[PATCH v2 10/17] gpio: support ROHM BD71815 GPOs

Matti Vaittinen
2021-01-19T07:24:56Z

Support GPO(s) found from ROHM BD71815 power management IC. The IC has two
GPO pins but only one is properly documented in 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 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 original is left.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
---
Changes since v1:
- removed unneeded headers
- clarified dev/parent->dev usage
- removed forgotten #define DEBUG

drivers/gpio/Kconfig | 10 +++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-bd71815.c | 171 ++++++++++++++++++++++++++++++++++++
3 files changed, 182 insertions(+)
create mode 100644 drivers/gpio/gpio-bd71815.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index c70f46e80a3b..fd7283af858d 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1096,6 +1096,16 @@ 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 35e3b6026665..86bb680522a6 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..664de5f69bf1
--- /dev/null
+++ b/drivers/gpio/gpio-bd71815.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Support to GPOs on ROHM BD71815
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/gpio/driver.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+/* For the BD71815 register definitions */
+#include <linux/mfd/rohm-bd71815.h>
+
+struct bd71815_gpio {
+ struct gpio_chip chip;
+ struct device *dev;
+ struct regmap *regmap;
+ /*
+ * 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 pin
+ * is marked as GND on the data-sheet. The functionality is still there
+ * though! I guess driving GPO connected to 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".
+ */
+ bool e5_pin_is_gpo;
+};
+
+static int bd71815gpo_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct bd71815_gpio *bd71815 = gpiochip_get_data(chip);
+ int ret = 0;
+ int 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, val, mask;
+
+ if (!bd71815->e5_pin_is_gpo && offset)
+ return;
+
+ mask = BIT(offset);
+ val = value ? mask : 0;
+ ret = regmap_update_bits(bd71815->regmap, BD71815_REG_GPO, mask, val);
+ 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);
+
+ if (!bdgpio->e5_pin_is_gpo && offset)
+ return -EOPNOTSUPP;
+
+ 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 -EOPNOTSUPP;
+}
+
+/* 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 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 = 1,
+};
+
+static int gpo_bd71815_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct bd71815_gpio *g;
+ struct device *dev;
+ struct device *parent;
+
+ /*
+ * 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->e5_pin_is_gpo = of_property_read_bool(parent->of_node,
+ "rohm,enable-hidden-gpo");
+ g->chip = bd71815gpo_chip;
+ g->chip.base = -1;
+
+ if (g->e5_pin_is_gpo)
+ g->chip.ngpio = 2;
+ else
+ g->chip.ngpio = 1;
+
+ g->chip.parent = parent;
+ g->chip.of_node = parent->of_node;
+ g->regmap = dev_get_regmap(parent, NULL);
+ g->dev = dev;
+
+ ret = devm_gpiochip_add_data(dev, &g->chip, g);
+ if (ret < 0) {
+ dev_err(dev, "could not register gpiochip, %d\n", ret);
+ return ret;
+ }
+
+ return ret;
+}
+static const struct platform_device_id bd7181x_gpo_id[] = {
+ { "bd71815-gpo" },
+ { },
+};
+MODULE_DEVICE_TABLE(platform, bd7181x_gpo_id);
+
+static struct platform_driver gpo_bd71815_driver = {
+ .driver = {
+ .name = "bd71815-gpo",
+ .owner = THIS_MODULE,
+ },
+ .probe = gpo_bd71815_probe,
+ .id_table = bd7181x_gpo_id,
+};
+
+module_platform_driver(gpo_bd71815_driver);
+
+/* Note: this hardware lives inside an I2C-based multi-function device. */
+MODULE_ALIAS("platform:bd71815-gpo");
+
+MODULE_AUTHOR("Peter Yang <yanglsh@embest-tech.com>");
+MODULE_DESCRIPTION("GPO interface for BD71815");
+MODULE_LICENSE("GPL");
--
2.25.4

--
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]