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linux/drivers/gpio/gpio-wm831x.c
Linus Walleij 51c27da19d gpio: wm831x: use the new open drain callback 
The WM831x GPIOs clearly have a dedicated open drain control
register. Implement support for controlling this from GPIO
descriptor tables or other hardware descriptions such as
device tree by implementing the .set_single_ended() callback.

Before this patch, lines requesting open drain will just be
switched to input mode by the framework, thus emulating open
drain. But the hardware can do the real thing, so let's
support that.

As part of this, rename the debugfs string for output mode
from "CMOS" to "push-pull" because it is the term used in
the framework to signify a tomem-pole CMOS output.

Cc: patches@opensource.wolfsonmicro.com
Cc: Mark Brown <broonie@kernel.org>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-04-14 14:03:28 +02:00

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/*
* gpiolib support for Wolfson WM831x PMICs
*
* Copyright 2009 Wolfson Microelectronics PLC.
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.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.
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/mfd/core.h>
#include <linux/platform_device.h>
#include <linux/seq_file.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/gpio.h>
#include <linux/mfd/wm831x/irq.h>
struct wm831x_gpio {
struct wm831x *wm831x;
struct gpio_chip gpio_chip;
};
static int wm831x_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
{
struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
struct wm831x *wm831x = wm831x_gpio->wm831x;
int val = WM831X_GPN_DIR;
if (wm831x->has_gpio_ena)
val |= WM831X_GPN_TRI;
return wm831x_set_bits(wm831x, WM831X_GPIO1_CONTROL + offset,
WM831X_GPN_DIR | WM831X_GPN_TRI |
WM831X_GPN_FN_MASK, val);
}
static int wm831x_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
struct wm831x *wm831x = wm831x_gpio->wm831x;
int ret;
ret = wm831x_reg_read(wm831x, WM831X_GPIO_LEVEL);
if (ret < 0)
return ret;
if (ret & 1 << offset)
return 1;
else
return 0;
}
static void wm831x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
struct wm831x *wm831x = wm831x_gpio->wm831x;
wm831x_set_bits(wm831x, WM831X_GPIO_LEVEL, 1 << offset,
value << offset);
}
static int wm831x_gpio_direction_out(struct gpio_chip *chip,
unsigned offset, int value)
{
struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
struct wm831x *wm831x = wm831x_gpio->wm831x;
int val = 0;
int ret;
if (wm831x->has_gpio_ena)
val |= WM831X_GPN_TRI;
ret = wm831x_set_bits(wm831x, WM831X_GPIO1_CONTROL + offset,
WM831X_GPN_DIR | WM831X_GPN_TRI |
WM831X_GPN_FN_MASK, val);
if (ret < 0)
return ret;
/* Can only set GPIO state once it's in output mode */
wm831x_gpio_set(chip, offset, value);
return 0;
}
static int wm831x_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
{
struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
struct wm831x *wm831x = wm831x_gpio->wm831x;
return irq_create_mapping(wm831x->irq_domain,
WM831X_IRQ_GPIO_1 + offset);
}
static int wm831x_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
unsigned debounce)
{
struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
struct wm831x *wm831x = wm831x_gpio->wm831x;
int reg = WM831X_GPIO1_CONTROL + offset;
int ret, fn;
ret = wm831x_reg_read(wm831x, reg);
if (ret < 0)
return ret;
switch (ret & WM831X_GPN_FN_MASK) {
case 0:
case 1:
break;
default:
/* Not in GPIO mode */
return -EBUSY;
}
if (debounce >= 32 && debounce <= 64)
fn = 0;
else if (debounce >= 4000 && debounce <= 8000)
fn = 1;
else
return -EINVAL;
return wm831x_set_bits(wm831x, reg, WM831X_GPN_FN_MASK, fn);
}
static int wm831x_set_single_ended(struct gpio_chip *chip,
unsigned int offset,
enum single_ended_mode mode)
{
struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
struct wm831x *wm831x = wm831x_gpio->wm831x;
int reg = WM831X_GPIO1_CONTROL + offset;
switch (mode) {
case LINE_MODE_OPEN_DRAIN:
return wm831x_set_bits(wm831x, reg,
WM831X_GPN_OD_MASK, WM831X_GPN_OD);
case LINE_MODE_PUSH_PULL:
return wm831x_set_bits(wm831x, reg,
WM831X_GPN_OD_MASK, 0);
default:
break;
}
return -ENOTSUPP;
}
#ifdef CONFIG_DEBUG_FS
static void wm831x_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
struct wm831x *wm831x = wm831x_gpio->wm831x;
int i, tristated;
for (i = 0; i < chip->ngpio; i++) {
int gpio = i + chip->base;
int reg;
const char *label, *pull, *powerdomain;
/* We report the GPIO even if it's not requested since
* we're also reporting things like alternate
* functions which apply even when the GPIO is not in
* use as a GPIO.
*/
label = gpiochip_is_requested(chip, i);
if (!label)
label = "Unrequested";
seq_printf(s, " gpio-%-3d (%-20.20s) ", gpio, label);
reg = wm831x_reg_read(wm831x, WM831X_GPIO1_CONTROL + i);
if (reg < 0) {
dev_err(wm831x->dev,
"GPIO control %d read failed: %d\n",
gpio, reg);
seq_printf(s, "\n");
continue;
}
switch (reg & WM831X_GPN_PULL_MASK) {
case WM831X_GPIO_PULL_NONE:
pull = "nopull";
break;
case WM831X_GPIO_PULL_DOWN:
pull = "pulldown";
break;
case WM831X_GPIO_PULL_UP:
pull = "pullup";
break;
default:
pull = "INVALID PULL";
break;
}
switch (i + 1) {
case 1 ... 3:
case 7 ... 9:
if (reg & WM831X_GPN_PWR_DOM)
powerdomain = "VPMIC";
else
powerdomain = "DBVDD";
break;
case 4 ... 6:
case 10 ... 12:
if (reg & WM831X_GPN_PWR_DOM)
powerdomain = "SYSVDD";
else
powerdomain = "DBVDD";
break;
case 13 ... 16:
powerdomain = "TPVDD";
break;
default:
BUG();
break;
}
tristated = reg & WM831X_GPN_TRI;
if (wm831x->has_gpio_ena)
tristated = !tristated;
seq_printf(s, " %s %s %s %s%s\n"
" %s%s (0x%4x)\n",
reg & WM831X_GPN_DIR ? "in" : "out",
wm831x_gpio_get(chip, i) ? "high" : "low",
pull,
powerdomain,
reg & WM831X_GPN_POL ? "" : " inverted",
reg & WM831X_GPN_OD ? "open-drain" : "push-pull",
tristated ? " tristated" : "",
reg);
}
}
#else
#define wm831x_gpio_dbg_show NULL
#endif
static struct gpio_chip template_chip = {
.label = "wm831x",
.owner = THIS_MODULE,
.direction_input = wm831x_gpio_direction_in,
.get = wm831x_gpio_get,
.direction_output = wm831x_gpio_direction_out,
.set = wm831x_gpio_set,
.to_irq = wm831x_gpio_to_irq,
.set_debounce = wm831x_gpio_set_debounce,
.set_single_ended = wm831x_set_single_ended,
.dbg_show = wm831x_gpio_dbg_show,
.can_sleep = true,
};
static int wm831x_gpio_probe(struct platform_device *pdev)
{
struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
struct wm831x_pdata *pdata = dev_get_platdata(wm831x->dev);
struct wm831x_gpio *wm831x_gpio;
int ret;
wm831x_gpio = devm_kzalloc(&pdev->dev, sizeof(*wm831x_gpio),
GFP_KERNEL);
if (wm831x_gpio == NULL)
return -ENOMEM;
wm831x_gpio->wm831x = wm831x;
wm831x_gpio->gpio_chip = template_chip;
wm831x_gpio->gpio_chip.ngpio = wm831x->num_gpio;
wm831x_gpio->gpio_chip.parent = &pdev->dev;
if (pdata && pdata->gpio_base)
wm831x_gpio->gpio_chip.base = pdata->gpio_base;
else
wm831x_gpio->gpio_chip.base = -1;
ret = devm_gpiochip_add_data(&pdev->dev, &wm831x_gpio->gpio_chip,
wm831x_gpio);
if (ret < 0) {
dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, wm831x_gpio);
return ret;
}
static struct platform_driver wm831x_gpio_driver = {
.driver.name = "wm831x-gpio",
.driver.owner = THIS_MODULE,
.probe = wm831x_gpio_probe,
};
static int __init wm831x_gpio_init(void)
{
return platform_driver_register(&wm831x_gpio_driver);
}
subsys_initcall(wm831x_gpio_init);
static void __exit wm831x_gpio_exit(void)
{
platform_driver_unregister(&wm831x_gpio_driver);
}
module_exit(wm831x_gpio_exit);
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("GPIO interface for WM831x PMICs");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-gpio");
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