1*5238f7bcSJohn Crispin /* 2*5238f7bcSJohn Crispin * This program is free software; you can redistribute it and/or modify it 3*5238f7bcSJohn Crispin * under the terms of the GNU General Public License version 2 as published 4*5238f7bcSJohn Crispin * by the Free Software Foundation. 5*5238f7bcSJohn Crispin * 6*5238f7bcSJohn Crispin * Copyright (C) 2010 John Crispin <blogic@openwrt.org> 7*5238f7bcSJohn Crispin */ 8*5238f7bcSJohn Crispin 9*5238f7bcSJohn Crispin #include <linux/init.h> 10*5238f7bcSJohn Crispin #include <linux/export.h> 11*5238f7bcSJohn Crispin #include <linux/types.h> 12*5238f7bcSJohn Crispin #include <linux/platform_device.h> 13*5238f7bcSJohn Crispin #include <linux/mutex.h> 14*5238f7bcSJohn Crispin #include <linux/gpio.h> 15*5238f7bcSJohn Crispin #include <linux/io.h> 16*5238f7bcSJohn Crispin 17*5238f7bcSJohn Crispin #include <lantiq_soc.h> 18*5238f7bcSJohn Crispin 19*5238f7bcSJohn Crispin /* 20*5238f7bcSJohn Crispin * By attaching hardware latches to the EBU it is possible to create output 21*5238f7bcSJohn Crispin * only gpios. This driver configures a special memory address, which when 22*5238f7bcSJohn Crispin * written to outputs 16 bit to the latches. 23*5238f7bcSJohn Crispin */ 24*5238f7bcSJohn Crispin 25*5238f7bcSJohn Crispin #define LTQ_EBU_BUSCON 0x1e7ff /* 16 bit access, slowest timing */ 26*5238f7bcSJohn Crispin #define LTQ_EBU_WP 0x80000000 /* write protect bit */ 27*5238f7bcSJohn Crispin 28*5238f7bcSJohn Crispin /* we keep a shadow value of the last value written to the ebu */ 29*5238f7bcSJohn Crispin static int ltq_ebu_gpio_shadow = 0x0; 30*5238f7bcSJohn Crispin static void __iomem *ltq_ebu_gpio_membase; 31*5238f7bcSJohn Crispin 32*5238f7bcSJohn Crispin static void ltq_ebu_apply(void) 33*5238f7bcSJohn Crispin { 34*5238f7bcSJohn Crispin unsigned long flags; 35*5238f7bcSJohn Crispin 36*5238f7bcSJohn Crispin spin_lock_irqsave(&ebu_lock, flags); 37*5238f7bcSJohn Crispin ltq_ebu_w32(LTQ_EBU_BUSCON, LTQ_EBU_BUSCON1); 38*5238f7bcSJohn Crispin *((__u16 *)ltq_ebu_gpio_membase) = ltq_ebu_gpio_shadow; 39*5238f7bcSJohn Crispin ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1); 40*5238f7bcSJohn Crispin spin_unlock_irqrestore(&ebu_lock, flags); 41*5238f7bcSJohn Crispin } 42*5238f7bcSJohn Crispin 43*5238f7bcSJohn Crispin static void ltq_ebu_set(struct gpio_chip *chip, unsigned offset, int value) 44*5238f7bcSJohn Crispin { 45*5238f7bcSJohn Crispin if (value) 46*5238f7bcSJohn Crispin ltq_ebu_gpio_shadow |= (1 << offset); 47*5238f7bcSJohn Crispin else 48*5238f7bcSJohn Crispin ltq_ebu_gpio_shadow &= ~(1 << offset); 49*5238f7bcSJohn Crispin ltq_ebu_apply(); 50*5238f7bcSJohn Crispin } 51*5238f7bcSJohn Crispin 52*5238f7bcSJohn Crispin static int ltq_ebu_direction_output(struct gpio_chip *chip, unsigned offset, 53*5238f7bcSJohn Crispin int value) 54*5238f7bcSJohn Crispin { 55*5238f7bcSJohn Crispin ltq_ebu_set(chip, offset, value); 56*5238f7bcSJohn Crispin 57*5238f7bcSJohn Crispin return 0; 58*5238f7bcSJohn Crispin } 59*5238f7bcSJohn Crispin 60*5238f7bcSJohn Crispin static struct gpio_chip ltq_ebu_chip = { 61*5238f7bcSJohn Crispin .label = "ltq_ebu", 62*5238f7bcSJohn Crispin .direction_output = ltq_ebu_direction_output, 63*5238f7bcSJohn Crispin .set = ltq_ebu_set, 64*5238f7bcSJohn Crispin .base = 72, 65*5238f7bcSJohn Crispin .ngpio = 16, 66*5238f7bcSJohn Crispin .can_sleep = 1, 67*5238f7bcSJohn Crispin .owner = THIS_MODULE, 68*5238f7bcSJohn Crispin }; 69*5238f7bcSJohn Crispin 70*5238f7bcSJohn Crispin static int ltq_ebu_probe(struct platform_device *pdev) 71*5238f7bcSJohn Crispin { 72*5238f7bcSJohn Crispin int ret = 0; 73*5238f7bcSJohn Crispin struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 74*5238f7bcSJohn Crispin 75*5238f7bcSJohn Crispin if (!res) { 76*5238f7bcSJohn Crispin dev_err(&pdev->dev, "failed to get memory resource\n"); 77*5238f7bcSJohn Crispin return -ENOENT; 78*5238f7bcSJohn Crispin } 79*5238f7bcSJohn Crispin 80*5238f7bcSJohn Crispin res = devm_request_mem_region(&pdev->dev, res->start, 81*5238f7bcSJohn Crispin resource_size(res), dev_name(&pdev->dev)); 82*5238f7bcSJohn Crispin if (!res) { 83*5238f7bcSJohn Crispin dev_err(&pdev->dev, "failed to request memory resource\n"); 84*5238f7bcSJohn Crispin return -EBUSY; 85*5238f7bcSJohn Crispin } 86*5238f7bcSJohn Crispin 87*5238f7bcSJohn Crispin ltq_ebu_gpio_membase = devm_ioremap_nocache(&pdev->dev, res->start, 88*5238f7bcSJohn Crispin resource_size(res)); 89*5238f7bcSJohn Crispin if (!ltq_ebu_gpio_membase) { 90*5238f7bcSJohn Crispin dev_err(&pdev->dev, "Failed to ioremap mem region\n"); 91*5238f7bcSJohn Crispin return -ENOMEM; 92*5238f7bcSJohn Crispin } 93*5238f7bcSJohn Crispin 94*5238f7bcSJohn Crispin /* grab the default shadow value passed form the platform code */ 95*5238f7bcSJohn Crispin ltq_ebu_gpio_shadow = (unsigned int) pdev->dev.platform_data; 96*5238f7bcSJohn Crispin 97*5238f7bcSJohn Crispin /* tell the ebu controller which memory address we will be using */ 98*5238f7bcSJohn Crispin ltq_ebu_w32(pdev->resource->start | 0x1, LTQ_EBU_ADDRSEL1); 99*5238f7bcSJohn Crispin 100*5238f7bcSJohn Crispin /* write protect the region */ 101*5238f7bcSJohn Crispin ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1); 102*5238f7bcSJohn Crispin 103*5238f7bcSJohn Crispin ret = gpiochip_add(<q_ebu_chip); 104*5238f7bcSJohn Crispin if (!ret) 105*5238f7bcSJohn Crispin ltq_ebu_apply(); 106*5238f7bcSJohn Crispin return ret; 107*5238f7bcSJohn Crispin } 108*5238f7bcSJohn Crispin 109*5238f7bcSJohn Crispin static struct platform_driver ltq_ebu_driver = { 110*5238f7bcSJohn Crispin .probe = ltq_ebu_probe, 111*5238f7bcSJohn Crispin .driver = { 112*5238f7bcSJohn Crispin .name = "ltq_ebu", 113*5238f7bcSJohn Crispin .owner = THIS_MODULE, 114*5238f7bcSJohn Crispin }, 115*5238f7bcSJohn Crispin }; 116*5238f7bcSJohn Crispin 117*5238f7bcSJohn Crispin static int __init ltq_ebu_init(void) 118*5238f7bcSJohn Crispin { 119*5238f7bcSJohn Crispin int ret = platform_driver_register(<q_ebu_driver); 120*5238f7bcSJohn Crispin 121*5238f7bcSJohn Crispin if (ret) 122*5238f7bcSJohn Crispin pr_info("ltq_ebu : Error registering platfom driver!"); 123*5238f7bcSJohn Crispin return ret; 124*5238f7bcSJohn Crispin } 125*5238f7bcSJohn Crispin 126*5238f7bcSJohn Crispin postcore_initcall(ltq_ebu_init); 127