linux/drivers/gpio/gpio-ftgpio010.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Faraday Technolog FTGPIO010 gpiochip and interrupt routines
   4 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
   5 *
   6 * Based on arch/arm/mach-gemini/gpio.c:
   7 * Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
   8 *
   9 * Based on plat-mxc/gpio.c:
  10 * MXC GPIO support. (c) 2008 Daniel Mack <daniel@caiaq.de>
  11 * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
  12 */
  13#include <linux/gpio/driver.h>
  14#include <linux/io.h>
  15#include <linux/interrupt.h>
  16#include <linux/platform_device.h>
  17#include <linux/bitops.h>
  18#include <linux/clk.h>
  19
  20/* GPIO registers definition */
  21#define GPIO_DATA_OUT           0x00
  22#define GPIO_DATA_IN            0x04
  23#define GPIO_DIR                0x08
  24#define GPIO_BYPASS_IN          0x0C
  25#define GPIO_DATA_SET           0x10
  26#define GPIO_DATA_CLR           0x14
  27#define GPIO_PULL_EN            0x18
  28#define GPIO_PULL_TYPE          0x1C
  29#define GPIO_INT_EN             0x20
  30#define GPIO_INT_STAT_RAW       0x24
  31#define GPIO_INT_STAT_MASKED    0x28
  32#define GPIO_INT_MASK           0x2C
  33#define GPIO_INT_CLR            0x30
  34#define GPIO_INT_TYPE           0x34
  35#define GPIO_INT_BOTH_EDGE      0x38
  36#define GPIO_INT_LEVEL          0x3C
  37#define GPIO_DEBOUNCE_EN        0x40
  38#define GPIO_DEBOUNCE_PRESCALE  0x44
  39
  40/**
  41 * struct ftgpio_gpio - Gemini GPIO state container
  42 * @dev: containing device for this instance
  43 * @gc: gpiochip for this instance
  44 * @irq: irqchip for this instance
  45 * @base: remapped I/O-memory base
  46 * @clk: silicon clock
  47 */
  48struct ftgpio_gpio {
  49        struct device *dev;
  50        struct gpio_chip gc;
  51        struct irq_chip irq;
  52        void __iomem *base;
  53        struct clk *clk;
  54};
  55
  56static void ftgpio_gpio_ack_irq(struct irq_data *d)
  57{
  58        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
  59        struct ftgpio_gpio *g = gpiochip_get_data(gc);
  60
  61        writel(BIT(irqd_to_hwirq(d)), g->base + GPIO_INT_CLR);
  62}
  63
  64static void ftgpio_gpio_mask_irq(struct irq_data *d)
  65{
  66        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
  67        struct ftgpio_gpio *g = gpiochip_get_data(gc);
  68        u32 val;
  69
  70        val = readl(g->base + GPIO_INT_EN);
  71        val &= ~BIT(irqd_to_hwirq(d));
  72        writel(val, g->base + GPIO_INT_EN);
  73}
  74
  75static void ftgpio_gpio_unmask_irq(struct irq_data *d)
  76{
  77        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
  78        struct ftgpio_gpio *g = gpiochip_get_data(gc);
  79        u32 val;
  80
  81        val = readl(g->base + GPIO_INT_EN);
  82        val |= BIT(irqd_to_hwirq(d));
  83        writel(val, g->base + GPIO_INT_EN);
  84}
  85
  86static int ftgpio_gpio_set_irq_type(struct irq_data *d, unsigned int type)
  87{
  88        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
  89        struct ftgpio_gpio *g = gpiochip_get_data(gc);
  90        u32 mask = BIT(irqd_to_hwirq(d));
  91        u32 reg_both, reg_level, reg_type;
  92
  93        reg_type = readl(g->base + GPIO_INT_TYPE);
  94        reg_level = readl(g->base + GPIO_INT_LEVEL);
  95        reg_both = readl(g->base + GPIO_INT_BOTH_EDGE);
  96
  97        switch (type) {
  98        case IRQ_TYPE_EDGE_BOTH:
  99                irq_set_handler_locked(d, handle_edge_irq);
 100                reg_type &= ~mask;
 101                reg_both |= mask;
 102                break;
 103        case IRQ_TYPE_EDGE_RISING:
 104                irq_set_handler_locked(d, handle_edge_irq);
 105                reg_type &= ~mask;
 106                reg_both &= ~mask;
 107                reg_level &= ~mask;
 108                break;
 109        case IRQ_TYPE_EDGE_FALLING:
 110                irq_set_handler_locked(d, handle_edge_irq);
 111                reg_type &= ~mask;
 112                reg_both &= ~mask;
 113                reg_level |= mask;
 114                break;
 115        case IRQ_TYPE_LEVEL_HIGH:
 116                irq_set_handler_locked(d, handle_level_irq);
 117                reg_type |= mask;
 118                reg_level &= ~mask;
 119                break;
 120        case IRQ_TYPE_LEVEL_LOW:
 121                irq_set_handler_locked(d, handle_level_irq);
 122                reg_type |= mask;
 123                reg_level |= mask;
 124                break;
 125        default:
 126                irq_set_handler_locked(d, handle_bad_irq);
 127                return -EINVAL;
 128        }
 129
 130        writel(reg_type, g->base + GPIO_INT_TYPE);
 131        writel(reg_level, g->base + GPIO_INT_LEVEL);
 132        writel(reg_both, g->base + GPIO_INT_BOTH_EDGE);
 133
 134        ftgpio_gpio_ack_irq(d);
 135
 136        return 0;
 137}
 138
 139static void ftgpio_gpio_irq_handler(struct irq_desc *desc)
 140{
 141        struct gpio_chip *gc = irq_desc_get_handler_data(desc);
 142        struct ftgpio_gpio *g = gpiochip_get_data(gc);
 143        struct irq_chip *irqchip = irq_desc_get_chip(desc);
 144        int offset;
 145        unsigned long stat;
 146
 147        chained_irq_enter(irqchip, desc);
 148
 149        stat = readl(g->base + GPIO_INT_STAT_RAW);
 150        if (stat)
 151                for_each_set_bit(offset, &stat, gc->ngpio)
 152                        generic_handle_irq(irq_find_mapping(gc->irq.domain,
 153                                                            offset));
 154
 155        chained_irq_exit(irqchip, desc);
 156}
 157
 158static int ftgpio_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
 159                                  unsigned long config)
 160{
 161        enum pin_config_param param = pinconf_to_config_param(config);
 162        u32 arg = pinconf_to_config_argument(config);
 163        struct ftgpio_gpio *g = gpiochip_get_data(gc);
 164        unsigned long pclk_freq;
 165        u32 deb_div;
 166        u32 val;
 167
 168        if (param != PIN_CONFIG_INPUT_DEBOUNCE)
 169                return -ENOTSUPP;
 170
 171        /*
 172         * Debounce only works if interrupts are enabled. The manual
 173         * states that if PCLK is 66 MHz, and this is set to 0x7D0, then
 174         * PCLK is divided down to 33 kHz for the debounce timer. 0x7D0 is
 175         * 2000 decimal, so what they mean is simply that the PCLK is
 176         * divided by this value.
 177         *
 178         * As we get a debounce setting in microseconds, we calculate the
 179         * desired period time and see if we can get a suitable debounce
 180         * time.
 181         */
 182        pclk_freq = clk_get_rate(g->clk);
 183        deb_div = DIV_ROUND_CLOSEST(pclk_freq, arg);
 184
 185        /* This register is only 24 bits wide */
 186        if (deb_div > (1 << 24))
 187                return -ENOTSUPP;
 188
 189        dev_dbg(g->dev, "prescale divisor: %08x, resulting frequency %lu Hz\n",
 190                deb_div, (pclk_freq/deb_div));
 191
 192        val = readl(g->base + GPIO_DEBOUNCE_PRESCALE);
 193        if (val == deb_div) {
 194                /*
 195                 * The debounce timer happens to already be set to the
 196                 * desireable value, what a coincidence! We can just enable
 197                 * debounce on this GPIO line and return. This happens more
 198                 * often than you think, for example when all GPIO keys
 199                 * on a system are requesting the same debounce interval.
 200                 */
 201                val = readl(g->base + GPIO_DEBOUNCE_EN);
 202                val |= BIT(offset);
 203                writel(val, g->base + GPIO_DEBOUNCE_EN);
 204                return 0;
 205        }
 206
 207        val = readl(g->base + GPIO_DEBOUNCE_EN);
 208        if (val) {
 209                /*
 210                 * Oh no! Someone is already using the debounce with
 211                 * another setting than what we need. Bummer.
 212                 */
 213                return -ENOTSUPP;
 214        }
 215
 216        /* First come, first serve */
 217        writel(deb_div, g->base + GPIO_DEBOUNCE_PRESCALE);
 218        /* Enable debounce */
 219        val |= BIT(offset);
 220        writel(val, g->base + GPIO_DEBOUNCE_EN);
 221
 222        return 0;
 223}
 224
 225static int ftgpio_gpio_probe(struct platform_device *pdev)
 226{
 227        struct device *dev = &pdev->dev;
 228        struct ftgpio_gpio *g;
 229        int irq;
 230        int ret;
 231
 232        g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL);
 233        if (!g)
 234                return -ENOMEM;
 235
 236        g->dev = dev;
 237
 238        g->base = devm_platform_ioremap_resource(pdev, 0);
 239        if (IS_ERR(g->base))
 240                return PTR_ERR(g->base);
 241
 242        irq = platform_get_irq(pdev, 0);
 243        if (irq <= 0)
 244                return irq ? irq : -EINVAL;
 245
 246        g->clk = devm_clk_get(dev, NULL);
 247        if (!IS_ERR(g->clk)) {
 248                ret = clk_prepare_enable(g->clk);
 249                if (ret)
 250                        return ret;
 251        } else if (PTR_ERR(g->clk) == -EPROBE_DEFER) {
 252                /*
 253                 * Percolate deferrals, for anything else,
 254                 * just live without the clocking.
 255                 */
 256                return PTR_ERR(g->clk);
 257        }
 258
 259        ret = bgpio_init(&g->gc, dev, 4,
 260                         g->base + GPIO_DATA_IN,
 261                         g->base + GPIO_DATA_SET,
 262                         g->base + GPIO_DATA_CLR,
 263                         g->base + GPIO_DIR,
 264                         NULL,
 265                         0);
 266        if (ret) {
 267                dev_err(dev, "unable to init generic GPIO\n");
 268                goto dis_clk;
 269        }
 270        g->gc.label = "FTGPIO010";
 271        g->gc.base = -1;
 272        g->gc.parent = dev;
 273        g->gc.owner = THIS_MODULE;
 274        /* ngpio is set by bgpio_init() */
 275
 276        /* We need a silicon clock to do debounce */
 277        if (!IS_ERR(g->clk))
 278                g->gc.set_config = ftgpio_gpio_set_config;
 279
 280        ret = devm_gpiochip_add_data(dev, &g->gc, g);
 281        if (ret)
 282                goto dis_clk;
 283
 284        /* Disable, unmask and clear all interrupts */
 285        writel(0x0, g->base + GPIO_INT_EN);
 286        writel(0x0, g->base + GPIO_INT_MASK);
 287        writel(~0x0, g->base + GPIO_INT_CLR);
 288
 289        /* Clear any use of debounce */
 290        writel(0x0, g->base + GPIO_DEBOUNCE_EN);
 291
 292        g->irq.name = "FTGPIO010";
 293        g->irq.irq_ack = ftgpio_gpio_ack_irq;
 294        g->irq.irq_mask = ftgpio_gpio_mask_irq;
 295        g->irq.irq_unmask = ftgpio_gpio_unmask_irq;
 296        g->irq.irq_set_type = ftgpio_gpio_set_irq_type;
 297
 298        ret = gpiochip_irqchip_add(&g->gc, &g->irq,
 299                                   0, handle_bad_irq,
 300                                   IRQ_TYPE_NONE);
 301        if (ret) {
 302                dev_info(dev, "could not add irqchip\n");
 303                goto dis_clk;
 304        }
 305        gpiochip_set_chained_irqchip(&g->gc, &g->irq,
 306                                     irq, ftgpio_gpio_irq_handler);
 307
 308        platform_set_drvdata(pdev, g);
 309        dev_info(dev, "FTGPIO010 @%p registered\n", g->base);
 310
 311        return 0;
 312
 313dis_clk:
 314        if (!IS_ERR(g->clk))
 315                clk_disable_unprepare(g->clk);
 316        return ret;
 317}
 318
 319static int ftgpio_gpio_remove(struct platform_device *pdev)
 320{
 321        struct ftgpio_gpio *g = platform_get_drvdata(pdev);
 322
 323        if (!IS_ERR(g->clk))
 324                clk_disable_unprepare(g->clk);
 325        return 0;
 326}
 327
 328static const struct of_device_id ftgpio_gpio_of_match[] = {
 329        {
 330                .compatible = "cortina,gemini-gpio",
 331        },
 332        {
 333                .compatible = "moxa,moxart-gpio",
 334        },
 335        {
 336                .compatible = "faraday,ftgpio010",
 337        },
 338        {},
 339};
 340
 341static struct platform_driver ftgpio_gpio_driver = {
 342        .driver = {
 343                .name           = "ftgpio010-gpio",
 344                .of_match_table = of_match_ptr(ftgpio_gpio_of_match),
 345        },
 346        .probe = ftgpio_gpio_probe,
 347        .remove = ftgpio_gpio_remove,
 348};
 349builtin_platform_driver(ftgpio_gpio_driver);
 350