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