writing more than
* one gpio value at a time, and to support wired logic where the value
* being driven by the cpu need not match the value read back.
*
* These are NOT part of the cross-platform GPIO interface
*/
static inline struct davinci_gpio_controller *
__gpio_to_controller(unsigned gpio)
{
struct davinci_gpio_controller *ctlrs = davinci_soc_info.gpio_ctlrs;
int index = gpio / 32;
if (!ctlrs || index >= davinci_soc_info.gpio_ctlrs_num)
return NULL;
return ctlrs + index;
}
static inline u32 __gpio_mask(unsigned gpio)
{
return 1 << (gpio % 32);
}
#endif /* __DAVINCI_DAVINCI_GPIO_H */

88
arch/arm/mach-davinci/include/mach/gpio.h
View File

@ -1,88 +0,0 @@
/*
* TI DaVinci GPIO Support
*
* Copyright (c) 2006 David Brownell
* Copyright (c) 2007, MontaVista Software, Inc. <source@mvista.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#ifndef __DAVINCI_GPIO_H
#define __DAVINCI_GPIO_H
#include <asm-generic/gpio.h>
#define __ARM_GPIOLIB_COMPLEX
/* The inline versions use the static inlines in the driver header */
#include "gpio-davinci.h"
/*
* The get/set/clear functions will inline when called with constant
* parameters referencing built-in GPIOs, for low-overhead bitbanging.
*
* gpio_set_value() will inline only on traditional Davinci style controllers
* with distinct set/clear registers.
*
* Otherwise, calls with variable parameters or referencing external
* GPIOs (e.g. on GPIO expander chips) use outlined functions.
*/
static inline void gpio_set_value(unsigned gpio, int value)
{
if (__builtin_constant_p(value) && gpio < davinci_soc_info.gpio_num) {
struct davinci_gpio_controller *ctlr;
u32 mask;
ctlr = __gpio_to_controller(gpio);
if (ctlr->set_data != ctlr->clr_data) {
mask = __gpio_mask(gpio);
if (value)
__raw_writel(mask, ctlr->set_data);
else
__raw_writel(mask, ctlr->clr_data);
return;
}
}
__gpio_set_value(gpio, value);
}
/* Returns zero or nonzero; works for gpios configured as inputs OR
* as outputs, at least for built-in GPIOs.
*
* NOTE: for built-in GPIOs, changes in reported values are synchronized
* to the GPIO clock. This is easily seen after calling gpio_set_value()
* and then immediately gpio_get_value(), where the gpio_get_value() will
* return the old value until the GPIO clock ticks and the new value gets
* latched.
*/
static inline int gpio_get_value(unsigned gpio)
{
struct davinci_gpio_controller *ctlr;
if (!__builtin_constant_p(gpio) || gpio >= davinci_soc_info.gpio_num)
return __gpio_get_value(gpio);
ctlr = __gpio_to_controller(gpio);
return __gpio_mask(gpio) & __raw_readl(ctlr->in_data);
}
static inline int gpio_cansleep(unsigned gpio)
{
if (__builtin_constant_p(gpio) && gpio < davinci_soc_info.gpio_num)
return 0;
else
return __gpio_cansleep(gpio);
}
static inline int irq_to_gpio(unsigned irq)
{
/* don't support the reverse mapping */
return -ENOSYS;
}
#endif /* __DAVINCI_GPIO_H */

1
drivers/gpio/gpio-tnetv107x.c
View File

@ -15,6 +15,7 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio.h>
#include <linux/platform_data/gpio-davinci.h>
#include <mach/common.h>
#include <mach/tnetv107x.h>

35
include/linux/platform_data/gpio-davinci.h
View File

@ -16,10 +16,45 @@
#ifndef __DAVINCI_GPIO_PLATFORM_H
#define __DAVINCI_GPIO_PLATFORM_H
#include <linux/io.h>
#include <linux/spinlock.h>
#include <asm-generic/gpio.h>
enum davinci_gpio_type {
GPIO_TYPE_TNETV107X = 0,
};
struct davinci_gpio_platform_data {
u32 ngpio;
u32 gpio_unbanked;
u32 intc_irq_num;
};
struct davinci_gpio_controller {
struct gpio_chip chip;
int irq_base;
/* Serialize access to GPIO registers */
spinlock_t lock;
void __iomem *regs;
void __iomem *set_data;
void __iomem *clr_data;
void __iomem *in_data;
int gpio_unbanked;
unsigned gpio_irq;
};
/*
* basic gpio routines
*/
#define GPIO(X) (X) /* 0 <= X <= (DAVINCI_N_GPIO - 1) */
/* Convert GPIO signal to GPIO pin number */
#define GPIO_TO_PIN(bank, gpio) (16 * (bank) + (gpio))
static inline u32 __gpio_mask(unsigned gpio)
{
return 1 << (gpio % 32);
}
#endif