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// SPDX-License-Identifier: GPL-2.0
/*
* Support to GPOs on ROHM BD71815
* Copyright 2021 ROHM Semiconductors.
* Author: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
*
* Copyright 2014 Embest Technology Co. Ltd. Inc.
* Author: yanglsh@embest-tech.com
*/
#include <linux/gpio/driver.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
/* For the BD71815 register definitions */
#include <linux/mfd/rohm-bd71815.h>
struct bd71815_gpio {
/* chip.parent points the MFD which provides DT node and regmap */
struct gpio_chip chip;
/* dev points to the platform device for devm and prints */
struct device *dev;
struct regmap *regmap;
};
static int bd71815gpo_get(struct gpio_chip *chip, unsigned int offset)
{
struct bd71815_gpio *bd71815 = gpiochip_get_data(chip);
int ret, val;
ret = regmap_read(bd71815->regmap, BD71815_REG_GPO, &val);
if (ret)
return ret;
return (val >> offset) & 1;
}
static void bd71815gpo_set(struct gpio_chip *chip, unsigned int offset,
int value)
{
struct bd71815_gpio *bd71815 = gpiochip_get_data(chip);
int ret, bit;
bit = BIT(offset);
if (value)
ret = regmap_set_bits(bd71815->regmap, BD71815_REG_GPO, bit);
else
ret = regmap_clear_bits(bd71815->regmap, BD71815_REG_GPO, bit);
if (ret)
dev_warn(bd71815->dev, "failed to toggle GPO\n");
}
static int bd71815_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
unsigned long config)
{
struct bd71815_gpio *bdgpio = gpiochip_get_data(chip);
switch (pinconf_to_config_param(config)) {
case PIN_CONFIG_DRIVE_OPEN_DRAIN:
return regmap_update_bits(bdgpio->regmap,
BD71815_REG_GPO,
BD71815_GPIO_DRIVE_MASK << offset,
BD71815_GPIO_OPEN_DRAIN << offset);
case PIN_CONFIG_DRIVE_PUSH_PULL:
return regmap_update_bits(bdgpio->regmap,
BD71815_REG_GPO,
BD71815_GPIO_DRIVE_MASK << offset,
BD71815_GPIO_CMOS << offset);
default:
break;
}
return -ENOTSUPP;
}
/* BD71815 GPIO is actually GPO */
static int bd71815gpo_direction_get(struct gpio_chip *gc, unsigned int offset)
{
return GPIO_LINE_DIRECTION_OUT;
}
/* Template for GPIO chip */
static const struct gpio_chip bd71815gpo_chip = {
.label = "bd71815",
.owner = THIS_MODULE,
.get = bd71815gpo_get,
.get_direction = bd71815gpo_direction_get,
.set = bd71815gpo_set,
.set_config = bd71815_gpio_set_config,
.can_sleep = true,
};
#define BD71815_TWO_GPIOS GENMASK(1, 0)
#define BD71815_ONE_GPIO BIT(0)
/*
* Sigh. The BD71815 and BD71817 were originally designed to support two GPO
* pins. At some point it was noticed the second GPO pin which is the E5 pin
* located at the center of IC is hard to use on PCB (due to the location). It
* was decided to not promote this second GPO and the pin is marked as GND in
* the datasheet. The functionality is still there though! I guess driving a GPO
* connected to the ground is a bad idea. Thus we do not support it by default.
* OTOH - the original driver written by colleagues at Embest did support
* controlling this second GPO. It is thus possible this is used in some of the
* products.
*
* This driver does not by default support configuring this second GPO
* but allows using it by providing the DT property
* "rohm,enable-hidden-gpo".
*/
static int bd71815_init_valid_mask(struct gpio_chip *gc,
unsigned long *valid_mask,
unsigned int ngpios)
{
if (ngpios != 2)
return 0;
if (gc->parent && device_property_present(gc->parent,
"rohm,enable-hidden-gpo"))
*valid_mask = BD71815_TWO_GPIOS;
else
*valid_mask = BD71815_ONE_GPIO;
return 0;
}
static int gpo_bd71815_probe(struct platform_device *pdev)
{
struct bd71815_gpio *g;
struct device *parent, *dev;
/*
* Bind devm lifetime to this platform device => use dev for devm.
* also the prints should originate from this device.
*/
dev = &pdev->dev;
/* The device-tree and regmap come from MFD => use parent for that */
parent = dev->parent;
g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL);
if (!g)
return -ENOMEM;
g->chip = bd71815gpo_chip;
/*
* FIXME: As writing of this the sysfs interface for GPIO control does
* not respect the valid_mask. Do not trust it but rather set the ngpios
* to 1 if "rohm,enable-hidden-gpo" is not given.
*
* This check can be removed later if the sysfs export is fixed and
* if the fix is backported.
*
* For now it is safest to just set the ngpios though.
*/
if (device_property_present(parent, "rohm,enable-hidden-gpo"))
g->chip.ngpio = 2;
else
g->chip.ngpio = 1;
g->chip.init_valid_mask = bd71815_init_valid_mask;
g->chip.base = -1;
g->chip.parent = parent;
g->regmap = dev_get_regmap(parent, NULL);
g->dev = dev;
return devm_gpiochip_add_data(dev, &g->chip, g);
}
static struct platform_driver gpo_bd71815_driver = {
.driver = {
.name = "bd71815-gpo",
},
.probe = gpo_bd71815_probe,
};
module_platform_driver(gpo_bd71815_driver);
MODULE_ALIAS("platform:bd71815-gpo");
MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
MODULE_AUTHOR("Peter Yang <yanglsh@embest-tech.com>");
MODULE_DESCRIPTION("GPO interface for BD71815");
MODULE_LICENSE("GPL");
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