594fa265e0
Currently the kernel uses the struct device_node.data pointer to resolve a struct gpio_chip pointer from a device tree node. However, the .data member doesn't provide any type checking and there aren't any rules enforced on what it should be used for. There's no guarantee that the data stored in it actually points to an gpio_chip pointer. Instead of relying on the .data pointer, this patch modifies the code to add a lookup function which scans through the registered gpio_chips and returns the gpio_chip that has a pointer to the specified device_node. Signed-off-by: Grant Likely <grant.likely@secretlab.ca> CC: Andrew Morton <akpm@linux-foundation.org> CC: Anton Vorontsov <avorontsov@ru.mvista.com> CC: Grant Likely <grant.likely@secretlab.ca> CC: David Brownell <dbrownell@users.sourceforge.net> CC: Bill Gatliff <bgat@billgatliff.com> CC: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: Jean Delvare <khali@linux-fr.org> CC: linux-kernel@vger.kernel.org CC: devicetree-discuss@lists.ozlabs.org
141 lines
2.8 KiB
C
141 lines
2.8 KiB
C
/*
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* Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2009 PetaLogix
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/init.h>
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#include <linux/of_platform.h>
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#include <asm/prom.h>
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/* Trigger specific functions */
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#ifdef CONFIG_GPIOLIB
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#include <linux/of_gpio.h>
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static int handle; /* reset pin handle */
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static unsigned int reset_val;
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static int of_reset_gpio_handle(void)
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{
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int ret; /* variable which stored handle reset gpio pin */
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struct device_node *root; /* root node */
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struct device_node *gpio; /* gpio node */
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struct gpio_chip *gc;
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u32 flags;
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const void *gpio_spec;
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/* find out root node */
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root = of_find_node_by_path("/");
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/* give me handle for gpio node to be possible allocate pin */
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ret = of_parse_phandles_with_args(root, "hard-reset-gpios",
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"#gpio-cells", 0, &gpio, &gpio_spec);
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if (ret) {
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pr_debug("%s: can't parse gpios property\n", __func__);
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goto err0;
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}
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gc = of_node_to_gpiochip(gpio);
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if (!gc) {
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pr_debug("%s: gpio controller %s isn't registered\n",
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root->full_name, gpio->full_name);
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ret = -ENODEV;
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goto err1;
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}
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ret = gc->of_xlate(gc, root, gpio_spec, &flags);
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if (ret < 0)
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goto err1;
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ret += gc->base;
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err1:
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of_node_put(gpio);
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err0:
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pr_debug("%s exited with status %d\n", __func__, ret);
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return ret;
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}
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void of_platform_reset_gpio_probe(void)
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{
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int ret;
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handle = of_reset_gpio_handle();
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if (!gpio_is_valid(handle)) {
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printk(KERN_INFO "Skipping unavailable RESET gpio %d (%s)\n",
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handle, "reset");
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}
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ret = gpio_request(handle, "reset");
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if (ret < 0) {
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printk(KERN_INFO "GPIO pin is already allocated\n");
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return;
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}
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/* get current setup value */
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reset_val = gpio_get_value(handle);
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/* FIXME maybe worth to perform any action */
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pr_debug("Reset: Gpio output state: 0x%x\n", reset_val);
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/* Setup GPIO as output */
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ret = gpio_direction_output(handle, 0);
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if (ret < 0)
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goto err;
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/* Setup output direction */
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gpio_set_value(handle, 0);
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printk(KERN_INFO "RESET: Registered gpio device: %d, current val: %d\n",
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handle, reset_val);
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return;
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err:
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gpio_free(handle);
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return;
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}
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static void gpio_system_reset(void)
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{
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gpio_set_value(handle, 1 - reset_val);
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}
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#else
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#define gpio_system_reset() do {} while (0)
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void of_platform_reset_gpio_probe(void)
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{
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return;
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}
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#endif
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void machine_restart(char *cmd)
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{
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printk(KERN_NOTICE "Machine restart...\n");
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gpio_system_reset();
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dump_stack();
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while (1)
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;
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}
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void machine_shutdown(void)
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{
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printk(KERN_NOTICE "Machine shutdown...\n");
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while (1)
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;
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}
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void machine_halt(void)
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{
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printk(KERN_NOTICE "Machine halt...\n");
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while (1)
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;
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}
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void machine_power_off(void)
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{
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printk(KERN_NOTICE "Machine power off...\n");
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while (1)
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;
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}
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