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- /*
- * 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.
- *
- * Copyright (C) 2012 John Crispin <blogic@openwrt.org>
- */
- #include <linux/init.h>
- #include <linux/module.h>
- #include <linux/types.h>
- #include <linux/platform_device.h>
- #include <linux/mutex.h>
- #include <linux/gpio.h>
- #include <linux/of.h>
- #include <linux/of_gpio.h>
- #include <linux/io.h>
- #include <linux/slab.h>
- #include <lantiq_soc.h>
- /*
- * By attaching hardware latches to the EBU it is possible to create output
- * only gpios. This driver configures a special memory address, which when
- * written to outputs 16 bit to the latches.
- */
- #define LTQ_EBU_BUSCON 0x1e7ff /* 16 bit access, slowest timing */
- #define LTQ_EBU_WP 0x80000000 /* write protect bit */
- struct ltq_mm {
- struct of_mm_gpio_chip mmchip;
- u16 shadow; /* shadow the latches state */
- };
- /**
- * ltq_mm_apply() - write the shadow value to the ebu address.
- * @chip: Pointer to our private data structure.
- *
- * Write the shadow value to the EBU to set the gpios. We need to set the
- * global EBU lock to make sure that PCI/MTD dont break.
- */
- static void ltq_mm_apply(struct ltq_mm *chip)
- {
- unsigned long flags;
- spin_lock_irqsave(&ebu_lock, flags);
- ltq_ebu_w32(LTQ_EBU_BUSCON, LTQ_EBU_BUSCON1);
- __raw_writew(chip->shadow, chip->mmchip.regs);
- ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1);
- spin_unlock_irqrestore(&ebu_lock, flags);
- }
- /**
- * ltq_mm_set() - gpio_chip->set - set gpios.
- * @gc: Pointer to gpio_chip device structure.
- * @gpio: GPIO signal number.
- * @val: Value to be written to specified signal.
- *
- * Set the shadow value and call ltq_mm_apply.
- */
- static void ltq_mm_set(struct gpio_chip *gc, unsigned offset, int value)
- {
- struct ltq_mm *chip = gpiochip_get_data(gc);
- if (value)
- chip->shadow |= (1 << offset);
- else
- chip->shadow &= ~(1 << offset);
- ltq_mm_apply(chip);
- }
- /**
- * ltq_mm_dir_out() - gpio_chip->dir_out - set gpio direction.
- * @gc: Pointer to gpio_chip device structure.
- * @gpio: GPIO signal number.
- * @val: Value to be written to specified signal.
- *
- * Same as ltq_mm_set, always returns 0.
- */
- static int ltq_mm_dir_out(struct gpio_chip *gc, unsigned offset, int value)
- {
- ltq_mm_set(gc, offset, value);
- return 0;
- }
- /**
- * ltq_mm_save_regs() - Set initial values of GPIO pins
- * @mm_gc: pointer to memory mapped GPIO chip structure
- */
- static void ltq_mm_save_regs(struct of_mm_gpio_chip *mm_gc)
- {
- struct ltq_mm *chip =
- container_of(mm_gc, struct ltq_mm, mmchip);
- /* tell the ebu controller which memory address we will be using */
- ltq_ebu_w32(CPHYSADDR(chip->mmchip.regs) | 0x1, LTQ_EBU_ADDRSEL1);
- ltq_mm_apply(chip);
- }
- static int ltq_mm_probe(struct platform_device *pdev)
- {
- struct ltq_mm *chip;
- u32 shadow;
- chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
- if (!chip)
- return -ENOMEM;
- platform_set_drvdata(pdev, chip);
- chip->mmchip.gc.ngpio = 16;
- chip->mmchip.gc.direction_output = ltq_mm_dir_out;
- chip->mmchip.gc.set = ltq_mm_set;
- chip->mmchip.save_regs = ltq_mm_save_regs;
- /* store the shadow value if one was passed by the devicetree */
- if (!of_property_read_u32(pdev->dev.of_node, "lantiq,shadow", &shadow))
- chip->shadow = shadow;
- return of_mm_gpiochip_add_data(pdev->dev.of_node, &chip->mmchip, chip);
- }
- static int ltq_mm_remove(struct platform_device *pdev)
- {
- struct ltq_mm *chip = platform_get_drvdata(pdev);
- of_mm_gpiochip_remove(&chip->mmchip);
- return 0;
- }
- static const struct of_device_id ltq_mm_match[] = {
- { .compatible = "lantiq,gpio-mm" },
- {},
- };
- MODULE_DEVICE_TABLE(of, ltq_mm_match);
- static struct platform_driver ltq_mm_driver = {
- .probe = ltq_mm_probe,
- .remove = ltq_mm_remove,
- .driver = {
- .name = "gpio-mm-ltq",
- .of_match_table = ltq_mm_match,
- },
- };
- static int __init ltq_mm_init(void)
- {
- return platform_driver_register(<q_mm_driver);
- }
- subsys_initcall(ltq_mm_init);
- static void __exit ltq_mm_exit(void)
- {
- platform_driver_unregister(<q_mm_driver);
- }
- module_exit(ltq_mm_exit);
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