131 lines
3.4 KiB
C
131 lines
3.4 KiB
C
/*
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* Driver for GE FPGA based GPIO
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*
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* Author: Martyn Welch <martyn.welch@ge.com>
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*
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* 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
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*
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* This file is licensed under the terms of the GNU General Public License
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* version 2. This program is licensed "as is" without any warranty of any
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* kind, whether express or implied.
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*/
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/* TODO
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*
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* Configuration of output modes (totem-pole/open-drain)
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* Interrupt configuration - interrupts are always generated the FPGA relies on
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* the I/O interrupt controllers mask to stop them propergating
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*/
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#include <linux/kernel.h>
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#include <linux/io.h>
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#include <linux/of_device.h>
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#include <linux/of_gpio.h>
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#include <linux/module.h>
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#define GEF_GPIO_DIRECT 0x00
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#define GEF_GPIO_IN 0x04
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#define GEF_GPIO_OUT 0x08
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#define GEF_GPIO_TRIG 0x0C
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#define GEF_GPIO_POLAR_A 0x10
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#define GEF_GPIO_POLAR_B 0x14
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#define GEF_GPIO_INT_STAT 0x18
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#define GEF_GPIO_OVERRUN 0x1C
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#define GEF_GPIO_MODE 0x20
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static void gef_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
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{
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struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
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unsigned int data;
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data = ioread32be(mmchip->regs + GEF_GPIO_OUT);
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if (value)
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data = data | BIT(offset);
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else
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data = data & ~BIT(offset);
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iowrite32be(data, mmchip->regs + GEF_GPIO_OUT);
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}
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static int gef_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
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{
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unsigned int data;
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struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
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data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT);
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data = data | BIT(offset);
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iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT);
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return 0;
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}
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static int gef_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int value)
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{
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unsigned int data;
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struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
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/* Set value before switching to output */
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gef_gpio_set(mmchip->regs + GEF_GPIO_OUT, offset, value);
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data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT);
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data = data & ~BIT(offset);
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iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT);
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return 0;
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}
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static int gef_gpio_get(struct gpio_chip *chip, unsigned offset)
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{
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struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
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return !!(ioread32be(mmchip->regs + GEF_GPIO_IN) & BIT(offset));
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}
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static const struct of_device_id gef_gpio_ids[] = {
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{
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.compatible = "gef,sbc610-gpio",
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.data = (void *)19,
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}, {
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.compatible = "gef,sbc310-gpio",
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.data = (void *)6,
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}, {
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.compatible = "ge,imp3a-gpio",
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.data = (void *)16,
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},
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{ }
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};
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MODULE_DEVICE_TABLE(of, gef_gpio_ids);
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static int __init gef_gpio_probe(struct platform_device *pdev)
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{
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const struct of_device_id *of_id =
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of_match_device(gef_gpio_ids, &pdev->dev);
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struct of_mm_gpio_chip *mmchip;
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mmchip = devm_kzalloc(&pdev->dev, sizeof(*mmchip), GFP_KERNEL);
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if (!mmchip)
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return -ENOMEM;
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/* Setup pointers to chip functions */
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mmchip->gc.ngpio = (u16)(uintptr_t)of_id->data;
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mmchip->gc.of_gpio_n_cells = 2;
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mmchip->gc.direction_input = gef_gpio_dir_in;
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mmchip->gc.direction_output = gef_gpio_dir_out;
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mmchip->gc.get = gef_gpio_get;
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mmchip->gc.set = gef_gpio_set;
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/* This function adds a memory mapped GPIO chip */
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return of_mm_gpiochip_add(pdev->dev.of_node, mmchip);
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};
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static struct platform_driver gef_gpio_driver = {
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.driver = {
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.name = "gef-gpio",
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.of_match_table = gef_gpio_ids,
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},
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};
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module_platform_driver_probe(gef_gpio_driver, gef_gpio_probe);
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MODULE_DESCRIPTION("GE I/O FPGA GPIO driver");
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MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com");
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MODULE_LICENSE("GPL");
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