linux/drivers/gpio/gpio-msic.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Intel Medfield MSIC GPIO driver>
   4 * Copyright (c) 2011, Intel Corporation.
   5 *
   6 * Author: Mathias Nyman <mathias.nyman@linux.intel.com>
   7 * Based on intel_pmic_gpio.c
   8 */
   9
  10#include <linux/gpio/driver.h>
  11#include <linux/init.h>
  12#include <linux/interrupt.h>
  13#include <linux/kernel.h>
  14#include <linux/mfd/intel_msic.h>
  15#include <linux/platform_device.h>
  16#include <linux/slab.h>
  17
  18/* the offset for the mapping of global gpio pin to irq */
  19#define MSIC_GPIO_IRQ_OFFSET    0x100
  20
  21#define MSIC_GPIO_DIR_IN        0
  22#define MSIC_GPIO_DIR_OUT       BIT(5)
  23#define MSIC_GPIO_TRIG_FALL     BIT(1)
  24#define MSIC_GPIO_TRIG_RISE     BIT(2)
  25
  26/* masks for msic gpio output GPIOxxxxCTLO registers */
  27#define MSIC_GPIO_DIR_MASK      BIT(5)
  28#define MSIC_GPIO_DRV_MASK      BIT(4)
  29#define MSIC_GPIO_REN_MASK      BIT(3)
  30#define MSIC_GPIO_RVAL_MASK     (BIT(2) | BIT(1))
  31#define MSIC_GPIO_DOUT_MASK     BIT(0)
  32
  33/* masks for msic gpio input GPIOxxxxCTLI registers */
  34#define MSIC_GPIO_GLBYP_MASK    BIT(5)
  35#define MSIC_GPIO_DBNC_MASK     (BIT(4) | BIT(3))
  36#define MSIC_GPIO_INTCNT_MASK   (BIT(2) | BIT(1))
  37#define MSIC_GPIO_DIN_MASK      BIT(0)
  38
  39#define MSIC_NUM_GPIO           24
  40
  41struct msic_gpio {
  42        struct platform_device  *pdev;
  43        struct mutex            buslock;
  44        struct gpio_chip        chip;
  45        int                     irq;
  46        unsigned                irq_base;
  47        unsigned long           trig_change_mask;
  48        unsigned                trig_type;
  49};
  50
  51/*
  52 * MSIC has 24 gpios, 16 low voltage (1.2-1.8v) and 8 high voltage (3v).
  53 * Both the high and low voltage gpios are divided in two banks.
  54 * GPIOs are numbered with GPIO0LV0 as gpio_base in the following order:
  55 * GPIO0LV0..GPIO0LV7: low voltage, bank 0, gpio_base
  56 * GPIO1LV0..GPIO1LV7: low voltage, bank 1,  gpio_base + 8
  57 * GPIO0HV0..GPIO0HV3: high voltage, bank 0, gpio_base + 16
  58 * GPIO1HV0..GPIO1HV3: high voltage, bank 1, gpio_base + 20
  59 */
  60
  61static int msic_gpio_to_ireg(unsigned offset)
  62{
  63        if (offset >= MSIC_NUM_GPIO)
  64                return -EINVAL;
  65
  66        if (offset < 8)
  67                return INTEL_MSIC_GPIO0LV0CTLI - offset;
  68        if (offset < 16)
  69                return INTEL_MSIC_GPIO1LV0CTLI - offset + 8;
  70        if (offset < 20)
  71                return INTEL_MSIC_GPIO0HV0CTLI - offset + 16;
  72
  73        return INTEL_MSIC_GPIO1HV0CTLI - offset + 20;
  74}
  75
  76static int msic_gpio_to_oreg(unsigned offset)
  77{
  78        if (offset >= MSIC_NUM_GPIO)
  79                return -EINVAL;
  80
  81        if (offset < 8)
  82                return INTEL_MSIC_GPIO0LV0CTLO - offset;
  83        if (offset < 16)
  84                return INTEL_MSIC_GPIO1LV0CTLO - offset + 8;
  85        if (offset < 20)
  86                return INTEL_MSIC_GPIO0HV0CTLO - offset + 16;
  87
  88        return INTEL_MSIC_GPIO1HV0CTLO - offset + 20;
  89}
  90
  91static int msic_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  92{
  93        int reg;
  94
  95        reg = msic_gpio_to_oreg(offset);
  96        if (reg < 0)
  97                return reg;
  98
  99        return intel_msic_reg_update(reg, MSIC_GPIO_DIR_IN, MSIC_GPIO_DIR_MASK);
 100}
 101
 102static int msic_gpio_direction_output(struct gpio_chip *chip,
 103                        unsigned offset, int value)
 104{
 105        int reg;
 106        unsigned mask;
 107
 108        value = (!!value) | MSIC_GPIO_DIR_OUT;
 109        mask = MSIC_GPIO_DIR_MASK | MSIC_GPIO_DOUT_MASK;
 110
 111        reg = msic_gpio_to_oreg(offset);
 112        if (reg < 0)
 113                return reg;
 114
 115        return intel_msic_reg_update(reg, value, mask);
 116}
 117
 118static int msic_gpio_get(struct gpio_chip *chip, unsigned offset)
 119{
 120        u8 r;
 121        int ret;
 122        int reg;
 123
 124        reg = msic_gpio_to_ireg(offset);
 125        if (reg < 0)
 126                return reg;
 127
 128        ret = intel_msic_reg_read(reg, &r);
 129        if (ret < 0)
 130                return ret;
 131
 132        return !!(r & MSIC_GPIO_DIN_MASK);
 133}
 134
 135static void msic_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 136{
 137        int reg;
 138
 139        reg = msic_gpio_to_oreg(offset);
 140        if (reg < 0)
 141                return;
 142
 143        intel_msic_reg_update(reg, !!value , MSIC_GPIO_DOUT_MASK);
 144}
 145
 146/*
 147 * This is called from genirq with mg->buslock locked and
 148 * irq_desc->lock held. We can not access the scu bus here, so we
 149 * store the change and update in the bus_sync_unlock() function below
 150 */
 151static int msic_irq_type(struct irq_data *data, unsigned type)
 152{
 153        struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
 154        u32 gpio = data->irq - mg->irq_base;
 155
 156        if (gpio >= mg->chip.ngpio)
 157                return -EINVAL;
 158
 159        /* mark for which gpio the trigger changed, protected by buslock */
 160        mg->trig_change_mask |= (1 << gpio);
 161        mg->trig_type = type;
 162
 163        return 0;
 164}
 165
 166static int msic_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 167{
 168        struct msic_gpio *mg = gpiochip_get_data(chip);
 169        return mg->irq_base + offset;
 170}
 171
 172static void msic_bus_lock(struct irq_data *data)
 173{
 174        struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
 175        mutex_lock(&mg->buslock);
 176}
 177
 178static void msic_bus_sync_unlock(struct irq_data *data)
 179{
 180        struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
 181        int offset;
 182        int reg;
 183        u8 trig = 0;
 184
 185        /* We can only get one change at a time as the buslock covers the
 186           entire transaction. The irq_desc->lock is dropped before we are
 187           called but that is fine */
 188        if (mg->trig_change_mask) {
 189                offset = __ffs(mg->trig_change_mask);
 190
 191                reg = msic_gpio_to_ireg(offset);
 192                if (reg < 0)
 193                        goto out;
 194
 195                if (mg->trig_type & IRQ_TYPE_EDGE_RISING)
 196                        trig |= MSIC_GPIO_TRIG_RISE;
 197                if (mg->trig_type & IRQ_TYPE_EDGE_FALLING)
 198                        trig |= MSIC_GPIO_TRIG_FALL;
 199
 200                intel_msic_reg_update(reg, trig, MSIC_GPIO_INTCNT_MASK);
 201                mg->trig_change_mask = 0;
 202        }
 203out:
 204        mutex_unlock(&mg->buslock);
 205}
 206
 207/* Firmware does all the masking and unmasking for us, no masking here. */
 208static void msic_irq_unmask(struct irq_data *data) { }
 209
 210static void msic_irq_mask(struct irq_data *data) { }
 211
 212static struct irq_chip msic_irqchip = {
 213        .name                   = "MSIC-GPIO",
 214        .irq_mask               = msic_irq_mask,
 215        .irq_unmask             = msic_irq_unmask,
 216        .irq_set_type           = msic_irq_type,
 217        .irq_bus_lock           = msic_bus_lock,
 218        .irq_bus_sync_unlock    = msic_bus_sync_unlock,
 219};
 220
 221static void msic_gpio_irq_handler(struct irq_desc *desc)
 222{
 223        struct irq_data *data = irq_desc_get_irq_data(desc);
 224        struct msic_gpio *mg = irq_data_get_irq_handler_data(data);
 225        struct irq_chip *chip = irq_data_get_irq_chip(data);
 226        struct intel_msic *msic = pdev_to_intel_msic(mg->pdev);
 227        unsigned long pending;
 228        int i;
 229        int bitnr;
 230        u8 pin;
 231
 232        for (i = 0; i < (mg->chip.ngpio / BITS_PER_BYTE); i++) {
 233                intel_msic_irq_read(msic, INTEL_MSIC_GPIO0LVIRQ + i, &pin);
 234                pending = pin;
 235
 236                for_each_set_bit(bitnr, &pending, BITS_PER_BYTE)
 237                        generic_handle_irq(mg->irq_base + i * BITS_PER_BYTE + bitnr);
 238        }
 239        chip->irq_eoi(data);
 240}
 241
 242static int platform_msic_gpio_probe(struct platform_device *pdev)
 243{
 244        struct device *dev = &pdev->dev;
 245        struct intel_msic_gpio_pdata *pdata = dev_get_platdata(dev);
 246        struct msic_gpio *mg;
 247        int irq = platform_get_irq(pdev, 0);
 248        int retval;
 249        int i;
 250
 251        if (irq < 0) {
 252                dev_err(dev, "no IRQ line: %d\n", irq);
 253                return irq;
 254        }
 255
 256        if (!pdata || !pdata->gpio_base) {
 257                dev_err(dev, "incorrect or missing platform data\n");
 258                return -EINVAL;
 259        }
 260
 261        mg = kzalloc(sizeof(*mg), GFP_KERNEL);
 262        if (!mg)
 263                return -ENOMEM;
 264
 265        dev_set_drvdata(dev, mg);
 266
 267        mg->pdev = pdev;
 268        mg->irq = irq;
 269        mg->irq_base = pdata->gpio_base + MSIC_GPIO_IRQ_OFFSET;
 270        mg->chip.label = "msic_gpio";
 271        mg->chip.direction_input = msic_gpio_direction_input;
 272        mg->chip.direction_output = msic_gpio_direction_output;
 273        mg->chip.get = msic_gpio_get;
 274        mg->chip.set = msic_gpio_set;
 275        mg->chip.to_irq = msic_gpio_to_irq;
 276        mg->chip.base = pdata->gpio_base;
 277        mg->chip.ngpio = MSIC_NUM_GPIO;
 278        mg->chip.can_sleep = true;
 279        mg->chip.parent = dev;
 280
 281        mutex_init(&mg->buslock);
 282
 283        retval = gpiochip_add_data(&mg->chip, mg);
 284        if (retval) {
 285                dev_err(dev, "Adding MSIC gpio chip failed\n");
 286                goto err;
 287        }
 288
 289        for (i = 0; i < mg->chip.ngpio; i++) {
 290                irq_set_chip_data(i + mg->irq_base, mg);
 291                irq_set_chip_and_handler(i + mg->irq_base,
 292                                         &msic_irqchip,
 293                                         handle_simple_irq);
 294        }
 295        irq_set_chained_handler_and_data(mg->irq, msic_gpio_irq_handler, mg);
 296
 297        return 0;
 298err:
 299        kfree(mg);
 300        return retval;
 301}
 302
 303static struct platform_driver platform_msic_gpio_driver = {
 304        .driver = {
 305                .name           = "msic_gpio",
 306        },
 307        .probe          = platform_msic_gpio_probe,
 308};
 309
 310static int __init platform_msic_gpio_init(void)
 311{
 312        return platform_driver_register(&platform_msic_gpio_driver);
 313}
 314subsys_initcall(platform_msic_gpio_init);
 315