drivers/gpio/gpio-msic.c

   1 /*
   2  * Intel Medfield MSIC GPIO driver>
   3  * Copyright (c) 2011, Intel Corporation.
   4  *
   5  * Author: Mathias Nyman <mathias.nyman@linux.intel.com>
   6  * Based on intel_pmic_gpio.c
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/slab.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/init.h>
  28 #include <linux/gpio.h>
  29 #include <linux/platform_device.h>
  30 #include <linux/mfd/intel_msic.h>
  31
  32 /* the offset for the mapping of global gpio pin to irq */
  33 #define MSIC_GPIO_IRQ_OFFSET    0x100
  34
  35 #define MSIC_GPIO_DIR_IN        0
  36 #define MSIC_GPIO_DIR_OUT       BIT(5)
  37 #define MSIC_GPIO_TRIG_FALL     BIT(1)
  38 #define MSIC_GPIO_TRIG_RISE     BIT(2)
  39
  40 /* masks for msic gpio output GPIOxxxxCTLO registers */
  41 #define MSIC_GPIO_DIR_MASK      BIT(5)
  42 #define MSIC_GPIO_DRV_MASK      BIT(4)
  43 #define MSIC_GPIO_REN_MASK      BIT(3)
  44 #define MSIC_GPIO_RVAL_MASK     (BIT(2) | BIT(1))
  45 #define MSIC_GPIO_DOUT_MASK     BIT(0)
  46
  47 /* masks for msic gpio input GPIOxxxxCTLI registers */
  48 #define MSIC_GPIO_GLBYP_MASK    BIT(5)
  49 #define MSIC_GPIO_DBNC_MASK     (BIT(4) | BIT(3))
  50 #define MSIC_GPIO_INTCNT_MASK   (BIT(2) | BIT(1))
  51 #define MSIC_GPIO_DIN_MASK      BIT(0)
  52
  53 #define MSIC_NUM_GPIO           24
  54
  55 struct msic_gpio {
  56         struct platform_device  *pdev;
  57         struct mutex            buslock;
  58         struct gpio_chip        chip;
  59         int                     irq;
  60         unsigned                irq_base;
  61         unsigned long           trig_change_mask;
  62         unsigned                trig_type;
  63 };
  64
  65 /*
  66  * MSIC has 24 gpios, 16 low voltage (1.2-1.8v) and 8 high voltage (3v).
  67  * Both the high and low voltage gpios are divided in two banks.
  68  * GPIOs are numbered with GPIO0LV0 as gpio_base in the following order:
  69  * GPIO0LV0..GPIO0LV7: low voltage, bank 0, gpio_base
  70  * GPIO1LV0..GPIO1LV7: low voltage, bank 1,  gpio_base + 8
  71  * GPIO0HV0..GPIO0HV3: high voltage, bank 0, gpio_base + 16
  72  * GPIO1HV0..GPIO1HV3: high voltage, bank 1, gpio_base + 20
  73  */
  74
  75 static int msic_gpio_to_ireg(unsigned offset)
  76 {
  77         if (offset >= MSIC_NUM_GPIO)
  78                 return -EINVAL;
  79
  80         if (offset < 8)
  81                 return INTEL_MSIC_GPIO0LV0CTLI - offset;
  82         if (offset < 16)
  83                 return INTEL_MSIC_GPIO1LV0CTLI - offset + 8;
  84         if (offset < 20)
  85                 return INTEL_MSIC_GPIO0HV0CTLI - offset + 16;
  86
  87         return INTEL_MSIC_GPIO1HV0CTLI - offset + 20;
  88 }
  89
  90 static int msic_gpio_to_oreg(unsigned offset)
  91 {
  92         if (offset >= MSIC_NUM_GPIO)
  93                 return -EINVAL;
  94
  95         if (offset < 8)
  96                 return INTEL_MSIC_GPIO0LV0CTLO - offset;
  97         if (offset < 16)
  98                 return INTEL_MSIC_GPIO1LV0CTLO - offset + 8;
  99         if (offset < 20)
 100                 return INTEL_MSIC_GPIO0HV0CTLO - offset + 16;
 101
 102         return INTEL_MSIC_GPIO1HV0CTLO - offset + 20;
 103 }
 104
 105 static int msic_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 106 {
 107         int reg;
 108
 109         reg = msic_gpio_to_oreg(offset);
 110         if (reg < 0)
 111                 return reg;
 112
 113         return intel_msic_reg_update(reg, MSIC_GPIO_DIR_IN, MSIC_GPIO_DIR_MASK);
 114 }
 115
 116 static int msic_gpio_direction_output(struct gpio_chip *chip,
 117                         unsigned offset, int value)
 118 {
 119         int reg;
 120         unsigned mask;
 121
 122         value = (!!value) | MSIC_GPIO_DIR_OUT;
 123         mask = MSIC_GPIO_DIR_MASK | MSIC_GPIO_DOUT_MASK;
 124
 125         reg = msic_gpio_to_oreg(offset);
 126         if (reg < 0)
 127                 return reg;
 128
 129         return intel_msic_reg_update(reg, value, mask);
 130 }
 131
 132 static int msic_gpio_get(struct gpio_chip *chip, unsigned offset)
 133 {
 134         u8 r;
 135         int ret;
 136         int reg;
 137
 138         reg = msic_gpio_to_ireg(offset);
 139         if (reg < 0)
 140                 return reg;
 141
 142         ret = intel_msic_reg_read(reg, &r);
 143         if (ret < 0)
 144                 return ret;
 145
 146         return r & MSIC_GPIO_DIN_MASK;
 147 }
 148
 149 static void msic_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 150 {
 151         int reg;
 152
 153         reg = msic_gpio_to_oreg(offset);
 154         if (reg < 0)
 155                 return;
 156
 157         intel_msic_reg_update(reg, !!value , MSIC_GPIO_DOUT_MASK);
 158 }
 159
 160 /*
 161  * This is called from genirq with mg->buslock locked and
 162  * irq_desc->lock held. We can not access the scu bus here, so we
 163  * store the change and update in the bus_sync_unlock() function below
 164  */
 165 static int msic_irq_type(struct irq_data *data, unsigned type)
 166 {
 167         struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
 168         u32 gpio = data->irq - mg->irq_base;
 169
 170         if (gpio >= mg->chip.ngpio)
 171                 return -EINVAL;
 172
 173         /* mark for which gpio the trigger changed, protected by buslock */
 174         mg->trig_change_mask |= (1 << gpio);
 175         mg->trig_type = type;
 176
 177         return 0;
 178 }
 179
 180 static int msic_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 181 {
 182         struct msic_gpio *mg = container_of(chip, struct msic_gpio, chip);
 183         return mg->irq_base + offset;
 184 }
 185
 186 static void msic_bus_lock(struct irq_data *data)
 187 {
 188         struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
 189         mutex_lock(&mg->buslock);
 190 }
 191
 192 static void msic_bus_sync_unlock(struct irq_data *data)
 193 {
 194         struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
 195         int offset;
 196         int reg;
 197         u8 trig = 0;
 198
 199         /* We can only get one change at a time as the buslock covers the
 200            entire transaction. The irq_desc->lock is dropped before we are
 201            called but that is fine */
 202         if (mg->trig_change_mask) {
 203                 offset = __ffs(mg->trig_change_mask);
 204
 205                 reg = msic_gpio_to_ireg(offset);
 206                 if (reg < 0)
 207                         goto out;
 208
 209                 if (mg->trig_type & IRQ_TYPE_EDGE_RISING)
 210                         trig |= MSIC_GPIO_TRIG_RISE;
 211                 if (mg->trig_type & IRQ_TYPE_EDGE_FALLING)
 212                         trig |= MSIC_GPIO_TRIG_FALL;
 213
 214                 intel_msic_reg_update(reg, trig, MSIC_GPIO_INTCNT_MASK);
 215                 mg->trig_change_mask = 0;
 216         }
 217 out:
 218         mutex_unlock(&mg->buslock);
 219 }
 220
 221 /* Firmware does all the masking and unmasking for us, no masking here. */
 222 static void msic_irq_unmask(struct irq_data *data) { }
 223
 224 static void msic_irq_mask(struct irq_data *data) { }
 225
 226 static struct irq_chip msic_irqchip = {
 227         .name                   = "MSIC-GPIO",
 228         .irq_mask               = msic_irq_mask,
 229         .irq_unmask             = msic_irq_unmask,
 230         .irq_set_type           = msic_irq_type,
 231         .irq_bus_lock           = msic_bus_lock,
 232         .irq_bus_sync_unlock    = msic_bus_sync_unlock,
 233 };
 234
 235 static void msic_gpio_irq_handler(unsigned irq, struct irq_desc *desc)
 236 {
 237         struct irq_data *data = irq_desc_get_irq_data(desc);
 238         struct msic_gpio *mg = irq_data_get_irq_handler_data(data);
 239         struct irq_chip *chip = irq_data_get_irq_chip(data);
 240         struct intel_msic *msic = pdev_to_intel_msic(mg->pdev);
 241         int i;
 242         int bitnr;
 243         u8 pin;
 244         unsigned long pending = 0;
 245
 246         for (i = 0; i < (mg->chip.ngpio / BITS_PER_BYTE); i++) {
 247                 intel_msic_irq_read(msic, INTEL_MSIC_GPIO0LVIRQ + i, &pin);
 248                 pending = pin;
 249
 250                 if (pending) {
 251                         for_each_set_bit(bitnr, &pending, BITS_PER_BYTE)
 252                                 generic_handle_irq(mg->irq_base +
 253                                                    (i * BITS_PER_BYTE) + bitnr);
 254                 }
 255         }
 256         chip->irq_eoi(data);
 257 }
 258
 259 static int platform_msic_gpio_probe(struct platform_device *pdev)
 260 {
 261         struct device *dev = &pdev->dev;
 262         struct intel_msic_gpio_pdata *pdata = dev->platform_data;
 263         struct msic_gpio *mg;
 264         int irq = platform_get_irq(pdev, 0);
 265         int retval;
 266         int i;
 267
 268         if (irq < 0) {
 269                 dev_err(dev, "no IRQ line\n");
 270                 return -EINVAL;
 271         }
 272
 273         if (!pdata || !pdata->gpio_base) {
 274                 dev_err(dev, "incorrect or missing platform data\n");
 275                 return -EINVAL;
 276         }
 277
 278         mg = kzalloc(sizeof(*mg), GFP_KERNEL);
 279         if (!mg)
 280                 return -ENOMEM;
 281
 282         dev_set_drvdata(dev, mg);
 283
 284         mg->pdev = pdev;
 285         mg->irq = irq;
 286         mg->irq_base = pdata->gpio_base + MSIC_GPIO_IRQ_OFFSET;
 287         mg->chip.label = "msic_gpio";
 288         mg->chip.direction_input = msic_gpio_direction_input;
 289         mg->chip.direction_output = msic_gpio_direction_output;
 290         mg->chip.get = msic_gpio_get;
 291         mg->chip.set = msic_gpio_set;
 292         mg->chip.to_irq = msic_gpio_to_irq;
 293         mg->chip.base = pdata->gpio_base;
 294         mg->chip.ngpio = MSIC_NUM_GPIO;
 295         mg->chip.can_sleep = 1;
 296         mg->chip.dev = dev;
 297
 298         mutex_init(&mg->buslock);
 299
 300         retval = gpiochip_add(&mg->chip);
 301         if (retval) {
 302                 dev_err(dev, "Adding MSIC gpio chip failed\n");
 303                 goto err;
 304         }
 305
 306         for (i = 0; i < mg->chip.ngpio; i++) {
 307                 irq_set_chip_data(i + mg->irq_base, mg);
 308                 irq_set_chip_and_handler_name(i + mg->irq_base,
 309                                               &msic_irqchip,
 310                                               handle_simple_irq,
 311                                               "demux");
 312         }
 313         irq_set_chained_handler(mg->irq, msic_gpio_irq_handler);
 314         irq_set_handler_data(mg->irq, mg);
 315
 316         return 0;
 317 err:
 318         kfree(mg);
 319         return retval;
 320 }
 321
 322 static struct platform_driver platform_msic_gpio_driver = {
 323         .driver = {
 324                 .name           = "msic_gpio",
 325                 .owner          = THIS_MODULE,
 326         },
 327         .probe          = platform_msic_gpio_probe,
 328 };
 329
 330 static int __init platform_msic_gpio_init(void)
 331 {
 332         return platform_driver_register(&platform_msic_gpio_driver);
 333 }
 334
 335 subsys_initcall(platform_msic_gpio_init);
 336
 337 MODULE_AUTHOR("Mathias Nyman <mathias.nyman@linux.intel.com>");
 338 MODULE_DESCRIPTION("Intel Medfield MSIC GPIO driver");
 339 MODULE_LICENSE("GPL v2");