Commit 703b288f authored by Matti Vaittinen's avatar Matti Vaittinen Committed by Lee Jones
Browse files

gpio: Support ROHM BD71815 GPOs 



Support GPO(s) found from ROHM BD71815 power management IC. The IC has two
GPO pins but only one is properly documented in the data-sheet. The driver
exposes by default only the documented GPO. The second GPO is connected to
E5 pin and is marked as GND in the data-sheet. Control for this
undocumented pin can be enabled using a special DT property.

This driver is derived from work by Peter Yang <yanglsh@embest-tech.com>
although not so much of the original is left.

Signed-off-by: default avatarMatti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 4dcdcfd5

drivers/gpio/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -1105,6 +1105,16 @@ config GPIO_BD70528 
	  This driver can also be built as a module. If so, the module

	  will be called gpio-bd70528.



config GPIO_BD71815

	tristate "ROHM BD71815 PMIC GPIO support"

	depends on MFD_ROHM_BD71828

	help

	  Support for GPO(s) on ROHM BD71815 PMIC. There are two GPOs

	  available on the ROHM PMIC.



	  This driver can also be built as a module. If so, the module

	  will be called gpio-bd71815.



config GPIO_BD71828

	tristate "ROHM BD71828 GPIO support"

	depends on MFD_ROHM_BD71828

drivers/gpio/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ obj-$(CONFIG_GPIO_ATH79) += gpio-ath79.o 
obj-$(CONFIG_GPIO_BCM_KONA)		+= gpio-bcm-kona.o

obj-$(CONFIG_GPIO_BCM_XGS_IPROC)	+= gpio-xgs-iproc.o

obj-$(CONFIG_GPIO_BD70528)		+= gpio-bd70528.o

obj-$(CONFIG_GPIO_BD71815)		+= gpio-bd71815.o

obj-$(CONFIG_GPIO_BD71828)		+= gpio-bd71828.o

obj-$(CONFIG_GPIO_BD9571MWV)		+= gpio-bd9571mwv.o

obj-$(CONFIG_GPIO_BRCMSTB)		+= gpio-brcmstb.o

drivers/gpio/gpio-bd71815.c

0 → 100644
+185 −0
Original line number Diff line number Diff line 
// 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");