target/linux/bcm27xx/patches-5.15/950-0086-bcm2835-virtgpio-Virtual-GPIO-driver.patch

   1 From 8b716d25755e304de06ce150a9ca9d96eb5e5afb Mon Sep 17 00:00:00 2001
   2 From: popcornmix <popcornmix@gmail.com>
   3 Date: Tue, 23 Feb 2016 19:56:04 +0000
   4 Subject: [PATCH] bcm2835-virtgpio: Virtual GPIO driver
   5
   6 Add a virtual GPIO driver that uses the firmware mailbox interface to
   7 request that the VPU toggles LEDs.
   8 ---
   9  drivers/gpio/Kconfig         |   6 +
  10  drivers/gpio/Makefile        |   1 +
  11  drivers/gpio/gpio-bcm-virt.c | 214 +++++++++++++++++++++++++++++++++++
  12  3 files changed, 221 insertions(+)
  13  create mode 100644 drivers/gpio/gpio-bcm-virt.c
  14
  15 --- a/drivers/gpio/Kconfig
  16 +++ b/drivers/gpio/Kconfig
  17 @@ -194,6 +194,12 @@ config GPIO_BCM_XGS_IPROC
  18         help
  19           Say yes here to enable GPIO support for Broadcom XGS iProc SoCs.
  20
  21 +config GPIO_BCM_VIRT
  22 +       bool "Broadcom Virt GPIO"
  23 +       depends on OF_GPIO && RASPBERRYPI_FIRMWARE && (ARCH_BCM2835 || COMPILE_TEST)
  24 +       help
  25 +         Turn on virtual GPIO support for Broadcom BCM283X chips.
  26 +
  27  config GPIO_BRCMSTB
  28         tristate "BRCMSTB GPIO support"
  29         default y if (ARCH_BRCMSTB || BMIPS_GENERIC)
  30 --- a/drivers/gpio/Makefile
  31 +++ b/drivers/gpio/Makefile
  32 @@ -38,6 +38,7 @@ obj-$(CONFIG_GPIO_ASPEED_SGPIO)               += gpio
  33  obj-$(CONFIG_GPIO_ATH79)               += gpio-ath79.o
  34  obj-$(CONFIG_GPIO_BCM_KONA)            += gpio-bcm-kona.o
  35  obj-$(CONFIG_GPIO_BCM_XGS_IPROC)       += gpio-xgs-iproc.o
  36 +obj-$(CONFIG_GPIO_BCM_VIRT)            += gpio-bcm-virt.o
  37  obj-$(CONFIG_GPIO_BD70528)             += gpio-bd70528.o
  38  obj-$(CONFIG_GPIO_BD71815)             += gpio-bd71815.o
  39  obj-$(CONFIG_GPIO_BD71828)             += gpio-bd71828.o
  40 --- /dev/null
  41 +++ b/drivers/gpio/gpio-bcm-virt.c
  42 @@ -0,0 +1,214 @@
  43 +/*
  44 + *  brcmvirt GPIO driver
  45 + *
  46 + *  Copyright (C) 2012,2013 Dom Cobley <popcornmix@gmail.com>
  47 + *  Based on gpio-clps711x.c by Alexander Shiyan <shc_work@mail.ru>
  48 + *
  49 + * This program is free software; you can redistribute it and/or modify
  50 + * it under the terms of the GNU General Public License as published by
  51 + * the Free Software Foundation; either version 2 of the License, or
  52 + * (at your option) any later version.
  53 + */
  54 +
  55 +#include <linux/err.h>
  56 +#include <linux/gpio.h>
  57 +#include <linux/module.h>
  58 +#include <linux/platform_device.h>
  59 +#include <linux/dma-mapping.h>
  60 +#include <soc/bcm2835/raspberrypi-firmware.h>
  61 +
  62 +#define MODULE_NAME "brcmvirt-gpio"
  63 +#define NUM_GPIO 2
  64 +
  65 +struct brcmvirt_gpio {
  66 +       struct gpio_chip        gc;
  67 +       u32 __iomem             *ts_base;
  68 +       /* two packed 16-bit counts of enabled and disables
  69 +           Allows host to detect a brief enable that was missed */
  70 +       u32                     enables_disables[NUM_GPIO];
  71 +       dma_addr_t              bus_addr;
  72 +};
  73 +
  74 +static int brcmvirt_gpio_dir_in(struct gpio_chip *gc, unsigned off)
  75 +{
  76 +       struct brcmvirt_gpio *gpio;
  77 +       gpio = container_of(gc, struct brcmvirt_gpio, gc);
  78 +       return -EINVAL;
  79 +}
  80 +
  81 +static int brcmvirt_gpio_dir_out(struct gpio_chip *gc, unsigned off, int val)
  82 +{
  83 +       struct brcmvirt_gpio *gpio;
  84 +       gpio = container_of(gc, struct brcmvirt_gpio, gc);
  85 +       return 0;
  86 +}
  87 +
  88 +static int brcmvirt_gpio_get(struct gpio_chip *gc, unsigned off)
  89 +{
  90 +       struct brcmvirt_gpio *gpio;
  91 +       unsigned v;
  92 +       gpio = container_of(gc, struct brcmvirt_gpio, gc);
  93 +       v = readl(gpio->ts_base + off);
  94 +       return (v >> off) & 1;
  95 +}
  96 +
  97 +static void brcmvirt_gpio_set(struct gpio_chip *gc, unsigned off, int val)
  98 +{
  99 +       struct brcmvirt_gpio *gpio;
 100 +       u16 enables, disables;
 101 +       s16 diff;
 102 +       bool lit;
 103 +       gpio = container_of(gc, struct brcmvirt_gpio, gc);
 104 +       enables  = gpio->enables_disables[off] >> 16;
 105 +       disables = gpio->enables_disables[off] >>  0;
 106 +       diff = (s16)(enables - disables);
 107 +       lit = diff > 0;
 108 +       if ((val && lit) || (!val && !lit))
 109 +               return;
 110 +       if (val)
 111 +               enables++;
 112 +       else
 113 +               disables++;
 114 +       diff = (s16)(enables - disables);
 115 +       BUG_ON(diff != 0 && diff != 1);
 116 +       gpio->enables_disables[off] = (enables << 16) | (disables << 0);
 117 +       writel(gpio->enables_disables[off], gpio->ts_base + off);
 118 +}
 119 +
 120 +static int brcmvirt_gpio_probe(struct platform_device *pdev)
 121 +{
 122 +       int err = 0;
 123 +       struct device *dev = &pdev->dev;
 124 +       struct device_node *np = dev->of_node;
 125 +       struct device_node *fw_node;
 126 +       struct rpi_firmware *fw;
 127 +       struct brcmvirt_gpio *ucb;
 128 +       u32 gpiovirtbuf;
 129 +
 130 +       fw_node = of_parse_phandle(np, "firmware", 0);
 131 +       if (!fw_node) {
 132 +               dev_err(dev, "Missing firmware node\n");
 133 +               return -ENOENT;
 134 +       }
 135 +
 136 +       fw = rpi_firmware_get(fw_node);
 137 +       if (!fw)
 138 +               return -EPROBE_DEFER;
 139 +
 140 +       ucb = devm_kzalloc(dev, sizeof *ucb, GFP_KERNEL);
 141 +       if (!ucb) {
 142 +               err = -EINVAL;
 143 +               goto out;
 144 +       }
 145 +
 146 +       ucb->ts_base = dma_alloc_coherent(dev, PAGE_SIZE, &ucb->bus_addr, GFP_KERNEL);
 147 +       if (!ucb->ts_base) {
 148 +               pr_err("[%s]: failed to dma_alloc_coherent(%ld)\n",
 149 +                               __func__, PAGE_SIZE);
 150 +               err = -ENOMEM;
 151 +               goto out;
 152 +       }
 153 +
 154 +       gpiovirtbuf = (u32)ucb->bus_addr;
 155 +       err = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_GPIOVIRTBUF,
 156 +                                   &gpiovirtbuf, sizeof(gpiovirtbuf));
 157 +
 158 +       if (err || gpiovirtbuf != 0) {
 159 +               dev_warn(dev, "Failed to set gpiovirtbuf, trying to get err:%x\n", err);
 160 +               dma_free_coherent(dev, PAGE_SIZE, ucb->ts_base, ucb->bus_addr);
 161 +               ucb->ts_base = 0;
 162 +               ucb->bus_addr = 0;
 163 +       }
 164 +
 165 +       if (!ucb->ts_base) {
 166 +               err = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_GET_GPIOVIRTBUF,
 167 +                                           &gpiovirtbuf, sizeof(gpiovirtbuf));
 168 +
 169 +               if (err) {
 170 +                       dev_err(dev, "Failed to get gpiovirtbuf\n");
 171 +                       goto out;
 172 +               }
 173 +
 174 +               if (!gpiovirtbuf) {
 175 +                       dev_err(dev, "No virtgpio buffer\n");
 176 +                       err = -ENOENT;
 177 +                       goto out;
 178 +               }
 179 +
 180 +               // mmap the physical memory
 181 +               gpiovirtbuf &= ~0xc0000000;
 182 +               ucb->ts_base = ioremap(gpiovirtbuf, 4096);
 183 +               if (ucb->ts_base == NULL) {
 184 +                       dev_err(dev, "Failed to map physical address\n");
 185 +                       err = -ENOENT;
 186 +                       goto out;
 187 +               }
 188 +               ucb->bus_addr = 0;
 189 +       }
 190 +       ucb->gc.label = MODULE_NAME;
 191 +       ucb->gc.owner = THIS_MODULE;
 192 +       //ucb->gc.dev = dev;
 193 +       ucb->gc.of_node = np;
 194 +       ucb->gc.base = 100;
 195 +       ucb->gc.ngpio = NUM_GPIO;
 196 +
 197 +       ucb->gc.direction_input = brcmvirt_gpio_dir_in;
 198 +       ucb->gc.direction_output = brcmvirt_gpio_dir_out;
 199 +       ucb->gc.get = brcmvirt_gpio_get;
 200 +       ucb->gc.set = brcmvirt_gpio_set;
 201 +       ucb->gc.can_sleep = true;
 202 +
 203 +       err = gpiochip_add(&ucb->gc);
 204 +       if (err)
 205 +               goto out;
 206 +
 207 +       platform_set_drvdata(pdev, ucb);
 208 +
 209 +       return 0;
 210 +out:
 211 +       if (ucb->bus_addr) {
 212 +               dma_free_coherent(dev, PAGE_SIZE, ucb->ts_base, ucb->bus_addr);
 213 +               ucb->bus_addr = 0;
 214 +               ucb->ts_base = NULL;
 215 +       } else if (ucb->ts_base) {
 216 +               iounmap(ucb->ts_base);
 217 +               ucb->ts_base = NULL;
 218 +       }
 219 +       return err;
 220 +}
 221 +
 222 +static int brcmvirt_gpio_remove(struct platform_device *pdev)
 223 +{
 224 +       struct device *dev = &pdev->dev;
 225 +       int err = 0;
 226 +       struct brcmvirt_gpio *ucb = platform_get_drvdata(pdev);
 227 +
 228 +       gpiochip_remove(&ucb->gc);
 229 +       if (ucb->bus_addr)
 230 +               dma_free_coherent(dev, PAGE_SIZE, ucb->ts_base, ucb->bus_addr);
 231 +       else if (ucb->ts_base)
 232 +               iounmap(ucb->ts_base);
 233 +       return err;
 234 +}
 235 +
 236 +static const struct of_device_id __maybe_unused brcmvirt_gpio_ids[] = {
 237 +       { .compatible = "brcm,bcm2835-virtgpio" },
 238 +       { }
 239 +};
 240 +MODULE_DEVICE_TABLE(of, brcmvirt_gpio_ids);
 241 +
 242 +static struct platform_driver brcmvirt_gpio_driver = {
 243 +       .driver = {
 244 +               .name           = MODULE_NAME,
 245 +               .owner          = THIS_MODULE,
 246 +               .of_match_table = of_match_ptr(brcmvirt_gpio_ids),
 247 +       },
 248 +       .probe  = brcmvirt_gpio_probe,
 249 +       .remove = brcmvirt_gpio_remove,
 250 +};
 251 +module_platform_driver(brcmvirt_gpio_driver);
 252 +
 253 +MODULE_LICENSE("GPL");
 254 +MODULE_AUTHOR("Dom Cobley <popcornmix@gmail.com>");
 255 +MODULE_DESCRIPTION("brcmvirt GPIO driver");
 256 +MODULE_ALIAS("platform:brcmvirt-gpio");