diff options
Diffstat (limited to 'arch/mips/lantiq/xway/gpio_ebu.c')
| -rw-r--r-- | arch/mips/lantiq/xway/gpio_ebu.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/arch/mips/lantiq/xway/gpio_ebu.c b/arch/mips/lantiq/xway/gpio_ebu.c new file mode 100644 index 000000000000..a479355abdb9 --- /dev/null +++ b/arch/mips/lantiq/xway/gpio_ebu.c @@ -0,0 +1,126 @@ +/* + * 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) 2010 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/io.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 */ + +/* we keep a shadow value of the last value written to the ebu */ +static int ltq_ebu_gpio_shadow = 0x0; +static void __iomem *ltq_ebu_gpio_membase; + +static void ltq_ebu_apply(void) +{ + unsigned long flags; + + spin_lock_irqsave(&ebu_lock, flags); + ltq_ebu_w32(LTQ_EBU_BUSCON, LTQ_EBU_BUSCON1); + *((__u16 *)ltq_ebu_gpio_membase) = ltq_ebu_gpio_shadow; + ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1); + spin_unlock_irqrestore(&ebu_lock, flags); +} + +static void ltq_ebu_set(struct gpio_chip *chip, unsigned offset, int value) +{ + if (value) + ltq_ebu_gpio_shadow |= (1 << offset); + else + ltq_ebu_gpio_shadow &= ~(1 << offset); + ltq_ebu_apply(); +} + +static int ltq_ebu_direction_output(struct gpio_chip *chip, unsigned offset, + int value) +{ + ltq_ebu_set(chip, offset, value); + + return 0; +} + +static struct gpio_chip ltq_ebu_chip = { + .label = "ltq_ebu", + .direction_output = ltq_ebu_direction_output, + .set = ltq_ebu_set, + .base = 72, + .ngpio = 16, + .can_sleep = 1, + .owner = THIS_MODULE, +}; + +static int ltq_ebu_probe(struct platform_device *pdev) +{ + int ret = 0; + struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + if (!res) { + dev_err(&pdev->dev, "failed to get memory resource\n"); + return -ENOENT; + } + + res = devm_request_mem_region(&pdev->dev, res->start, + resource_size(res), dev_name(&pdev->dev)); + if (!res) { + dev_err(&pdev->dev, "failed to request memory resource\n"); + return -EBUSY; + } + + ltq_ebu_gpio_membase = devm_ioremap_nocache(&pdev->dev, res->start, + resource_size(res)); + if (!ltq_ebu_gpio_membase) { + dev_err(&pdev->dev, "Failed to ioremap mem region\n"); + return -ENOMEM; + } + + /* grab the default shadow value passed form the platform code */ + ltq_ebu_gpio_shadow = (unsigned int) pdev->dev.platform_data; + + /* tell the ebu controller which memory address we will be using */ + ltq_ebu_w32(pdev->resource->start | 0x1, LTQ_EBU_ADDRSEL1); + + /* write protect the region */ + ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1); + + ret = gpiochip_add(<q_ebu_chip); + if (!ret) + ltq_ebu_apply(); + return ret; +} + +static struct platform_driver ltq_ebu_driver = { + .probe = ltq_ebu_probe, + .driver = { + .name = "ltq_ebu", + .owner = THIS_MODULE, + }, +}; + +static int __init ltq_ebu_init(void) +{ + int ret = platform_driver_register(<q_ebu_driver); + + if (ret) + pr_info("ltq_ebu : Error registering platfom driver!"); + return ret; +} + +postcore_initcall(ltq_ebu_init); |