gpio: Kontron PLD gpio driver
Add gpio support for the on-board PLD found on some Kontron embedded modules.
Originally-from: Michael Brunner <michael.brunner@kontron.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kevin Strasser <kevin.strasser@linux.intel.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-kempld.c b/drivers/gpio/gpio-kempld.c
new file mode 100644
index 0000000..1bdc3a2
--- /dev/null
+++ b/drivers/gpio/gpio-kempld.c
@@ -0,0 +1,225 @@
+/*
+ * Kontron PLD GPIO driver
+ *
+ * Copyright (c) 2010-2013 Kontron Europe GmbH
+ * Author: Michael Brunner <michael.brunner@kontron.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/mfd/kempld.h>
+
+#define KEMPLD_GPIO_MAX_NUM 16
+#define KEMPLD_GPIO_MASK(x) (1 << ((x) % 8))
+#define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8)
+#define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8)
+#define KEMPLD_GPIO_EVT_LVL_EDGE 0x46
+#define KEMPLD_GPIO_IEN 0x4A
+
+struct kempld_gpio_data {
+ struct gpio_chip chip;
+ struct kempld_device_data *pld;
+};
+
+/*
+ * Set or clear GPIO bit
+ * kempld_get_mutex must be called prior to calling this function.
+ */
+static void kempld_gpio_bitop(struct kempld_device_data *pld,
+ u8 reg, u8 bit, u8 val)
+{
+ u8 status;
+
+ status = kempld_read8(pld, reg);
+ if (val)
+ status |= (1 << bit);
+ else
+ status &= ~(1 << bit);
+ kempld_write8(pld, reg, status);
+}
+
+static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit)
+{
+ u8 status;
+
+ kempld_get_mutex(pld);
+ status = kempld_read8(pld, reg);
+ kempld_release_mutex(pld);
+
+ return !!(status & (1 << bit));
+}
+
+static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+ struct kempld_gpio_data *gpio
+ = container_of(chip, struct kempld_gpio_data, chip);
+ struct kempld_device_data *pld = gpio->pld;
+
+ return kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset),
+ KEMPLD_GPIO_MASK(offset));
+}
+
+static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+ struct kempld_gpio_data *gpio
+ = container_of(chip, struct kempld_gpio_data, chip);
+ struct kempld_device_data *pld = gpio->pld;
+
+ kempld_get_mutex(pld);
+ kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset),
+ KEMPLD_GPIO_MASK(offset), value);
+ kempld_release_mutex(pld);
+}
+
+static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+ struct kempld_gpio_data *gpio
+ = container_of(chip, struct kempld_gpio_data, chip);
+ struct kempld_device_data *pld = gpio->pld;
+
+ kempld_get_mutex(pld);
+ kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset),
+ KEMPLD_GPIO_MASK(offset), 0);
+ kempld_release_mutex(pld);
+
+ return 0;
+}
+
+static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
+ int value)
+{
+ struct kempld_gpio_data *gpio
+ = container_of(chip, struct kempld_gpio_data, chip);
+ struct kempld_device_data *pld = gpio->pld;
+
+ kempld_get_mutex(pld);
+ kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset),
+ KEMPLD_GPIO_MASK(offset), value);
+ kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset),
+ KEMPLD_GPIO_MASK(offset), 1);
+ kempld_release_mutex(pld);
+
+ return 0;
+}
+
+static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+ struct kempld_gpio_data *gpio
+ = container_of(chip, struct kempld_gpio_data, chip);
+ struct kempld_device_data *pld = gpio->pld;
+
+ return kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset),
+ KEMPLD_GPIO_MASK(offset));
+}
+
+static int kempld_gpio_pincount(struct kempld_device_data *pld)
+{
+ u16 evt, evt_back;
+
+ kempld_get_mutex(pld);
+
+ /* Backup event register as it might be already initialized */
+ evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
+ /* Clear event register */
+ kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);
+ /* Read back event register */
+ evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
+ /* Restore event register */
+ kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);
+
+ kempld_release_mutex(pld);
+
+ return evt ? __ffs(evt) : 16;
+}
+
+static int kempld_gpio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct kempld_device_data *pld = dev_get_drvdata(dev->parent);
+ struct kempld_platform_data *pdata = pld->dev->platform_data;
+ struct kempld_gpio_data *gpio;
+ struct gpio_chip *chip;
+ int ret;
+
+ if (pld->info.spec_major < 2) {
+ dev_err(dev,
+ "Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");
+ return -ENODEV;
+ }
+
+ gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
+ if (gpio == NULL)
+ return -ENOMEM;
+
+ gpio->pld = pld;
+
+ platform_set_drvdata(pdev, gpio);
+
+ chip = &gpio->chip;
+ chip->label = "gpio-kempld";
+ chip->owner = THIS_MODULE;
+ chip->dev = dev;
+ chip->can_sleep = 1;
+ if (pdata && pdata->gpio_base)
+ chip->base = pdata->gpio_base;
+ else
+ chip->base = -1;
+ chip->direction_input = kempld_gpio_direction_input;
+ chip->direction_output = kempld_gpio_direction_output;
+ chip->get_direction = kempld_gpio_get_direction;
+ chip->get = kempld_gpio_get;
+ chip->set = kempld_gpio_set;
+ chip->ngpio = kempld_gpio_pincount(pld);
+ if (chip->ngpio == 0) {
+ dev_err(dev, "No GPIO pins detected\n");
+ return -ENODEV;
+ }
+
+ ret = gpiochip_add(chip);
+ if (ret) {
+ dev_err(dev, "Could not register GPIO chip\n");
+ return ret;
+ }
+
+ dev_info(dev, "GPIO functionality initialized with %d pins\n",
+ chip->ngpio);
+
+ return 0;
+}
+
+static int kempld_gpio_remove(struct platform_device *pdev)
+{
+ struct kempld_gpio_data *gpio = platform_get_drvdata(pdev);
+
+ return gpiochip_remove(&gpio->chip);
+}
+
+static struct platform_driver kempld_gpio_driver = {
+ .driver = {
+ .name = "gpio-kempld",
+ .owner = THIS_MODULE,
+ },
+ .probe = kempld_gpio_probe,
+ .remove = kempld_gpio_remove,
+};
+
+module_platform_driver(kempld_gpio_driver);
+
+MODULE_DESCRIPTION("KEM PLD GPIO Driver");
+MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:gpio-kempld");