drivers/gpio/gpio-ftgpio010.c

   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  */
  48 struct 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
  56 static 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
  64 static 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
  75 static 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
  86 static 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
 139 static 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
 158 static 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
 225 static int ftgpio_gpio_probe(struct platform_device *pdev)
 226 {
 227         struct device *dev = &pdev->dev;
 228         struct ftgpio_gpio *g;
 229         struct gpio_irq_chip *girq;
 230         int irq;
 231         int ret;
 232
 233         g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL);
 234         if (!g)
 235                 return -ENOMEM;
 236
 237         g->dev = dev;
 238
 239         g->base = devm_platform_ioremap_resource(pdev, 0);
 240         if (IS_ERR(g->base))
 241                 return PTR_ERR(g->base);
 242
 243         irq = platform_get_irq(pdev, 0);
 244         if (irq <= 0)
 245                 return irq ? irq : -EINVAL;
 246
 247         g->clk = devm_clk_get(dev, NULL);
 248         if (!IS_ERR(g->clk)) {
 249                 ret = clk_prepare_enable(g->clk);
 250                 if (ret)
 251                         return ret;
 252         } else if (PTR_ERR(g->clk) == -EPROBE_DEFER) {
 253                 /*
 254                  * Percolate deferrals, for anything else,
 255                  * just live without the clocking.
 256                  */
 257                 return PTR_ERR(g->clk);
 258         }
 259
 260         ret = bgpio_init(&g->gc, dev, 4,
 261                          g->base + GPIO_DATA_IN,
 262                          g->base + GPIO_DATA_SET,
 263                          g->base + GPIO_DATA_CLR,
 264                          g->base + GPIO_DIR,
 265                          NULL,
 266                          0);
 267         if (ret) {
 268                 dev_err(dev, "unable to init generic GPIO\n");
 269                 goto dis_clk;
 270         }
 271         g->gc.label = "FTGPIO010";
 272         g->gc.base = -1;
 273         g->gc.parent = dev;
 274         g->gc.owner = THIS_MODULE;
 275         /* ngpio is set by bgpio_init() */
 276
 277         /* We need a silicon clock to do debounce */
 278         if (!IS_ERR(g->clk))
 279                 g->gc.set_config = ftgpio_gpio_set_config;
 280
 281         g->irq.name = "FTGPIO010";
 282         g->irq.irq_ack = ftgpio_gpio_ack_irq;
 283         g->irq.irq_mask = ftgpio_gpio_mask_irq;
 284         g->irq.irq_unmask = ftgpio_gpio_unmask_irq;
 285         g->irq.irq_set_type = ftgpio_gpio_set_irq_type;
 286
 287         girq = &g->gc.irq;
 288         girq->chip = &g->irq;
 289         girq->parent_handler = ftgpio_gpio_irq_handler;
 290         girq->num_parents = 1;
 291         girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents),
 292                                      GFP_KERNEL);
 293         if (!girq->parents) {
 294                 ret = -ENOMEM;
 295                 goto dis_clk;
 296         }
 297         girq->default_type = IRQ_TYPE_NONE;
 298         girq->handler = handle_bad_irq;
 299         girq->parents[0] = irq;
 300
 301         /* Disable, unmask and clear all interrupts */
 302         writel(0x0, g->base + GPIO_INT_EN);
 303         writel(0x0, g->base + GPIO_INT_MASK);
 304         writel(~0x0, g->base + GPIO_INT_CLR);
 305
 306         /* Clear any use of debounce */
 307         writel(0x0, g->base + GPIO_DEBOUNCE_EN);
 308
 309         ret = devm_gpiochip_add_data(dev, &g->gc, g);
 310         if (ret)
 311                 goto dis_clk;
 312
 313         platform_set_drvdata(pdev, g);
 314         dev_info(dev, "FTGPIO010 @%p registered\n", g->base);
 315
 316         return 0;
 317
 318 dis_clk:
 319         if (!IS_ERR(g->clk))
 320                 clk_disable_unprepare(g->clk);
 321         return ret;
 322 }
 323
 324 static int ftgpio_gpio_remove(struct platform_device *pdev)
 325 {
 326         struct ftgpio_gpio *g = platform_get_drvdata(pdev);
 327
 328         if (!IS_ERR(g->clk))
 329                 clk_disable_unprepare(g->clk);
 330         return 0;
 331 }
 332
 333 static const struct of_device_id ftgpio_gpio_of_match[] = {
 334         {
 335                 .compatible = "cortina,gemini-gpio",
 336         },
 337         {
 338                 .compatible = "moxa,moxart-gpio",
 339         },
 340         {
 341                 .compatible = "faraday,ftgpio010",
 342         },
 343         {},
 344 };
 345
 346 static struct platform_driver ftgpio_gpio_driver = {
 347         .driver = {
 348                 .name           = "ftgpio010-gpio",
 349                 .of_match_table = of_match_ptr(ftgpio_gpio_of_match),
 350         },
 351         .probe = ftgpio_gpio_probe,
 352         .remove = ftgpio_gpio_remove,
 353 };
 354 builtin_platform_driver(ftgpio_gpio_driver);