diff options
Diffstat (limited to 'drivers/gpio/gpio-bd71815.c')
| -rw-r--r-- | drivers/gpio/gpio-bd71815.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-bd71815.c b/drivers/gpio/gpio-bd71815.c new file mode 100644 index 0000000000..08ff285725 --- /dev/null +++ b/drivers/gpio/gpio-bd71815.c @@ -0,0 +1,185 @@ +// 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"); |