/* * 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 <john@phrozen.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);