gpio: Initial support for ROHM bd70528 GPIO block

ROHM BD70528 PMIC has 4 GPIO pins. Allow them to be
controlled by GPIO framework.

IRQs are handled by regmap-irq and GPIO driver is not
aware of the irq usage.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 8023d03..87dbbd0 100644 (file)
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -977,6 +977,17 @@ config GPIO_ARIZONA
        help
          Support for GPIOs on Wolfson Arizona class devices.
 
+config GPIO_BD70528
+       tristate "ROHM BD70528 GPIO support"
+       depends on MFD_ROHM_BD70528
+       help
+         Support for GPIOs on ROHM BD70528 PMIC. There are four GPIOs
+         available on the ROHM PMIC in total. The GPIOs can also
+         generate interrupts.
+
+         This driver can also be built as a module. If so, the module
+         will be called gpio-bd70528.
+
 config GPIO_BD9571MWV
        tristate "ROHM BD9571 GPIO support"
        depends on MFD_BD9571MWV

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 6700eee..10efc4f 100644 (file)
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_GPIO_ATH79)      += gpio-ath79.o
 obj-$(CONFIG_GPIO_ASPEED)      += gpio-aspeed.o
 obj-$(CONFIG_GPIO_RASPBERRYPI_EXP)     += gpio-raspberrypi-exp.o
 obj-$(CONFIG_GPIO_BCM_KONA)    += gpio-bcm-kona.o
+obj-$(CONFIG_GPIO_BD70528)     += gpio-bd70528.o
 obj-$(CONFIG_GPIO_BD9571MWV)   += gpio-bd9571mwv.o
 obj-$(CONFIG_GPIO_BRCMSTB)     += gpio-brcmstb.o
 obj-$(CONFIG_GPIO_BT8XX)       += gpio-bt8xx.o

diff --git a/drivers/gpio/gpio-bd70528.c b/drivers/gpio/gpio-bd70528.c
new file mode 100644 (file)
index 0000000..fd85605
--- /dev/null
+++ b/drivers/gpio/gpio-bd70528.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 ROHM Semiconductors
+// gpio-bd70528.c ROHM BD70528MWV gpio driver
+
+#include <linux/gpio/driver.h>
+#include <linux/mfd/rohm-bd70528.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define GPIO_IN_REG(offset) (BD70528_REG_GPIO1_IN + (offset) * 2)
+#define GPIO_OUT_REG(offset) (BD70528_REG_GPIO1_OUT + (offset) * 2)
+
+struct bd70528_gpio {
+       struct rohm_regmap_dev chip;
+       struct gpio_chip gpio;
+};
+
+static int bd70528_set_debounce(struct bd70528_gpio *bdgpio,
+                               unsigned int offset, unsigned int debounce)
+{
+       u8 val;
+
+       switch (debounce) {
+       case 0:
+               val = BD70528_DEBOUNCE_DISABLE;
+               break;
+       case 1 ... 15:
+               val = BD70528_DEBOUNCE_15MS;
+               break;
+       case 16 ... 30:
+               val = BD70528_DEBOUNCE_30MS;
+               break;
+       case 31 ... 50:
+               val = BD70528_DEBOUNCE_50MS;
+               break;
+       default:
+               dev_err(bdgpio->chip.dev,
+                       "Invalid debouce value %u\n", debounce);
+               return -EINVAL;
+       }
+       return regmap_update_bits(bdgpio->chip.regmap, GPIO_IN_REG(offset),
+                                BD70528_DEBOUNCE_MASK, val);
+}
+
+static int bd70528_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+       struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
+       int val, ret;
+
+       /* Do we need to do something to IRQs here? */
+       ret = regmap_read(bdgpio->chip.regmap, GPIO_OUT_REG(offset), &val);
+       if (ret) {
+               dev_err(bdgpio->chip.dev, "Could not read gpio direction\n");
+               return ret;
+       }
+
+       return !(val & BD70528_GPIO_OUT_EN_MASK);
+}
+
+static int bd70528_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
+                                  unsigned long config)
+{
+       struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
+
+       switch (pinconf_to_config_param(config)) {
+       case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+               return regmap_update_bits(bdgpio->chip.regmap,
+                                         GPIO_OUT_REG(offset),
+                                         BD70528_GPIO_DRIVE_MASK,
+                                         BD70528_GPIO_OPEN_DRAIN);
+               break;
+       case PIN_CONFIG_DRIVE_PUSH_PULL:
+               return regmap_update_bits(bdgpio->chip.regmap,
+                                         GPIO_OUT_REG(offset),
+                                         BD70528_GPIO_DRIVE_MASK,
+                                         BD70528_GPIO_PUSH_PULL);
+               break;
+       case PIN_CONFIG_INPUT_DEBOUNCE:
+               return bd70528_set_debounce(bdgpio, offset,
+                                           pinconf_to_config_argument(config));
+               break;
+       default:
+               break;
+       }
+       return -ENOTSUPP;
+}
+
+static int bd70528_direction_input(struct gpio_chip *chip, unsigned int offset)
+{
+       struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
+
+       /* Do we need to do something to IRQs here? */
+       return regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
+                                BD70528_GPIO_OUT_EN_MASK,
+                                BD70528_GPIO_OUT_DISABLE);
+}
+
+static void bd70528_gpio_set(struct gpio_chip *chip, unsigned int offset,
+                            int value)
+{
+       int ret;
+       struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
+       u8 val = (value) ? BD70528_GPIO_OUT_HI : BD70528_GPIO_OUT_LO;
+
+       ret = regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
+                                BD70528_GPIO_OUT_MASK, val);
+       if (ret)
+               dev_err(bdgpio->chip.dev, "Could not set gpio to %d\n", value);
+}
+
+static int bd70528_direction_output(struct gpio_chip *chip, unsigned int offset,
+                                   int value)
+{
+       struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
+
+       bd70528_gpio_set(chip, offset, value);
+       return regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
+                                BD70528_GPIO_OUT_EN_MASK,
+                                BD70528_GPIO_OUT_ENABLE);
+}
+
+#define GPIO_IN_STATE_MASK(offset) (BD70528_GPIO_IN_STATE_BASE << (offset))
+
+static int bd70528_gpio_get_o(struct bd70528_gpio *bdgpio, unsigned int offset)
+{
+       int ret;
+       unsigned int val;
+
+       ret = regmap_read(bdgpio->chip.regmap, GPIO_OUT_REG(offset), &val);
+       if (!ret)
+               ret = !!(val & BD70528_GPIO_OUT_MASK);
+       else
+               dev_err(bdgpio->chip.dev, "GPIO (out) state read failed\n");
+
+       return ret;
+}
+
+static int bd70528_gpio_get_i(struct bd70528_gpio *bdgpio, unsigned int offset)
+{
+       unsigned int val;
+       int ret;
+
+       ret = regmap_read(bdgpio->chip.regmap, BD70528_REG_GPIO_STATE, &val);
+
+       if (!ret)
+               ret = !(val & GPIO_IN_STATE_MASK(offset));
+       else
+               dev_err(bdgpio->chip.dev, "GPIO (in) state read failed\n");
+
+       return ret;
+}
+
+static int bd70528_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+       int ret = -EINVAL;
+       struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
+
+       /*
+        * There is a race condition where someone might be changing the
+        * GPIO direction after we get it but before we read the value. But
+        * application design where GPIO direction may be changed just when
+        * we read GPIO value would be pointless as reader could not know
+        * whether the returned high/low state is caused by input or output.
+        * Or then there must be other ways to mitigate the issue. Thus
+        * locking would make no sense.
+        */
+       ret = bd70528_get_direction(chip, offset);
+       if (ret == 0)
+               ret = bd70528_gpio_get_o(bdgpio, offset);
+       else if (ret == 1)
+               ret = bd70528_gpio_get_i(bdgpio, offset);
+       else
+               dev_err(bdgpio->chip.dev, "failed to read GPIO direction\n");
+
+       return ret;
+}
+
+static int bd70528_probe(struct platform_device *pdev)
+{
+       struct bd70528_gpio *bdgpio;
+       struct rohm_regmap_dev *bd70528;
+       int ret;
+
+       bd70528 = dev_get_drvdata(pdev->dev.parent);
+       if (!bd70528) {
+               dev_err(&pdev->dev, "No MFD driver data\n");
+               return -EINVAL;
+       }
+
+       bdgpio = devm_kzalloc(&pdev->dev, sizeof(*bdgpio),
+                             GFP_KERNEL);
+       if (!bdgpio)
+               return -ENOMEM;
+       bdgpio->chip.dev = &pdev->dev;
+       bdgpio->gpio.parent = pdev->dev.parent;
+       bdgpio->gpio.label = "bd70528-gpio";
+       bdgpio->gpio.owner = THIS_MODULE;
+       bdgpio->gpio.get_direction = bd70528_get_direction;
+       bdgpio->gpio.direction_input = bd70528_direction_input;
+       bdgpio->gpio.direction_output = bd70528_direction_output;
+       bdgpio->gpio.set_config = bd70528_gpio_set_config;
+       bdgpio->gpio.can_sleep = true;
+       bdgpio->gpio.get = bd70528_gpio_get;
+       bdgpio->gpio.set = bd70528_gpio_set;
+       bdgpio->gpio.ngpio = 4;
+       bdgpio->gpio.base = -1;
+#ifdef CONFIG_OF_GPIO
+       bdgpio->gpio.of_node = pdev->dev.parent->of_node;
+#endif
+       bdgpio->chip.regmap = bd70528->regmap;
+
+       ret = devm_gpiochip_add_data(&pdev->dev, &bdgpio->gpio,
+                                    bdgpio);
+       if (ret)
+               dev_err(&pdev->dev, "gpio_init: Failed to add bd70528-gpio\n");
+
+       return ret;
+}
+
+static struct platform_driver bd70528_gpio = {
+       .driver = {
+               .name = "bd70528-gpio"
+       },
+       .probe = bd70528_probe,
+};
+
+module_platform_driver(bd70528_gpio);
+
+MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
+MODULE_DESCRIPTION("BD70528 voltage regulator driver");
+MODULE_LICENSE("GPL");