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- /*
- * Janz MODULbus VMOD-TTL GPIO Driver
- *
- * Copyright (c) 2010 Ira W. Snyder <iws@ovro.caltech.edu>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 of the License, or (at your
- * option) any later version.
- */
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/init.h>
- #include <linux/interrupt.h>
- #include <linux/delay.h>
- #include <linux/platform_device.h>
- #include <linux/io.h>
- #include <linux/gpio.h>
- #include <linux/slab.h>
- #include <linux/mfd/janz.h>
- #define DRV_NAME "janz-ttl"
- #define PORTA_DIRECTION 0x23
- #define PORTB_DIRECTION 0x2B
- #define PORTC_DIRECTION 0x06
- #define PORTA_IOCTL 0x24
- #define PORTB_IOCTL 0x2C
- #define PORTC_IOCTL 0x07
- #define MASTER_INT_CTL 0x00
- #define MASTER_CONF_CTL 0x01
- #define CONF_PAE (1 << 2)
- #define CONF_PBE (1 << 7)
- #define CONF_PCE (1 << 4)
- struct ttl_control_regs {
- __be16 portc;
- __be16 portb;
- __be16 porta;
- __be16 control;
- };
- struct ttl_module {
- struct gpio_chip gpio;
- /* base address of registers */
- struct ttl_control_regs __iomem *regs;
- u8 portc_shadow;
- u8 portb_shadow;
- u8 porta_shadow;
- spinlock_t lock;
- };
- static int ttl_get_value(struct gpio_chip *gpio, unsigned offset)
- {
- struct ttl_module *mod = dev_get_drvdata(gpio->parent);
- u8 *shadow;
- int ret;
- if (offset < 8) {
- shadow = &mod->porta_shadow;
- } else if (offset < 16) {
- shadow = &mod->portb_shadow;
- offset -= 8;
- } else {
- shadow = &mod->portc_shadow;
- offset -= 16;
- }
- spin_lock(&mod->lock);
- ret = *shadow & (1 << offset);
- spin_unlock(&mod->lock);
- return !!ret;
- }
- static void ttl_set_value(struct gpio_chip *gpio, unsigned offset, int value)
- {
- struct ttl_module *mod = dev_get_drvdata(gpio->parent);
- void __iomem *port;
- u8 *shadow;
- if (offset < 8) {
- port = &mod->regs->porta;
- shadow = &mod->porta_shadow;
- } else if (offset < 16) {
- port = &mod->regs->portb;
- shadow = &mod->portb_shadow;
- offset -= 8;
- } else {
- port = &mod->regs->portc;
- shadow = &mod->portc_shadow;
- offset -= 16;
- }
- spin_lock(&mod->lock);
- if (value)
- *shadow |= (1 << offset);
- else
- *shadow &= ~(1 << offset);
- iowrite16be(*shadow, port);
- spin_unlock(&mod->lock);
- }
- static void ttl_write_reg(struct ttl_module *mod, u8 reg, u16 val)
- {
- iowrite16be(reg, &mod->regs->control);
- iowrite16be(val, &mod->regs->control);
- }
- static void ttl_setup_device(struct ttl_module *mod)
- {
- /* reset the device to a known state */
- iowrite16be(0x0000, &mod->regs->control);
- iowrite16be(0x0001, &mod->regs->control);
- iowrite16be(0x0000, &mod->regs->control);
- /* put all ports in open-drain mode */
- ttl_write_reg(mod, PORTA_IOCTL, 0x00ff);
- ttl_write_reg(mod, PORTB_IOCTL, 0x00ff);
- ttl_write_reg(mod, PORTC_IOCTL, 0x000f);
- /* set all ports as outputs */
- ttl_write_reg(mod, PORTA_DIRECTION, 0x0000);
- ttl_write_reg(mod, PORTB_DIRECTION, 0x0000);
- ttl_write_reg(mod, PORTC_DIRECTION, 0x0000);
- /* set all ports to drive zeroes */
- iowrite16be(0x0000, &mod->regs->porta);
- iowrite16be(0x0000, &mod->regs->portb);
- iowrite16be(0x0000, &mod->regs->portc);
- /* enable all ports */
- ttl_write_reg(mod, MASTER_CONF_CTL, CONF_PAE | CONF_PBE | CONF_PCE);
- }
- static int ttl_probe(struct platform_device *pdev)
- {
- struct janz_platform_data *pdata;
- struct device *dev = &pdev->dev;
- struct ttl_module *mod;
- struct gpio_chip *gpio;
- struct resource *res;
- int ret;
- pdata = dev_get_platdata(&pdev->dev);
- if (!pdata) {
- dev_err(dev, "no platform data\n");
- return -ENXIO;
- }
- mod = devm_kzalloc(dev, sizeof(*mod), GFP_KERNEL);
- if (!mod)
- return -ENOMEM;
- platform_set_drvdata(pdev, mod);
- spin_lock_init(&mod->lock);
- /* get access to the MODULbus registers for this module */
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- mod->regs = devm_ioremap_resource(dev, res);
- if (IS_ERR(mod->regs))
- return PTR_ERR(mod->regs);
- ttl_setup_device(mod);
- /* Initialize the GPIO data structures */
- gpio = &mod->gpio;
- gpio->parent = &pdev->dev;
- gpio->label = pdev->name;
- gpio->get = ttl_get_value;
- gpio->set = ttl_set_value;
- gpio->owner = THIS_MODULE;
- /* request dynamic allocation */
- gpio->base = -1;
- gpio->ngpio = 20;
- ret = devm_gpiochip_add_data(dev, gpio, NULL);
- if (ret) {
- dev_err(dev, "unable to add GPIO chip\n");
- return ret;
- }
- return 0;
- }
- static struct platform_driver ttl_driver = {
- .driver = {
- .name = DRV_NAME,
- },
- .probe = ttl_probe,
- };
- module_platform_driver(ttl_driver);
- MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
- MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver");
- MODULE_LICENSE("GPL");
- MODULE_ALIAS("platform:janz-ttl");
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