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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 | // 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"); |