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1// SPDX-License-Identifier: GPL-2.0-only2/*3 *4 * Copyright (C) 2012 John Crispin <john@phrozen.org>5 */6 7#include <linux/init.h>8#include <linux/module.h>9#include <linux/types.h>10#include <linux/platform_device.h>11#include <linux/mutex.h>12#include <linux/gpio/driver.h>13#include <linux/gpio/legacy-of-mm-gpiochip.h>14#include <linux/of.h>15#include <linux/io.h>16#include <linux/slab.h>17 18#include <lantiq_soc.h>19 20/*21 * By attaching hardware latches to the EBU it is possible to create output22 * only gpios. This driver configures a special memory address, which when23 * written to outputs 16 bit to the latches.24 */25 26#define LTQ_EBU_BUSCON 0x1e7ff /* 16 bit access, slowest timing */27#define LTQ_EBU_WP 0x80000000 /* write protect bit */28 29struct ltq_mm {30 struct of_mm_gpio_chip mmchip;31 u16 shadow; /* shadow the latches state */32};33 34/**35 * ltq_mm_apply() - write the shadow value to the ebu address.36 * @chip: Pointer to our private data structure.37 *38 * Write the shadow value to the EBU to set the gpios. We need to set the39 * global EBU lock to make sure that PCI/MTD don't break.40 */41static void ltq_mm_apply(struct ltq_mm *chip)42{43 unsigned long flags;44 45 spin_lock_irqsave(&ebu_lock, flags);46 ltq_ebu_w32(LTQ_EBU_BUSCON, LTQ_EBU_BUSCON1);47 __raw_writew(chip->shadow, chip->mmchip.regs);48 ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1);49 spin_unlock_irqrestore(&ebu_lock, flags);50}51 52/**53 * ltq_mm_set() - gpio_chip->set - set gpios.54 * @gc: Pointer to gpio_chip device structure.55 * @gpio: GPIO signal number.56 * @val: Value to be written to specified signal.57 *58 * Set the shadow value and call ltq_mm_apply.59 */60static void ltq_mm_set(struct gpio_chip *gc, unsigned offset, int value)61{62 struct ltq_mm *chip = gpiochip_get_data(gc);63 64 if (value)65 chip->shadow |= (1 << offset);66 else67 chip->shadow &= ~(1 << offset);68 ltq_mm_apply(chip);69}70 71/**72 * ltq_mm_dir_out() - gpio_chip->dir_out - set gpio direction.73 * @gc: Pointer to gpio_chip device structure.74 * @gpio: GPIO signal number.75 * @val: Value to be written to specified signal.76 *77 * Same as ltq_mm_set, always returns 0.78 */79static int ltq_mm_dir_out(struct gpio_chip *gc, unsigned offset, int value)80{81 ltq_mm_set(gc, offset, value);82 83 return 0;84}85 86/**87 * ltq_mm_save_regs() - Set initial values of GPIO pins88 * @mm_gc: pointer to memory mapped GPIO chip structure89 */90static void ltq_mm_save_regs(struct of_mm_gpio_chip *mm_gc)91{92 struct ltq_mm *chip =93 container_of(mm_gc, struct ltq_mm, mmchip);94 95 /* tell the ebu controller which memory address we will be using */96 ltq_ebu_w32(CPHYSADDR(chip->mmchip.regs) | 0x1, LTQ_EBU_ADDRSEL1);97 98 ltq_mm_apply(chip);99}100 101static int ltq_mm_probe(struct platform_device *pdev)102{103 struct ltq_mm *chip;104 u32 shadow;105 106 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);107 if (!chip)108 return -ENOMEM;109 110 platform_set_drvdata(pdev, chip);111 112 chip->mmchip.gc.ngpio = 16;113 chip->mmchip.gc.direction_output = ltq_mm_dir_out;114 chip->mmchip.gc.set = ltq_mm_set;115 chip->mmchip.save_regs = ltq_mm_save_regs;116 117 /* store the shadow value if one was passed by the devicetree */118 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,shadow", &shadow))119 chip->shadow = shadow;120 121 return of_mm_gpiochip_add_data(pdev->dev.of_node, &chip->mmchip, chip);122}123 124static void ltq_mm_remove(struct platform_device *pdev)125{126 struct ltq_mm *chip = platform_get_drvdata(pdev);127 128 of_mm_gpiochip_remove(&chip->mmchip);129}130 131static const struct of_device_id ltq_mm_match[] = {132 { .compatible = "lantiq,gpio-mm" },133 {},134};135MODULE_DEVICE_TABLE(of, ltq_mm_match);136 137static struct platform_driver ltq_mm_driver = {138 .probe = ltq_mm_probe,139 .remove_new = ltq_mm_remove,140 .driver = {141 .name = "gpio-mm-ltq",142 .of_match_table = ltq_mm_match,143 },144};145 146static int __init ltq_mm_init(void)147{148 return platform_driver_register(<q_mm_driver);149}150 151subsys_initcall(ltq_mm_init);152 153static void __exit ltq_mm_exit(void)154{155 platform_driver_unregister(<q_mm_driver);156}157module_exit(ltq_mm_exit);158