[PATCH v6 09/16] gpio: support ROHM BD71815 GPOs

Matti Vaittinen
2021-04-05T11:43:19Z

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>
---
Changes since v5:
- more styling fixes
- corrected commit message spelling
- dropped error print as was suggested by Andy
- dropped explicit setting of the .owner in driver struct

drivers/gpio/Kconfig | 10 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-bd71815.c | 185 ++++++++++++++++++++++++++++++++++++
3 files changed, 196 insertions(+)
create mode 100644 drivers/gpio/gpio-bd71815.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e3607ec4c2e8..d3b3de514f6e 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -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
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index c58a90a3c3b1..4c12f31db31f 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -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
diff --git a/drivers/gpio/gpio-bd71815.c b/drivers/gpio/gpio-bd71815.c
new file mode 100644
index 000000000000..d7dcb3395a77
--- /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");