257 lines
7.1 KiB
Diff
257 lines
7.1 KiB
Diff
From f82deda879262289568dec22dd43ecc10c265fb6 Mon Sep 17 00:00:00 2001
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From: popcornmix <popcornmix@gmail.com>
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Date: Tue, 23 Feb 2016 19:56:04 +0000
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Subject: [PATCH] bcm2835-virtgpio: Virtual GPIO driver
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Add a virtual GPIO driver that uses the firmware mailbox interface to
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request that the VPU toggles LEDs.
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---
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drivers/gpio/Kconfig | 6 +
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drivers/gpio/Makefile | 1 +
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drivers/gpio/gpio-bcm-virt.c | 214 +++++++++++++++++++++++++++++++++++
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3 files changed, 221 insertions(+)
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create mode 100644 drivers/gpio/gpio-bcm-virt.c
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--- a/drivers/gpio/Kconfig
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+++ b/drivers/gpio/Kconfig
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@@ -193,6 +193,12 @@ config GPIO_BCM_XGS_IPROC
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help
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Say yes here to enable GPIO support for Broadcom XGS iProc SoCs.
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+config GPIO_BCM_VIRT
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+ bool "Broadcom Virt GPIO"
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+ depends on OF_GPIO && RASPBERRYPI_FIRMWARE && (ARCH_BCM2835 || COMPILE_TEST)
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+ help
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+ Turn on virtual GPIO support for Broadcom BCM283X chips.
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+
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config GPIO_BRCMSTB
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tristate "BRCMSTB GPIO support"
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default y if (ARCH_BRCMSTB || BMIPS_GENERIC)
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--- a/drivers/gpio/Makefile
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+++ b/drivers/gpio/Makefile
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@@ -38,6 +38,7 @@ obj-$(CONFIG_GPIO_ASPEED_SGPIO) += gpio
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obj-$(CONFIG_GPIO_ATH79) += gpio-ath79.o
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obj-$(CONFIG_GPIO_BCM_KONA) += gpio-bcm-kona.o
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obj-$(CONFIG_GPIO_BCM_XGS_IPROC) += gpio-xgs-iproc.o
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+obj-$(CONFIG_GPIO_BCM_VIRT) += gpio-bcm-virt.o
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obj-$(CONFIG_GPIO_BD70528) += gpio-bd70528.o
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obj-$(CONFIG_GPIO_BD71828) += gpio-bd71828.o
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obj-$(CONFIG_GPIO_BD9571MWV) += gpio-bd9571mwv.o
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--- /dev/null
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+++ b/drivers/gpio/gpio-bcm-virt.c
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@@ -0,0 +1,214 @@
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+/*
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+ * brcmvirt GPIO driver
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+ *
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+ * Copyright (C) 2012,2013 Dom Cobley <popcornmix@gmail.com>
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+ * Based on gpio-clps711x.c by Alexander Shiyan <shc_work@mail.ru>
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License as published by
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+ * the Free Software Foundation; either version 2 of the License, or
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+ * (at your option) any later version.
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+ */
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+
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+#include <linux/err.h>
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+#include <linux/gpio.h>
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+#include <linux/module.h>
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+#include <linux/platform_device.h>
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+#include <linux/dma-mapping.h>
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+#include <soc/bcm2835/raspberrypi-firmware.h>
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+
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+#define MODULE_NAME "brcmvirt-gpio"
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+#define NUM_GPIO 2
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+
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+struct brcmvirt_gpio {
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+ struct gpio_chip gc;
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+ u32 __iomem *ts_base;
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+ /* two packed 16-bit counts of enabled and disables
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+ Allows host to detect a brief enable that was missed */
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+ u32 enables_disables[NUM_GPIO];
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+ dma_addr_t bus_addr;
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+};
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+
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+static int brcmvirt_gpio_dir_in(struct gpio_chip *gc, unsigned off)
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+{
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+ struct brcmvirt_gpio *gpio;
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+ gpio = container_of(gc, struct brcmvirt_gpio, gc);
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+ return -EINVAL;
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+}
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+
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+static int brcmvirt_gpio_dir_out(struct gpio_chip *gc, unsigned off, int val)
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+{
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+ struct brcmvirt_gpio *gpio;
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+ gpio = container_of(gc, struct brcmvirt_gpio, gc);
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+ return 0;
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+}
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+
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+static int brcmvirt_gpio_get(struct gpio_chip *gc, unsigned off)
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+{
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+ struct brcmvirt_gpio *gpio;
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+ unsigned v;
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+ gpio = container_of(gc, struct brcmvirt_gpio, gc);
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+ v = readl(gpio->ts_base + off);
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+ return (v >> off) & 1;
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+}
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+
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+static void brcmvirt_gpio_set(struct gpio_chip *gc, unsigned off, int val)
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+{
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+ struct brcmvirt_gpio *gpio;
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+ u16 enables, disables;
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+ s16 diff;
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+ bool lit;
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+ gpio = container_of(gc, struct brcmvirt_gpio, gc);
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+ enables = gpio->enables_disables[off] >> 16;
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+ disables = gpio->enables_disables[off] >> 0;
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+ diff = (s16)(enables - disables);
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+ lit = diff > 0;
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+ if ((val && lit) || (!val && !lit))
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+ return;
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+ if (val)
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+ enables++;
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+ else
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+ disables++;
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+ diff = (s16)(enables - disables);
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+ BUG_ON(diff != 0 && diff != 1);
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+ gpio->enables_disables[off] = (enables << 16) | (disables << 0);
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+ writel(gpio->enables_disables[off], gpio->ts_base + off);
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+}
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+
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+static int brcmvirt_gpio_probe(struct platform_device *pdev)
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+{
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+ int err = 0;
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+ struct device *dev = &pdev->dev;
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+ struct device_node *np = dev->of_node;
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+ struct device_node *fw_node;
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+ struct rpi_firmware *fw;
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+ struct brcmvirt_gpio *ucb;
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+ u32 gpiovirtbuf;
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+
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+ fw_node = of_parse_phandle(np, "firmware", 0);
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+ if (!fw_node) {
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+ dev_err(dev, "Missing firmware node\n");
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+ return -ENOENT;
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+ }
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+
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+ fw = rpi_firmware_get(fw_node);
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+ if (!fw)
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+ return -EPROBE_DEFER;
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+
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+ ucb = devm_kzalloc(dev, sizeof *ucb, GFP_KERNEL);
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+ if (!ucb) {
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+ err = -EINVAL;
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+ goto out;
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+ }
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+
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+ ucb->ts_base = dma_alloc_coherent(dev, PAGE_SIZE, &ucb->bus_addr, GFP_KERNEL);
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+ if (!ucb->ts_base) {
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+ pr_err("[%s]: failed to dma_alloc_coherent(%ld)\n",
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+ __func__, PAGE_SIZE);
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+ err = -ENOMEM;
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+ goto out;
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+ }
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+
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+ gpiovirtbuf = (u32)ucb->bus_addr;
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+ err = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_GPIOVIRTBUF,
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+ &gpiovirtbuf, sizeof(gpiovirtbuf));
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+
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+ if (err || gpiovirtbuf != 0) {
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+ dev_warn(dev, "Failed to set gpiovirtbuf, trying to get err:%x\n", err);
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+ dma_free_coherent(dev, PAGE_SIZE, ucb->ts_base, ucb->bus_addr);
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+ ucb->ts_base = 0;
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+ ucb->bus_addr = 0;
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+ }
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+
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+ if (!ucb->ts_base) {
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+ err = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_GET_GPIOVIRTBUF,
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+ &gpiovirtbuf, sizeof(gpiovirtbuf));
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+
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+ if (err) {
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+ dev_err(dev, "Failed to get gpiovirtbuf\n");
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+ goto out;
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+ }
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+
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+ if (!gpiovirtbuf) {
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+ dev_err(dev, "No virtgpio buffer\n");
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+ err = -ENOENT;
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+ goto out;
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+ }
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+
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+ // mmap the physical memory
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+ gpiovirtbuf &= ~0xc0000000;
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+ ucb->ts_base = ioremap(gpiovirtbuf, 4096);
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+ if (ucb->ts_base == NULL) {
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+ dev_err(dev, "Failed to map physical address\n");
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+ err = -ENOENT;
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+ goto out;
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+ }
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+ ucb->bus_addr = 0;
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+ }
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+ ucb->gc.label = MODULE_NAME;
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+ ucb->gc.owner = THIS_MODULE;
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+ //ucb->gc.dev = dev;
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+ ucb->gc.of_node = np;
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+ ucb->gc.base = 100;
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+ ucb->gc.ngpio = NUM_GPIO;
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+
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+ ucb->gc.direction_input = brcmvirt_gpio_dir_in;
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+ ucb->gc.direction_output = brcmvirt_gpio_dir_out;
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+ ucb->gc.get = brcmvirt_gpio_get;
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+ ucb->gc.set = brcmvirt_gpio_set;
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+ ucb->gc.can_sleep = true;
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+
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+ err = gpiochip_add(&ucb->gc);
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+ if (err)
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+ goto out;
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+
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+ platform_set_drvdata(pdev, ucb);
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+
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+ return 0;
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+out:
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+ if (ucb->bus_addr) {
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+ dma_free_coherent(dev, PAGE_SIZE, ucb->ts_base, ucb->bus_addr);
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+ ucb->bus_addr = 0;
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+ ucb->ts_base = NULL;
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+ } else if (ucb->ts_base) {
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+ iounmap(ucb->ts_base);
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+ ucb->ts_base = NULL;
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+ }
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+ return err;
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+}
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+
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+static int brcmvirt_gpio_remove(struct platform_device *pdev)
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+{
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+ struct device *dev = &pdev->dev;
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+ int err = 0;
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+ struct brcmvirt_gpio *ucb = platform_get_drvdata(pdev);
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+
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+ gpiochip_remove(&ucb->gc);
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+ if (ucb->bus_addr)
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+ dma_free_coherent(dev, PAGE_SIZE, ucb->ts_base, ucb->bus_addr);
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+ else if (ucb->ts_base)
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+ iounmap(ucb->ts_base);
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+ return err;
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+}
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+
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+static const struct of_device_id __maybe_unused brcmvirt_gpio_ids[] = {
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+ { .compatible = "brcm,bcm2835-virtgpio" },
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+ { }
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+};
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+MODULE_DEVICE_TABLE(of, brcmvirt_gpio_ids);
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+
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+static struct platform_driver brcmvirt_gpio_driver = {
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+ .driver = {
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+ .name = MODULE_NAME,
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+ .owner = THIS_MODULE,
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+ .of_match_table = of_match_ptr(brcmvirt_gpio_ids),
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+ },
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+ .probe = brcmvirt_gpio_probe,
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+ .remove = brcmvirt_gpio_remove,
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+};
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+module_platform_driver(brcmvirt_gpio_driver);
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+
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+MODULE_LICENSE("GPL");
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+MODULE_AUTHOR("Dom Cobley <popcornmix@gmail.com>");
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+MODULE_DESCRIPTION("brcmvirt GPIO driver");
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+MODULE_ALIAS("platform:brcmvirt-gpio");
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