drivers/gpio/gpio-msic.c

   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
  41 struct 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
  61 static 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
  76 static 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
  91 static 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
 102 static 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
 118 static 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
 135 static 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  */
 151 static 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
 166 static 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
 172 static 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
 178 static 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         }
 203 out:
 204         mutex_unlock(&mg->buslock);
 205 }
 206
 207 /* Firmware does all the masking and unmasking for us, no masking here. */
 208 static void msic_irq_unmask(struct irq_data *data) { }
 209
 210 static void msic_irq_mask(struct irq_data *data) { }
 211
 212 static 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
 221 static 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
 242 static 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;
 298 err:
 299         kfree(mg);
 300         return retval;
 301 }
 302
 303 static struct platform_driver platform_msic_gpio_driver = {
 304         .driver = {
 305                 .name           = "msic_gpio",
 306         },
 307         .probe          = platform_msic_gpio_probe,
 308 };
 309
 310 static int __init platform_msic_gpio_init(void)
 311 {
 312         return platform_driver_register(&platform_msic_gpio_driver);
 313 }
 314 subsys_initcall(platform_msic_gpio_init);