linux/drivers/usb/misc/brcmstb-usb-pinmap.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/* Copyright (c) 2020, Broadcom */
   3
   4#include <linux/init.h>
   5#include <linux/types.h>
   6#include <linux/module.h>
   7#include <linux/platform_device.h>
   8#include <linux/interrupt.h>
   9#include <linux/io.h>
  10#include <linux/device.h>
  11#include <linux/of.h>
  12#include <linux/kernel.h>
  13#include <linux/kdebug.h>
  14#include <linux/gpio/consumer.h>
  15
  16struct out_pin {
  17        u32 enable_mask;
  18        u32 value_mask;
  19        u32 changed_mask;
  20        u32 clr_changed_mask;
  21        struct gpio_desc *gpiod;
  22        const char *name;
  23};
  24
  25struct in_pin {
  26        u32 enable_mask;
  27        u32 value_mask;
  28        struct gpio_desc *gpiod;
  29        const char *name;
  30        struct brcmstb_usb_pinmap_data *pdata;
  31};
  32
  33struct brcmstb_usb_pinmap_data {
  34        void __iomem *regs;
  35        int in_count;
  36        struct in_pin *in_pins;
  37        int out_count;
  38        struct out_pin *out_pins;
  39};
  40
  41
  42static void pinmap_set(void __iomem *reg, u32 mask)
  43{
  44        u32 val;
  45
  46        val = readl(reg);
  47        val |= mask;
  48        writel(val, reg);
  49}
  50
  51static void pinmap_unset(void __iomem *reg, u32 mask)
  52{
  53        u32 val;
  54
  55        val = readl(reg);
  56        val &= ~mask;
  57        writel(val, reg);
  58}
  59
  60static void sync_in_pin(struct in_pin *pin)
  61{
  62        u32 val;
  63
  64        val = gpiod_get_value(pin->gpiod);
  65        if (val)
  66                pinmap_set(pin->pdata->regs, pin->value_mask);
  67        else
  68                pinmap_unset(pin->pdata->regs, pin->value_mask);
  69}
  70
  71/*
  72 * Interrupt from override register, propagate from override bit
  73 * to GPIO.
  74 */
  75static irqreturn_t brcmstb_usb_pinmap_ovr_isr(int irq, void *dev_id)
  76{
  77        struct brcmstb_usb_pinmap_data *pdata = dev_id;
  78        struct out_pin *pout;
  79        u32 val;
  80        u32 bit;
  81        int x;
  82
  83        pr_debug("%s: reg: 0x%x\n", __func__, readl(pdata->regs));
  84        pout = pdata->out_pins;
  85        for (x = 0; x < pdata->out_count; x++) {
  86                val = readl(pdata->regs);
  87                if (val & pout->changed_mask) {
  88                        pinmap_set(pdata->regs, pout->clr_changed_mask);
  89                        pinmap_unset(pdata->regs, pout->clr_changed_mask);
  90                        bit = val & pout->value_mask;
  91                        gpiod_set_value(pout->gpiod, bit ? 1 : 0);
  92                        pr_debug("%s: %s bit changed state to %d\n",
  93                                 __func__, pout->name, bit ? 1 : 0);
  94                }
  95        }
  96        return IRQ_HANDLED;
  97}
  98
  99/*
 100 * Interrupt from GPIO, propagate from GPIO to override bit.
 101 */
 102static irqreturn_t brcmstb_usb_pinmap_gpio_isr(int irq, void *dev_id)
 103{
 104        struct in_pin *pin = dev_id;
 105
 106        pr_debug("%s: %s pin changed state\n", __func__, pin->name);
 107        sync_in_pin(pin);
 108        return IRQ_HANDLED;
 109}
 110
 111
 112static void get_pin_counts(struct device_node *dn, int *in_count,
 113                           int *out_count)
 114{
 115        int in;
 116        int out;
 117
 118        *in_count = 0;
 119        *out_count = 0;
 120        in = of_property_count_strings(dn, "brcm,in-functions");
 121        if (in < 0)
 122                return;
 123        out = of_property_count_strings(dn, "brcm,out-functions");
 124        if (out < 0)
 125                return;
 126        *in_count = in;
 127        *out_count = out;
 128}
 129
 130static int parse_pins(struct device *dev, struct device_node *dn,
 131                      struct brcmstb_usb_pinmap_data *pdata)
 132{
 133        struct out_pin *pout;
 134        struct in_pin *pin;
 135        int index;
 136        int res;
 137        int x;
 138
 139        pin = pdata->in_pins;
 140        for (x = 0, index = 0; x < pdata->in_count; x++) {
 141                pin->gpiod = devm_gpiod_get_index(dev, "in", x, GPIOD_IN);
 142                if (IS_ERR(pin->gpiod)) {
 143                        dev_err(dev, "Error getting gpio %s\n", pin->name);
 144                        return PTR_ERR(pin->gpiod);
 145
 146                }
 147                res = of_property_read_string_index(dn, "brcm,in-functions", x,
 148                                                    &pin->name);
 149                if (res < 0) {
 150                        dev_err(dev, "Error getting brcm,in-functions for %s\n",
 151                                pin->name);
 152                        return res;
 153                }
 154                res = of_property_read_u32_index(dn, "brcm,in-masks", index++,
 155                                                 &pin->enable_mask);
 156                if (res < 0) {
 157                        dev_err(dev, "Error getting 1st brcm,in-masks for %s\n",
 158                                pin->name);
 159                        return res;
 160                }
 161                res = of_property_read_u32_index(dn, "brcm,in-masks", index++,
 162                                                 &pin->value_mask);
 163                if (res < 0) {
 164                        dev_err(dev, "Error getting 2nd brcm,in-masks for %s\n",
 165                                pin->name);
 166                        return res;
 167                }
 168                pin->pdata = pdata;
 169                pin++;
 170        }
 171        pout = pdata->out_pins;
 172        for (x = 0, index = 0; x < pdata->out_count; x++) {
 173                pout->gpiod = devm_gpiod_get_index(dev, "out", x,
 174                                                   GPIOD_OUT_HIGH);
 175                if (IS_ERR(pout->gpiod)) {
 176                        dev_err(dev, "Error getting gpio %s\n", pin->name);
 177                        return PTR_ERR(pout->gpiod);
 178                }
 179                res = of_property_read_string_index(dn, "brcm,out-functions", x,
 180                                                    &pout->name);
 181                if (res < 0) {
 182                        dev_err(dev, "Error getting brcm,out-functions for %s\n",
 183                                pout->name);
 184                        return res;
 185                }
 186                res = of_property_read_u32_index(dn, "brcm,out-masks", index++,
 187                                                 &pout->enable_mask);
 188                if (res < 0) {
 189                        dev_err(dev, "Error getting 1st brcm,out-masks for %s\n",
 190                                pout->name);
 191                        return res;
 192                }
 193                res = of_property_read_u32_index(dn, "brcm,out-masks", index++,
 194                                                 &pout->value_mask);
 195                if (res < 0) {
 196                        dev_err(dev, "Error getting 2nd brcm,out-masks for %s\n",
 197                                pout->name);
 198                        return res;
 199                }
 200                res = of_property_read_u32_index(dn, "brcm,out-masks", index++,
 201                                                 &pout->changed_mask);
 202                if (res < 0) {
 203                        dev_err(dev, "Error getting 3rd brcm,out-masks for %s\n",
 204                                pout->name);
 205                        return res;
 206                }
 207                res = of_property_read_u32_index(dn, "brcm,out-masks", index++,
 208                                                 &pout->clr_changed_mask);
 209                if (res < 0) {
 210                        dev_err(dev, "Error getting 4th out-masks for %s\n",
 211                                pout->name);
 212                        return res;
 213                }
 214                pout++;
 215        }
 216        return 0;
 217}
 218
 219static void sync_all_pins(struct brcmstb_usb_pinmap_data *pdata)
 220{
 221        struct out_pin *pout;
 222        struct in_pin *pin;
 223        int val;
 224        int x;
 225
 226        /*
 227         * Enable the override, clear any changed condition and
 228         * propagate the state to the GPIO for all out pins.
 229         */
 230        pout = pdata->out_pins;
 231        for (x = 0; x < pdata->out_count; x++) {
 232                pinmap_set(pdata->regs, pout->enable_mask);
 233                pinmap_set(pdata->regs, pout->clr_changed_mask);
 234                pinmap_unset(pdata->regs, pout->clr_changed_mask);
 235                val = readl(pdata->regs) & pout->value_mask;
 236                gpiod_set_value(pout->gpiod, val ? 1 : 0);
 237                pout++;
 238        }
 239
 240        /* sync and enable all in pins. */
 241        pin = pdata->in_pins;
 242        for (x = 0; x < pdata->in_count; x++) {
 243                sync_in_pin(pin);
 244                pinmap_set(pdata->regs, pin->enable_mask);
 245                pin++;
 246        }
 247}
 248
 249static int __init brcmstb_usb_pinmap_probe(struct platform_device *pdev)
 250{
 251        struct device_node *dn = pdev->dev.of_node;
 252        struct brcmstb_usb_pinmap_data *pdata;
 253        struct in_pin *pin;
 254        struct resource *r;
 255        int out_count;
 256        int in_count;
 257        int err;
 258        int irq;
 259        int x;
 260
 261        get_pin_counts(dn, &in_count, &out_count);
 262        if ((in_count + out_count) == 0)
 263                return -EINVAL;
 264
 265        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 266        if (!r)
 267                return -EINVAL;
 268
 269        pdata = devm_kzalloc(&pdev->dev,
 270                             sizeof(*pdata) +
 271                             (sizeof(struct in_pin) * in_count) +
 272                             (sizeof(struct out_pin) * out_count), GFP_KERNEL);
 273        if (!pdata)
 274                return -ENOMEM;
 275
 276        pdata->in_count = in_count;
 277        pdata->out_count = out_count;
 278        pdata->in_pins = (struct in_pin *)(pdata + 1);
 279        pdata->out_pins = (struct out_pin *)(pdata->in_pins + in_count);
 280
 281        pdata->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
 282        if (!pdata->regs)
 283                return -ENOMEM;
 284        platform_set_drvdata(pdev, pdata);
 285
 286        err = parse_pins(&pdev->dev, dn, pdata);
 287        if (err)
 288                return err;
 289
 290        sync_all_pins(pdata);
 291
 292        if (out_count) {
 293
 294                /* Enable interrupt for out pins */
 295                irq = platform_get_irq(pdev, 0);
 296                if (irq < 0)
 297                        return irq;
 298                err = devm_request_irq(&pdev->dev, irq,
 299                                       brcmstb_usb_pinmap_ovr_isr,
 300                                       IRQF_TRIGGER_RISING,
 301                                       pdev->name, pdata);
 302                if (err < 0) {
 303                        dev_err(&pdev->dev, "Error requesting IRQ\n");
 304                        return err;
 305                }
 306        }
 307
 308        for (x = 0, pin = pdata->in_pins; x < pdata->in_count; x++, pin++) {
 309                irq = gpiod_to_irq(pin->gpiod);
 310                if (irq < 0) {
 311                        dev_err(&pdev->dev, "Error getting IRQ for %s pin\n",
 312                                pin->name);
 313                        return irq;
 314                }
 315                err = devm_request_irq(&pdev->dev, irq,
 316                                       brcmstb_usb_pinmap_gpio_isr,
 317                                       IRQF_SHARED | IRQF_TRIGGER_RISING |
 318                                       IRQF_TRIGGER_FALLING,
 319                                       pdev->name, pin);
 320                if (err < 0) {
 321                        dev_err(&pdev->dev, "Error requesting IRQ for %s pin\n",
 322                                pin->name);
 323                        return err;
 324                }
 325        }
 326
 327        dev_dbg(&pdev->dev, "Driver probe succeeded\n");
 328        dev_dbg(&pdev->dev, "In pin count: %d, out pin count: %d\n",
 329                pdata->in_count, pdata->out_count);
 330        return 0;
 331}
 332
 333
 334static const struct of_device_id brcmstb_usb_pinmap_of_match[] = {
 335        { .compatible = "brcm,usb-pinmap" },
 336        { },
 337};
 338
 339static struct platform_driver brcmstb_usb_pinmap_driver = {
 340        .driver = {
 341                .name   = "brcm-usb-pinmap",
 342                .of_match_table = brcmstb_usb_pinmap_of_match,
 343        },
 344};
 345
 346static int __init brcmstb_usb_pinmap_init(void)
 347{
 348        return platform_driver_probe(&brcmstb_usb_pinmap_driver,
 349                                     brcmstb_usb_pinmap_probe);
 350}
 351
 352module_init(brcmstb_usb_pinmap_init);
 353MODULE_AUTHOR("Al Cooper <alcooperx@gmail.com>");
 354MODULE_DESCRIPTION("Broadcom USB Pinmap Driver");
 355MODULE_LICENSE("GPL");
 356