gpio: lp873x: Add support for General Purpose Outputs

Add driver for lp873x PMIC family GPOs. Two GPOs are supported
and can be configured in Open-drain output or Push-pull output.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

3 files changed, 204 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 98dd47a30fc7..346e9a9b4397 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -874,6 +874,16 @@ config GPIO_LP3943
           LP3943 can be used as a GPIO expander which provides up to 16 GPIOs.
           Open drain outputs are required for this usage.
 
+config GPIO_LP873X
+        tristate "TI LP873X GPO"
+        depends on MFD_TI_LP873X
+        help
+          This driver supports the GPO on TI Lp873x PMICs. 2 GPOs are present
+          on LP873X PMICs.
+
+          This driver can also be built as a module. If so, the module will be
+          called gpio-lp873x.
+
 config GPIO_MAX77620
         tristate "GPIO support for PMIC MAX77620 and MAX20024"
         depends on MFD_MAX77620
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 2a035ed8f168..d60432f2a126 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_GPIO_LOONGSON)	+= gpio-loongson.o
 obj-$(CONFIG_GPIO_LP3943)       += gpio-lp3943.o
 obj-$(CONFIG_GPIO_LPC18XX)      += gpio-lpc18xx.o
 obj-$(CONFIG_ARCH_LPC32XX)      += gpio-lpc32xx.o
+obj-$(CONFIG_GPIO_LP873X)       += gpio-lp873x.o
 obj-$(CONFIG_GPIO_LYNXPOINT)    += gpio-lynxpoint.o
 obj-$(CONFIG_GPIO_MAX730X)      += gpio-max730x.o
 obj-$(CONFIG_GPIO_MAX7300)      += gpio-max7300.o
diff --git a/drivers/gpio/gpio-lp873x.c b/drivers/gpio/gpio-lp873x.c
new file mode 100644
index 000000000000..f10d49da1554
--- /dev/null
+++ b/drivers/gpio/gpio-lp873x.c
@@ -0,0 +1,193 @@
+/*
+ * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
+ *      Keerthy <j-keerthy@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether expressed or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License version 2 for more details.
+ *
+ * Based on the TPS65218 driver
+ */
+
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <linux/mfd/lp873x.h>
+
+#define BITS_PER_GPO            0x4
+#define LP873X_GPO_CTRL_OD      0x2
+
+struct lp873x_gpio {
+        struct gpio_chip chip;
+        struct lp873x *lp873;
+};
+
+static int lp873x_gpio_get_direction(struct gpio_chip *chip,
+                                     unsigned int offset)
+{
+        /* This device is output only */
+        return 0;
+}
+
+static int lp873x_gpio_direction_input(struct gpio_chip *chip,
+                                       unsigned int offset)
+{
+        /* This device is output only */
+        return -EINVAL;
+}
+
+static int lp873x_gpio_direction_output(struct gpio_chip *chip,
+                                        unsigned int offset, int value)
+{
+        struct lp873x_gpio *gpio = gpiochip_get_data(chip);
+
+        /* Set the initial value */
+        return regmap_update_bits(gpio->lp873->regmap, LP873X_REG_GPO_CTRL,
+                                  BIT(offset * BITS_PER_GPO),
+                                  value ? BIT(offset * BITS_PER_GPO) : 0);
+}
+
+static int lp873x_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+        struct lp873x_gpio *gpio = gpiochip_get_data(chip);
+        int ret, val;
+
+        ret = regmap_read(gpio->lp873->regmap, LP873X_REG_GPO_CTRL, &val);
+        if (ret < 0)
+                return ret;
+
+        return val & BIT(offset * BITS_PER_GPO);
+}
+
+static void lp873x_gpio_set(struct gpio_chip *chip, unsigned int offset,
+                            int value)
+{
+        struct lp873x_gpio *gpio = gpiochip_get_data(chip);
+
+        regmap_update_bits(gpio->lp873->regmap, LP873X_REG_GPO_CTRL,
+                           BIT(offset * BITS_PER_GPO),
+                           value ? BIT(offset * BITS_PER_GPO) : 0);
+}
+
+static int lp873x_gpio_request(struct gpio_chip *gc, unsigned int offset)
+{
+        struct lp873x_gpio *gpio = gpiochip_get_data(gc);
+        int ret;
+
+        switch (offset) {
+        case 0:
+                /* No MUX Set up Needed for GPO */
+                break;
+        case 1:
+                /* Setup the CLKIN_PIN_SEL MUX to GPO2 */
+                ret = regmap_update_bits(gpio->lp873->regmap, LP873X_REG_CONFIG,
+                                         LP873X_CONFIG_CLKIN_PIN_SEL, 0);
+                if (ret)
+                        return ret;
+
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static int lp873x_gpio_set_single_ended(struct gpio_chip *gc,
+                                        unsigned int offset,
+                                        enum single_ended_mode mode)
+{
+        struct lp873x_gpio *gpio = gpiochip_get_data(gc);
+
+        switch (mode) {
+        case LINE_MODE_OPEN_DRAIN:
+                return regmap_update_bits(gpio->lp873->regmap,
+                                          LP873X_REG_GPO_CTRL,
+                                          BIT(offset * BITS_PER_GPO +
+                                          LP873X_GPO_CTRL_OD),
+                                          BIT(offset * BITS_PER_GPO +
+                                          LP873X_GPO_CTRL_OD));
+        case LINE_MODE_PUSH_PULL:
+                return regmap_update_bits(gpio->lp873->regmap,
+                                          LP873X_REG_GPO_CTRL,
+                                          BIT(offset * BITS_PER_GPO +
+                                          LP873X_GPO_CTRL_OD), 0);
+        default:
+                return -ENOTSUPP;
+        }
+}
+
+static struct gpio_chip template_chip = {
+        .label                  = "lp873x-gpio",
+        .owner                  = THIS_MODULE,
+        .request                = lp873x_gpio_request,
+        .get_direction          = lp873x_gpio_get_direction,
+        .direction_input        = lp873x_gpio_direction_input,
+        .direction_output       = lp873x_gpio_direction_output,
+        .get                    = lp873x_gpio_get,
+        .set                    = lp873x_gpio_set,
+        .set_single_ended       = lp873x_gpio_set_single_ended,
+        .base                   = -1,
+        .ngpio                  = 2,
+        .can_sleep              = true,
+};
+
+static int lp873x_gpio_probe(struct platform_device *pdev)
+{
+        struct lp873x_gpio *gpio;
+        int ret;
+
+        gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+        if (!gpio)
+                return -ENOMEM;
+
+        platform_set_drvdata(pdev, gpio);
+
+        gpio->lp873 = dev_get_drvdata(pdev->dev.parent);
+        gpio->chip = template_chip;
+        gpio->chip.parent = gpio->lp873->dev;
+
+        ret = gpiochip_add_data(&gpio->chip, gpio);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
+                return ret;
+        }
+
+        return 0;
+}
+
+static int lp873x_gpio_remove(struct platform_device *pdev)
+{
+        struct lp873x_gpio *gpio = platform_get_drvdata(pdev);
+
+        gpiochip_remove(&gpio->chip);
+
+        return 0;
+}
+
+static const struct platform_device_id lp873x_gpio_id_table[] = {
+        { "lp873x-gpio", },
+        { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, lp873x_gpio_id_table);
+
+static struct platform_driver lp873x_gpio_driver = {
+        .driver = {
+                .name = "lp873x-gpio",
+        },
+        .probe = lp873x_gpio_probe,
+        .remove = lp873x_gpio_remove,
+        .id_table = lp873x_gpio_id_table,
+};
+module_platform_driver(lp873x_gpio_driver);
+
+MODULE_AUTHOR("Keerthy <j-keerthy@ti.com>");
+MODULE_DESCRIPTION("LP873X GPIO driver");
+MODULE_LICENSE("GPL v2");