--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff