![Gustavo A. R. Silva](/assets/img/avatar_default.png)
One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct led_pwm_priv { ... struct led_pwm_data leds[0]; }; Make use of the struct_size() helper instead of an open-coded version in order to avoid any potential type mistakes. So, replace the following function: static inline size_t sizeof_pwm_leds_priv(int num_leds) { return sizeof(struct led_pwm_priv) + (sizeof(struct led_pwm_data) * num_leds); } with: struct_size(priv, leds, count) This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
215 lines
4.7 KiB
C
215 lines
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/drivers/leds-pwm.c
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*
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* simple PWM based LED control
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*
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* Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
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*
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* based on leds-gpio.c by Raphael Assenat <raph@8d.com>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/of_platform.h>
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#include <linux/leds.h>
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#include <linux/err.h>
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#include <linux/pwm.h>
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#include <linux/leds_pwm.h>
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#include <linux/slab.h>
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struct led_pwm_data {
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struct led_classdev cdev;
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struct pwm_device *pwm;
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unsigned int active_low;
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unsigned int period;
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int duty;
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};
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struct led_pwm_priv {
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int num_leds;
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struct led_pwm_data leds[0];
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};
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static void __led_pwm_set(struct led_pwm_data *led_dat)
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{
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int new_duty = led_dat->duty;
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pwm_config(led_dat->pwm, new_duty, led_dat->period);
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if (new_duty == 0)
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pwm_disable(led_dat->pwm);
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else
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pwm_enable(led_dat->pwm);
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}
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static int led_pwm_set(struct led_classdev *led_cdev,
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enum led_brightness brightness)
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{
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struct led_pwm_data *led_dat =
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container_of(led_cdev, struct led_pwm_data, cdev);
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unsigned int max = led_dat->cdev.max_brightness;
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unsigned long long duty = led_dat->period;
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duty *= brightness;
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do_div(duty, max);
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if (led_dat->active_low)
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duty = led_dat->period - duty;
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led_dat->duty = duty;
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__led_pwm_set(led_dat);
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return 0;
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}
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static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
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struct led_pwm *led, struct fwnode_handle *fwnode)
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{
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struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
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struct pwm_args pargs;
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int ret;
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led_data->active_low = led->active_low;
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led_data->cdev.name = led->name;
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led_data->cdev.default_trigger = led->default_trigger;
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led_data->cdev.brightness = LED_OFF;
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led_data->cdev.max_brightness = led->max_brightness;
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led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
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if (fwnode)
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led_data->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);
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else
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led_data->pwm = devm_pwm_get(dev, led->name);
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if (IS_ERR(led_data->pwm)) {
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ret = PTR_ERR(led_data->pwm);
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if (ret != -EPROBE_DEFER)
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dev_err(dev, "unable to request PWM for %s: %d\n",
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led->name, ret);
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return ret;
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}
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led_data->cdev.brightness_set_blocking = led_pwm_set;
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/*
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* FIXME: pwm_apply_args() should be removed when switching to the
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* atomic PWM API.
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*/
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pwm_apply_args(led_data->pwm);
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pwm_get_args(led_data->pwm, &pargs);
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led_data->period = pargs.period;
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if (!led_data->period && (led->pwm_period_ns > 0))
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led_data->period = led->pwm_period_ns;
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ret = devm_led_classdev_register(dev, &led_data->cdev);
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if (ret == 0) {
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priv->num_leds++;
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led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
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} else {
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dev_err(dev, "failed to register PWM led for %s: %d\n",
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led->name, ret);
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}
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return ret;
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}
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static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv)
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{
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struct fwnode_handle *fwnode;
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struct led_pwm led;
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int ret = 0;
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memset(&led, 0, sizeof(led));
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device_for_each_child_node(dev, fwnode) {
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ret = fwnode_property_read_string(fwnode, "label", &led.name);
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if (ret && is_of_node(fwnode))
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led.name = to_of_node(fwnode)->name;
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if (!led.name) {
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fwnode_handle_put(fwnode);
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return -EINVAL;
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}
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fwnode_property_read_string(fwnode, "linux,default-trigger",
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&led.default_trigger);
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led.active_low = fwnode_property_read_bool(fwnode,
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"active-low");
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fwnode_property_read_u32(fwnode, "max-brightness",
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&led.max_brightness);
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ret = led_pwm_add(dev, priv, &led, fwnode);
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if (ret) {
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fwnode_handle_put(fwnode);
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break;
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}
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}
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return ret;
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}
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static int led_pwm_probe(struct platform_device *pdev)
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{
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struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
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struct led_pwm_priv *priv;
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int count, i;
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int ret = 0;
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if (pdata)
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count = pdata->num_leds;
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else
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count = device_get_child_node_count(&pdev->dev);
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if (!count)
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return -EINVAL;
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priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),
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GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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if (pdata) {
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for (i = 0; i < count; i++) {
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ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
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NULL);
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if (ret)
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break;
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}
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} else {
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ret = led_pwm_create_fwnode(&pdev->dev, priv);
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}
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if (ret)
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return ret;
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platform_set_drvdata(pdev, priv);
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return 0;
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}
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static const struct of_device_id of_pwm_leds_match[] = {
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{ .compatible = "pwm-leds", },
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{},
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};
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MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
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static struct platform_driver led_pwm_driver = {
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.probe = led_pwm_probe,
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.driver = {
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.name = "leds_pwm",
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.of_match_table = of_pwm_leds_match,
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},
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};
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module_platform_driver(led_pwm_driver);
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MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
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MODULE_DESCRIPTION("generic PWM LED driver");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:leds-pwm");
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