// SPDX-License-Identifier: GPL-2.0-or-later /* * Janz MODULbus VMOD-TTL GPIO Driver * * Copyright (c) 2010 Ira W. Snyder <iws@ovro.caltech.edu> */ #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/driver.h> #include <linux/slab.h> #include <linux/bitops.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 BIT(2) #define CONF_PBE BIT(7) #define CONF_PCE BIT(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 & BIT(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 |= BIT(offset); else *shadow &= ~BIT(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 ttl_module *mod; struct gpio_chip *gpio; int ret; pdata = dev_get_platdata(&pdev->dev); if (!pdata) { dev_err(&pdev->dev, "no platform data\n"); return -ENXIO; } mod = devm_kzalloc(&pdev->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 */ mod->regs = devm_platform_ioremap_resource(pdev, 0); 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(&pdev->dev, gpio, NULL); if (ret) { dev_err(&pdev->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");