Initial import

1 files changed, 242 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-lp3943.c b/drivers/gpio/gpio-lp3943.c
new file mode 100644
index 000000000..cfc5b12b4
--- /dev/null
+++ b/drivers/gpio/gpio-lp3943.c
@@ -0,0 +1,242 @@
+/*
+ * TI/National Semiconductor LP3943 GPIO driver
+ *
+ * Copyright 2013 Texas Instruments
+ *
+ * Author: Milo Kim <milo.kim@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2.
+ */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/mfd/lp3943.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+enum lp3943_gpios {
+	LP3943_GPIO1,
+	LP3943_GPIO2,
+	LP3943_GPIO3,
+	LP3943_GPIO4,
+	LP3943_GPIO5,
+	LP3943_GPIO6,
+	LP3943_GPIO7,
+	LP3943_GPIO8,
+	LP3943_GPIO9,
+	LP3943_GPIO10,
+	LP3943_GPIO11,
+	LP3943_GPIO12,
+	LP3943_GPIO13,
+	LP3943_GPIO14,
+	LP3943_GPIO15,
+	LP3943_GPIO16,
+	LP3943_MAX_GPIO,
+};
+
+struct lp3943_gpio {
+	struct gpio_chip chip;
+	struct lp3943 *lp3943;
+	u16 input_mask;		/* 1 = GPIO is input direction, 0 = output */
+};
+
+static inline struct lp3943_gpio *to_lp3943_gpio(struct gpio_chip *_chip)
+{
+	return container_of(_chip, struct lp3943_gpio, chip);
+}
+
+static int lp3943_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
+	struct lp3943 *lp3943 = lp3943_gpio->lp3943;
+
+	/* Return an error if the pin is already assigned */
+	if (test_and_set_bit(offset, &lp3943->pin_used))
+		return -EBUSY;
+
+	return 0;
+}
+
+static void lp3943_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
+	struct lp3943 *lp3943 = lp3943_gpio->lp3943;
+
+	clear_bit(offset, &lp3943->pin_used);
+}
+
+static int lp3943_gpio_set_mode(struct lp3943_gpio *lp3943_gpio, u8 offset,
+				u8 val)
+{
+	struct lp3943 *lp3943 = lp3943_gpio->lp3943;
+	const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
+
+	return lp3943_update_bits(lp3943, mux[offset].reg, mux[offset].mask,
+				  val << mux[offset].shift);
+}
+
+static int lp3943_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
+
+	lp3943_gpio->input_mask |= BIT(offset);
+
+	return lp3943_gpio_set_mode(lp3943_gpio, offset, LP3943_GPIO_IN);
+}
+
+static int lp3943_get_gpio_in_status(struct lp3943_gpio *lp3943_gpio,
+				     struct gpio_chip *chip, unsigned offset)
+{
+	u8 addr, read;
+	int err;
+
+	switch (offset) {
+	case LP3943_GPIO1 ... LP3943_GPIO8:
+		addr = LP3943_REG_GPIO_A;
+		break;
+	case LP3943_GPIO9 ... LP3943_GPIO16:
+		addr = LP3943_REG_GPIO_B;
+		offset = offset - 8;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	err = lp3943_read_byte(lp3943_gpio->lp3943, addr, &read);
+	if (err)
+		return err;
+
+	return !!(read & BIT(offset));
+}
+
+static int lp3943_get_gpio_out_status(struct lp3943_gpio *lp3943_gpio,
+				      struct gpio_chip *chip, unsigned offset)
+{
+	struct lp3943 *lp3943 = lp3943_gpio->lp3943;
+	const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
+	u8 read;
+	int err;
+
+	err = lp3943_read_byte(lp3943, mux[offset].reg, &read);
+	if (err)
+		return err;
+
+	read = (read & mux[offset].mask) >> mux[offset].shift;
+
+	if (read == LP3943_GPIO_OUT_HIGH)
+		return 1;
+	else if (read == LP3943_GPIO_OUT_LOW)
+		return 0;
+	else
+		return -EINVAL;
+}
+
+static int lp3943_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
+
+	/*
+	 * Limitation:
+	 *   LP3943 doesn't have the GPIO direction register. It provides
+	 *   only input and output status registers.
+	 *   So, direction info is required to handle the 'get' operation.
+	 *   This variable is updated whenever the direction is changed and
+	 *   it is used here.
+	 */
+
+	if (lp3943_gpio->input_mask & BIT(offset))
+		return lp3943_get_gpio_in_status(lp3943_gpio, chip, offset);
+	else
+		return lp3943_get_gpio_out_status(lp3943_gpio, chip, offset);
+}
+
+static void lp3943_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
+	u8 data;
+
+	if (value)
+		data = LP3943_GPIO_OUT_HIGH;
+	else
+		data = LP3943_GPIO_OUT_LOW;
+
+	lp3943_gpio_set_mode(lp3943_gpio, offset, data);
+}
+
+static int lp3943_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
+					int value)
+{
+	struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip);
+
+	lp3943_gpio_set(chip, offset, value);
+	lp3943_gpio->input_mask &= ~BIT(offset);
+
+	return 0;
+}
+
+static const struct gpio_chip lp3943_gpio_chip = {
+	.label			= "lp3943",
+	.owner			= THIS_MODULE,
+	.request		= lp3943_gpio_request,
+	.free			= lp3943_gpio_free,
+	.direction_input	= lp3943_gpio_direction_input,
+	.get			= lp3943_gpio_get,
+	.direction_output	= lp3943_gpio_direction_output,
+	.set			= lp3943_gpio_set,
+	.base			= -1,
+	.ngpio			= LP3943_MAX_GPIO,
+	.can_sleep		= 1,
+};
+
+static int lp3943_gpio_probe(struct platform_device *pdev)
+{
+	struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
+	struct lp3943_gpio *lp3943_gpio;
+
+	lp3943_gpio = devm_kzalloc(&pdev->dev, sizeof(*lp3943_gpio),
+				GFP_KERNEL);
+	if (!lp3943_gpio)
+		return -ENOMEM;
+
+	lp3943_gpio->lp3943 = lp3943;
+	lp3943_gpio->chip = lp3943_gpio_chip;
+	lp3943_gpio->chip.dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, lp3943_gpio);
+
+	return gpiochip_add(&lp3943_gpio->chip);
+}
+
+static int lp3943_gpio_remove(struct platform_device *pdev)
+{
+	struct lp3943_gpio *lp3943_gpio = platform_get_drvdata(pdev);
+
+	gpiochip_remove(&lp3943_gpio->chip);
+	return 0;
+}
+
+static const struct of_device_id lp3943_gpio_of_match[] = {
+	{ .compatible = "ti,lp3943-gpio", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, lp3943_gpio_of_match);
+
+static struct platform_driver lp3943_gpio_driver = {
+	.probe = lp3943_gpio_probe,
+	.remove = lp3943_gpio_remove,
+	.driver = {
+		.name = "lp3943-gpio",
+		.of_match_table = lp3943_gpio_of_match,
+	},
+};
+module_platform_driver(lp3943_gpio_driver);
+
+MODULE_DESCRIPTION("LP3943 GPIO driver");
+MODULE_ALIAS("platform:lp3943-gpio");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL");