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linux-next/arch/arm/mach-pxa/mfp-pxa2xx.c
Igor Grinberg ef7c7c693b ARM: PXA2xx: MFP: fix potential direction bug 
Pins configured as input and have MFP_LPM_DRIVE_* flag set, can have a
wrong output value for some period of time (spike) during the suspend
sequence.
This can happen because the direction of the pins (GPDR) is set by
software and the output level is set by hardware (PGSR) at a later
stage.

Fix the above potential bug by setting the output levels first.
Also save the actual levels of the pins before the suspend and restore
them after the resume, but before the direction settings take place, so
the same bug as described above will not happen in the resume sequence.

Reported-by: Paul Parsons <lost.distance@yahoo.com>
Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Tested-by: Paul Parsons <lost.distance@yahoo.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>
2012-04-27 11:14:06 +08:00

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/*
* linux/arch/arm/mach-pxa/mfp-pxa2xx.c
*
* PXA2xx pin mux configuration support
*
* The GPIOs on PXA2xx can be configured as one of many alternate
* functions, this is by concept samilar to the MFP configuration
* on PXA3xx, what's more important, the low power pin state and
* wakeup detection are also supported by the same framework.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/gpio.h>
#include <linux/gpio-pxa.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/syscore_ops.h>
#include <mach/pxa2xx-regs.h>
#include <mach/mfp-pxa2xx.h>
#include "generic.h"
#define PGSR(x) __REG2(0x40F00020, (x) << 2)
#define __GAFR(u, x) __REG2((u) ? 0x40E00058 : 0x40E00054, (x) << 3)
#define GAFR_L(x) __GAFR(0, x)
#define GAFR_U(x) __GAFR(1, x)
#define BANK_OFF(n) (((n) < 3) ? (n) << 2 : 0x100 + (((n) - 3) << 2))
#define GPLR(x) __REG2(0x40E00000, BANK_OFF((x) >> 5))
#define GPDR(x) __REG2(0x40E00000, BANK_OFF((x) >> 5) + 0x0c)
#define GPSR(x) __REG2(0x40E00000, BANK_OFF((x) >> 5) + 0x18)
#define GPCR(x) __REG2(0x40E00000, BANK_OFF((x) >> 5) + 0x24)
#define PWER_WE35 (1 << 24)
struct gpio_desc {
unsigned valid : 1;
unsigned can_wakeup : 1;
unsigned keypad_gpio : 1;
unsigned dir_inverted : 1;
unsigned int mask; /* bit mask in PWER or PKWR */
unsigned int mux_mask; /* bit mask of muxed gpio bits, 0 if no mux */
unsigned long config;
};
static struct gpio_desc gpio_desc[MFP_PIN_GPIO127 + 1];
static unsigned long gpdr_lpm[4];
static int __mfp_config_gpio(unsigned gpio, unsigned long c)
{
unsigned long gafr, mask = GPIO_bit(gpio);
int bank = gpio_to_bank(gpio);
int uorl = !!(gpio & 0x10); /* GAFRx_U or GAFRx_L ? */
int shft = (gpio & 0xf) << 1;
int fn = MFP_AF(c);
int is_out = (c & MFP_DIR_OUT) ? 1 : 0;
if (fn > 3)
return -EINVAL;
/* alternate function and direction at run-time */
gafr = (uorl == 0) ? GAFR_L(bank) : GAFR_U(bank);
gafr = (gafr & ~(0x3 << shft)) | (fn << shft);
if (uorl == 0)
GAFR_L(bank) = gafr;
else
GAFR_U(bank) = gafr;
if (is_out ^ gpio_desc[gpio].dir_inverted)
GPDR(gpio) |= mask;
else
GPDR(gpio) &= ~mask;
/* alternate function and direction at low power mode */
switch (c & MFP_LPM_STATE_MASK) {
case MFP_LPM_DRIVE_HIGH:
PGSR(bank) |= mask;
is_out = 1;
break;
case MFP_LPM_DRIVE_LOW:
PGSR(bank) &= ~mask;
is_out = 1;
break;
case MFP_LPM_INPUT:
case MFP_LPM_DEFAULT:
break;
default:
/* warning and fall through, treat as MFP_LPM_DEFAULT */
pr_warning("%s: GPIO%d: unsupported low power mode\n",
__func__, gpio);
break;
}
if (is_out ^ gpio_desc[gpio].dir_inverted)
gpdr_lpm[bank] |= mask;
else
gpdr_lpm[bank] &= ~mask;
/* give early warning if MFP_LPM_CAN_WAKEUP is set on the
* configurations of those pins not able to wakeup
*/
if ((c & MFP_LPM_CAN_WAKEUP) && !gpio_desc[gpio].can_wakeup) {
pr_warning("%s: GPIO%d unable to wakeup\n",
__func__, gpio);
return -EINVAL;
}
if ((c & MFP_LPM_CAN_WAKEUP) && is_out) {
pr_warning("%s: output GPIO%d unable to wakeup\n",
__func__, gpio);
return -EINVAL;
}
return 0;
}
static inline int __mfp_validate(int mfp)
{
int gpio = mfp_to_gpio(mfp);
if ((mfp > MFP_PIN_GPIO127) || !gpio_desc[gpio].valid) {
pr_warning("%s: GPIO%d is invalid pin\n", __func__, gpio);
return -1;
}
return gpio;
}
void pxa2xx_mfp_config(unsigned long *mfp_cfgs, int num)
{
unsigned long flags;
unsigned long *c;
int i, gpio;
for (i = 0, c = mfp_cfgs; i < num; i++, c++) {
gpio = __mfp_validate(MFP_PIN(*c));
if (gpio < 0)
continue;
local_irq_save(flags);
gpio_desc[gpio].config = *c;
__mfp_config_gpio(gpio, *c);
local_irq_restore(flags);
}
}
void pxa2xx_mfp_set_lpm(int mfp, unsigned long lpm)
{
unsigned long flags, c;
int gpio;
gpio = __mfp_validate(mfp);
if (gpio < 0)
return;
local_irq_save(flags);
c = gpio_desc[gpio].config;
c = (c & ~MFP_LPM_STATE_MASK) | lpm;
__mfp_config_gpio(gpio, c);
local_irq_restore(flags);
}
int gpio_set_wake(unsigned int gpio, unsigned int on)
{
struct gpio_desc *d;
unsigned long c, mux_taken;
if (gpio > mfp_to_gpio(MFP_PIN_GPIO127))
return -EINVAL;
d = &gpio_desc[gpio];
c = d->config;
if (!d->valid)
return -EINVAL;
/* Allow keypad GPIOs to wakeup system when
* configured as generic GPIOs.
*/
if (d->keypad_gpio && (MFP_AF(d->config) == 0) &&
(d->config & MFP_LPM_CAN_WAKEUP)) {
if (on)
PKWR |= d->mask;
else
PKWR &= ~d->mask;
return 0;
}
mux_taken = (PWER & d->mux_mask) & (~d->mask);
if (on && mux_taken)
return -EBUSY;
if (d->can_wakeup && (c & MFP_LPM_CAN_WAKEUP)) {
if (on) {
PWER = (PWER & ~d->mux_mask) | d->mask;
if (c & MFP_LPM_EDGE_RISE)
PRER |= d->mask;
else
PRER &= ~d->mask;
if (c & MFP_LPM_EDGE_FALL)
PFER |= d->mask;
else
PFER &= ~d->mask;
} else {
PWER &= ~d->mask;
PRER &= ~d->mask;
PFER &= ~d->mask;
}
}
return 0;
}
#ifdef CONFIG_PXA25x
static void __init pxa25x_mfp_init(void)
{
int i;
/* running before pxa_gpio_probe() */
#ifdef CONFIG_CPU_PXA26x
pxa_last_gpio = 89;
#else
pxa_last_gpio = 84;
#endif
for (i = 0; i <= pxa_last_gpio; i++)
gpio_desc[i].valid = 1;
for (i = 0; i <= 15; i++) {
gpio_desc[i].can_wakeup = 1;
gpio_desc[i].mask = GPIO_bit(i);
}
/* PXA26x has additional 4 GPIOs (86/87/88/89) which has the
* direction bit inverted in GPDR2. See PXA26x DM 4.1.1.
*/
for (i = 86; i <= pxa_last_gpio; i++)
gpio_desc[i].dir_inverted = 1;
}
#else
static inline void pxa25x_mfp_init(void) {}
#endif /* CONFIG_PXA25x */
#ifdef CONFIG_PXA27x
static int pxa27x_pkwr_gpio[] = {
13, 16, 17, 34, 36, 37, 38, 39, 90, 91, 93, 94,
95, 96, 97, 98, 99, 100, 101, 102
};
int keypad_set_wake(unsigned int on)
{
unsigned int i, gpio, mask = 0;
struct gpio_desc *d;
for (i = 0; i < ARRAY_SIZE(pxa27x_pkwr_gpio); i++) {
gpio = pxa27x_pkwr_gpio[i];
d = &gpio_desc[gpio];
/* skip if configured as generic GPIO */
if (MFP_AF(d->config) == 0)
continue;
if (d->config & MFP_LPM_CAN_WAKEUP)
mask |= gpio_desc[gpio].mask;
}
if (on)
PKWR |= mask;
else
PKWR &= ~mask;
return 0;
}
#define PWER_WEMUX2_GPIO38 (1 << 16)
#define PWER_WEMUX2_GPIO53 (2 << 16)
#define PWER_WEMUX2_GPIO40 (3 << 16)
#define PWER_WEMUX2_GPIO36 (4 << 16)
#define PWER_WEMUX2_MASK (7 << 16)
#define PWER_WEMUX3_GPIO31 (1 << 19)
#define PWER_WEMUX3_GPIO113 (2 << 19)
#define PWER_WEMUX3_MASK (3 << 19)
#define INIT_GPIO_DESC_MUXED(mux, gpio) \
do { \
gpio_desc[(gpio)].can_wakeup = 1; \
gpio_desc[(gpio)].mask = PWER_ ## mux ## _GPIO ##gpio; \
gpio_desc[(gpio)].mux_mask = PWER_ ## mux ## _MASK; \
} while (0)
static void __init pxa27x_mfp_init(void)
{
int i, gpio;
pxa_last_gpio = 120; /* running before pxa_gpio_probe() */
for (i = 0; i <= pxa_last_gpio; i++) {
/* skip GPIO2, 5, 6, 7, 8, they are not
* valid pins allow configuration
*/
if (i == 2 || i == 5 || i == 6 || i == 7 || i == 8)
continue;
gpio_desc[i].valid = 1;
}
/* Keypad GPIOs */
for (i = 0; i < ARRAY_SIZE(pxa27x_pkwr_gpio); i++) {
gpio = pxa27x_pkwr_gpio[i];
gpio_desc[gpio].can_wakeup = 1;
gpio_desc[gpio].keypad_gpio = 1;
gpio_desc[gpio].mask = 1 << i;
}
/* Overwrite GPIO13 as a PWER wakeup source */
for (i = 0; i <= 15; i++) {
/* skip GPIO2, 5, 6, 7, 8 */
if (GPIO_bit(i) & 0x1e4)
continue;
gpio_desc[i].can_wakeup = 1;
gpio_desc[i].mask = GPIO_bit(i);
}
gpio_desc[35].can_wakeup = 1;
gpio_desc[35].mask = PWER_WE35;
INIT_GPIO_DESC_MUXED(WEMUX3, 31);
INIT_GPIO_DESC_MUXED(WEMUX3, 113);
INIT_GPIO_DESC_MUXED(WEMUX2, 38);
INIT_GPIO_DESC_MUXED(WEMUX2, 53);
INIT_GPIO_DESC_MUXED(WEMUX2, 40);
INIT_GPIO_DESC_MUXED(WEMUX2, 36);
}
#else
static inline void pxa27x_mfp_init(void) {}
#endif /* CONFIG_PXA27x */
#ifdef CONFIG_PM
static unsigned long saved_gafr[2][4];
static unsigned long saved_gpdr[4];
static unsigned long saved_gplr[4];
static unsigned long saved_pgsr[4];
static int pxa2xx_mfp_suspend(void)
{
int i;
/* set corresponding PGSR bit of those marked MFP_LPM_KEEP_OUTPUT */
for (i = 0; i < pxa_last_gpio; i++) {
if ((gpio_desc[i].config & MFP_LPM_KEEP_OUTPUT) &&
(GPDR(i) & GPIO_bit(i))) {
if (GPLR(i) & GPIO_bit(i))
PGSR(gpio_to_bank(i)) |= GPIO_bit(i);
else
PGSR(gpio_to_bank(i)) &= ~GPIO_bit(i);
}
}
for (i = 0; i <= gpio_to_bank(pxa_last_gpio); i++) {
saved_gafr[0][i] = GAFR_L(i);
saved_gafr[1][i] = GAFR_U(i);
saved_gpdr[i] = GPDR(i * 32);
saved_gplr[i] = GPLR(i * 32);
saved_pgsr[i] = PGSR(i);
GPSR(i * 32) = PGSR(i);
GPCR(i * 32) = ~PGSR(i);
}
/* set GPDR bits taking into account MFP_LPM_KEEP_OUTPUT */
for (i = 0; i < pxa_last_gpio; i++) {
if ((gpdr_lpm[gpio_to_bank(i)] & GPIO_bit(i)) ||
((gpio_desc[i].config & MFP_LPM_KEEP_OUTPUT) &&
(saved_gpdr[gpio_to_bank(i)] & GPIO_bit(i))))
GPDR(i) |= GPIO_bit(i);
else
GPDR(i) &= ~GPIO_bit(i);
}
return 0;
}
static void pxa2xx_mfp_resume(void)
{
int i;
for (i = 0; i <= gpio_to_bank(pxa_last_gpio); i++) {
GAFR_L(i) = saved_gafr[0][i];
GAFR_U(i) = saved_gafr[1][i];
GPSR(i * 32) = saved_gplr[i];
GPCR(i * 32) = ~saved_gplr[i];
GPDR(i * 32) = saved_gpdr[i];
PGSR(i) = saved_pgsr[i];
}
PSSR = PSSR_RDH | PSSR_PH;
}
#else
#define pxa2xx_mfp_suspend NULL
#define pxa2xx_mfp_resume NULL
#endif
struct syscore_ops pxa2xx_mfp_syscore_ops = {
.suspend = pxa2xx_mfp_suspend,
.resume = pxa2xx_mfp_resume,
};
static int __init pxa2xx_mfp_init(void)
{
int i;
if (!cpu_is_pxa2xx())
return 0;
if (cpu_is_pxa25x())
pxa25x_mfp_init();
if (cpu_is_pxa27x())
pxa27x_mfp_init();
/* clear RDH bit to enable GPIO receivers after reset/sleep exit */
PSSR = PSSR_RDH;
/* initialize gafr_run[], pgsr_lpm[] from existing values */
for (i = 0; i <= gpio_to_bank(pxa_last_gpio); i++)
gpdr_lpm[i] = GPDR(i * 32);
return 0;
}
postcore_initcall(pxa2xx_mfp_init);
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