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![Gregory Fong](/assets/img/avatar_default.png)
If a failure occurs during probe, brcmstb_gpio_remove() is called. In remove, we call platform_get_drvdata(), but at the time of failure in the probe the driver data hadn't yet been set which leads to a NULL ptr dereference in the remove's list_for_each. Call platform_set_drvdata() and set up list head right after allocating the priv struct to both avoid the null pointer dereference that could occur today. To guard against potential future changes, check for null pointer in remove. Reported-by: Tim Ross <tross@broadcom.com> Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
260 lines
6.8 KiB
C
260 lines
6.8 KiB
C
/*
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* Copyright (C) 2015 Broadcom Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation version 2.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/bitops.h>
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#include <linux/gpio/driver.h>
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#include <linux/of_device.h>
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#include <linux/of_irq.h>
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#include <linux/module.h>
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#include <linux/basic_mmio_gpio.h>
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#define GIO_BANK_SIZE 0x20
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#define GIO_ODEN(bank) (((bank) * GIO_BANK_SIZE) + 0x00)
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#define GIO_DATA(bank) (((bank) * GIO_BANK_SIZE) + 0x04)
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#define GIO_IODIR(bank) (((bank) * GIO_BANK_SIZE) + 0x08)
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#define GIO_EC(bank) (((bank) * GIO_BANK_SIZE) + 0x0c)
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#define GIO_EI(bank) (((bank) * GIO_BANK_SIZE) + 0x10)
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#define GIO_MASK(bank) (((bank) * GIO_BANK_SIZE) + 0x14)
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#define GIO_LEVEL(bank) (((bank) * GIO_BANK_SIZE) + 0x18)
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#define GIO_STAT(bank) (((bank) * GIO_BANK_SIZE) + 0x1c)
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struct brcmstb_gpio_bank {
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struct list_head node;
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int id;
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struct bgpio_chip bgc;
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struct brcmstb_gpio_priv *parent_priv;
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u32 width;
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};
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struct brcmstb_gpio_priv {
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struct list_head bank_list;
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void __iomem *reg_base;
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int num_banks;
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struct platform_device *pdev;
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int gpio_base;
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};
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#define MAX_GPIO_PER_BANK 32
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#define GPIO_BANK(gpio) ((gpio) >> 5)
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/* assumes MAX_GPIO_PER_BANK is a multiple of 2 */
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#define GPIO_BIT(gpio) ((gpio) & (MAX_GPIO_PER_BANK - 1))
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static inline struct brcmstb_gpio_bank *
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brcmstb_gpio_gc_to_bank(struct gpio_chip *gc)
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{
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struct bgpio_chip *bgc = to_bgpio_chip(gc);
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return container_of(bgc, struct brcmstb_gpio_bank, bgc);
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}
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static inline struct brcmstb_gpio_priv *
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brcmstb_gpio_gc_to_priv(struct gpio_chip *gc)
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{
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struct brcmstb_gpio_bank *bank = brcmstb_gpio_gc_to_bank(gc);
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return bank->parent_priv;
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}
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/* Make sure that the number of banks matches up between properties */
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static int brcmstb_gpio_sanity_check_banks(struct device *dev,
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struct device_node *np, struct resource *res)
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{
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int res_num_banks = resource_size(res) / GIO_BANK_SIZE;
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int num_banks =
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of_property_count_u32_elems(np, "brcm,gpio-bank-widths");
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if (res_num_banks != num_banks) {
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dev_err(dev, "Mismatch in banks: res had %d, bank-widths had %d\n",
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res_num_banks, num_banks);
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return -EINVAL;
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} else {
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return 0;
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}
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}
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static int brcmstb_gpio_remove(struct platform_device *pdev)
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{
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struct brcmstb_gpio_priv *priv = platform_get_drvdata(pdev);
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struct list_head *pos;
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struct brcmstb_gpio_bank *bank;
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int ret = 0;
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if (!priv) {
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dev_err(&pdev->dev, "called %s without drvdata!\n", __func__);
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return -EFAULT;
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}
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/*
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* You can lose return values below, but we report all errors, and it's
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* more important to actually perform all of the steps.
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*/
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list_for_each(pos, &priv->bank_list) {
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bank = list_entry(pos, struct brcmstb_gpio_bank, node);
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ret = bgpio_remove(&bank->bgc);
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if (ret)
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dev_err(&pdev->dev, "gpiochip_remove fail in cleanup");
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}
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return ret;
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}
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static int brcmstb_gpio_of_xlate(struct gpio_chip *gc,
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const struct of_phandle_args *gpiospec, u32 *flags)
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{
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struct brcmstb_gpio_priv *priv = brcmstb_gpio_gc_to_priv(gc);
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struct brcmstb_gpio_bank *bank = brcmstb_gpio_gc_to_bank(gc);
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int offset;
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if (gc->of_gpio_n_cells != 2) {
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WARN_ON(1);
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return -EINVAL;
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}
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if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
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return -EINVAL;
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offset = gpiospec->args[0] - (gc->base - priv->gpio_base);
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if (offset >= gc->ngpio)
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return -EINVAL;
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if (unlikely(offset >= bank->width)) {
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dev_warn_ratelimited(&priv->pdev->dev,
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"Received request for invalid GPIO offset %d\n",
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gpiospec->args[0]);
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}
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if (flags)
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*flags = gpiospec->args[1];
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return offset;
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}
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static int brcmstb_gpio_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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void __iomem *reg_base;
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struct brcmstb_gpio_priv *priv;
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struct resource *res;
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struct property *prop;
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const __be32 *p;
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u32 bank_width;
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int err;
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static int gpio_base;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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platform_set_drvdata(pdev, priv);
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INIT_LIST_HEAD(&priv->bank_list);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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reg_base = devm_ioremap_resource(dev, res);
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if (IS_ERR(reg_base))
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return PTR_ERR(reg_base);
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priv->gpio_base = gpio_base;
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priv->reg_base = reg_base;
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priv->pdev = pdev;
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if (brcmstb_gpio_sanity_check_banks(dev, np, res))
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return -EINVAL;
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of_property_for_each_u32(np, "brcm,gpio-bank-widths", prop, p,
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bank_width) {
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struct brcmstb_gpio_bank *bank;
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struct bgpio_chip *bgc;
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struct gpio_chip *gc;
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bank = devm_kzalloc(dev, sizeof(*bank), GFP_KERNEL);
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if (!bank) {
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err = -ENOMEM;
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goto fail;
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}
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bank->parent_priv = priv;
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bank->id = priv->num_banks;
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if (bank_width <= 0 || bank_width > MAX_GPIO_PER_BANK) {
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dev_err(dev, "Invalid bank width %d\n", bank_width);
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goto fail;
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} else {
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bank->width = bank_width;
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}
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/*
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* Regs are 4 bytes wide, have data reg, no set/clear regs,
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* and direction bits have 0 = output and 1 = input
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*/
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bgc = &bank->bgc;
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err = bgpio_init(bgc, dev, 4,
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reg_base + GIO_DATA(bank->id),
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NULL, NULL, NULL,
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reg_base + GIO_IODIR(bank->id), 0);
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if (err) {
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dev_err(dev, "bgpio_init() failed\n");
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goto fail;
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}
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gc = &bgc->gc;
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gc->of_node = np;
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gc->owner = THIS_MODULE;
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gc->label = np->full_name;
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gc->base = gpio_base;
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gc->of_gpio_n_cells = 2;
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gc->of_xlate = brcmstb_gpio_of_xlate;
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/* not all ngpio lines are valid, will use bank width later */
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gc->ngpio = MAX_GPIO_PER_BANK;
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err = gpiochip_add(gc);
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if (err) {
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dev_err(dev, "Could not add gpiochip for bank %d\n",
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bank->id);
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goto fail;
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}
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gpio_base += gc->ngpio;
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dev_dbg(dev, "bank=%d, base=%d, ngpio=%d, width=%d\n", bank->id,
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gc->base, gc->ngpio, bank->width);
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/* Everything looks good, so add bank to list */
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list_add(&bank->node, &priv->bank_list);
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priv->num_banks++;
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}
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dev_info(dev, "Registered %d banks (GPIO(s): %d-%d)\n",
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priv->num_banks, priv->gpio_base, gpio_base - 1);
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return 0;
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fail:
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(void) brcmstb_gpio_remove(pdev);
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return err;
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}
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static const struct of_device_id brcmstb_gpio_of_match[] = {
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{ .compatible = "brcm,brcmstb-gpio" },
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{},
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};
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MODULE_DEVICE_TABLE(of, brcmstb_gpio_of_match);
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static struct platform_driver brcmstb_gpio_driver = {
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.driver = {
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.name = "brcmstb-gpio",
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.of_match_table = brcmstb_gpio_of_match,
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},
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.probe = brcmstb_gpio_probe,
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.remove = brcmstb_gpio_remove,
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};
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module_platform_driver(brcmstb_gpio_driver);
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MODULE_AUTHOR("Gregory Fong");
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MODULE_DESCRIPTION("Driver for Broadcom BRCMSTB SoC UPG GPIO");
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MODULE_LICENSE("GPL v2");
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