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