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Subject[PWM PATCH 4/7] Implements PWM-based LED control
Date

Signed-off-by: Bill Gatliff <bgat@billgatliff.com>
---
drivers/leds/leds-pwm.c | 224 ++++++++++++++++++++++++-------------------
include/linux/pwm/pwm-led.h | 33 +++++++
2 files changed, 157 insertions(+), 100 deletions(-)
create mode 100644 include/linux/pwm/pwm-led.h

diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
index 88b1dd0..7877af8 100644
--- a/drivers/leds/leds-pwm.c
+++ b/drivers/leds/leds-pwm.c
@@ -1,152 +1,176 @@
/*
- * linux/drivers/leds-pwm.c
+ * drivers/leds/leds-pwm.c
*
- * simple PWM based LED control
+ * Copyright (C) 2010 Bill Gatliff <bgat@billgatliff.com>
+ * Copyright (C) 2009 Loutao Fu, Pengutronix <l.fu@pengutronix.de>
*
- * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
+ * Based on leds-gpio.c by Raphael Assenat <raph@8d.com>
*
- * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
+ * This program is Free Software. You may redistribute and/or modify
+ * it under the terms of the GNU General Public License version 2, as
* published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
*/
-
-#include <linux/module.h>
#include <linux/kernel.h>
-#include <linux/init.h>
#include <linux/platform_device.h>
-#include <linux/fb.h>
#include <linux/leds.h>
-#include <linux/err.h>
-#include <linux/pwm.h>
-#include <linux/leds_pwm.h>
-
-struct led_pwm_data {
- struct led_classdev cdev;
- struct pwm_device *pwm;
- unsigned int active_low;
- unsigned int period;
+#include <linux/io.h>
+#include <linux/pwm/pwm.h>
+#include <linux/pwm/pwm-led.h>
+
+struct led_pwm {
+ struct led_classdev led;
+ struct pwm_channel *pwm;
+ int percent;
};

-static void led_pwm_set(struct led_classdev *led_cdev,
- enum led_brightness brightness)
+static inline struct led_pwm *to_led_pwm(const struct led_classdev *c)
+{
+ return container_of(c, struct led_pwm, led);
+}
+
+static void
+led_pwm_brightness_set(struct led_classdev *c,
+ enum led_brightness b)
+{
+ struct led_pwm *led = to_led_pwm(c);
+ int percent;
+
+ percent = (b * 100) / (LED_FULL - LED_OFF);
+ led->percent = percent;
+ pwm_set_duty_percent(led->pwm, percent);
+}
+
+static enum led_brightness
+led_pwm_brightness_get(struct led_classdev *c)
+{
+ struct led_pwm *led = to_led_pwm(c);
+ return led->percent;
+}
+
+static int
+led_pwm_blink_set(struct led_classdev *c,
+ unsigned long *on_ms,
+ unsigned long *off_ms)
{
- struct led_pwm_data *led_dat =
- container_of(led_cdev, struct led_pwm_data, cdev);
- unsigned int max = led_dat->cdev.max_brightness;
- unsigned int period = led_dat->period;
-
- if (brightness == 0) {
- pwm_config(led_dat->pwm, 0, period);
- pwm_disable(led_dat->pwm);
- } else {
- pwm_config(led_dat->pwm, brightness * period / max, period);
- pwm_enable(led_dat->pwm);
+ struct led_pwm *led = to_led_pwm(c);
+ struct pwm_channel_config cfg;
+
+ if (*on_ms == 0 && *off_ms == 0) {
+ *on_ms = 1000UL;
+ *off_ms = 1000UL;
}
+
+ cfg.config_mask = PWM_CONFIG_DUTY_NS
+ | PWM_CONFIG_PERIOD_NS;
+
+ cfg.duty_ns = *on_ms * 1000000UL;
+ cfg.period_ns = (*on_ms + *off_ms) * 1000000UL;
+
+ return pwm_config(led->pwm, &cfg);
}

-static int led_pwm_probe(struct platform_device *pdev)
+static int __devinit
+led_pwm_probe(struct platform_device *pdev)
{
- struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
- struct led_pwm *cur_led;
- struct led_pwm_data *leds_data, *led_dat;
- int i, ret = 0;
+ struct pwm_led_platform_data *pdata = pdev->dev.platform_data;
+ struct led_pwm *led;
+ struct device *d = &pdev->dev;
+ int ret;

- if (!pdata)
- return -EBUSY;
+ if (!pdata || !pdata->led_info)
+ return -EINVAL;

- leds_data = kzalloc(sizeof(struct led_pwm_data) * pdata->num_leds,
- GFP_KERNEL);
- if (!leds_data)
+ led = kzalloc(sizeof(*led), GFP_KERNEL);
+ if (!led)
return -ENOMEM;

- for (i = 0; i < pdata->num_leds; i++) {
- cur_led = &pdata->leds[i];
- led_dat = &leds_data[i];
-
- led_dat->pwm = pwm_request(cur_led->pwm_id,
- cur_led->name);
- if (IS_ERR(led_dat->pwm)) {
- dev_err(&pdev->dev, "unable to request PWM %d\n",
- cur_led->pwm_id);
- goto err;
- }
-
- led_dat->cdev.name = cur_led->name;
- led_dat->cdev.default_trigger = cur_led->default_trigger;
- led_dat->active_low = cur_led->active_low;
- led_dat->period = cur_led->pwm_period_ns;
- led_dat->cdev.brightness_set = led_pwm_set;
- led_dat->cdev.brightness = LED_OFF;
- led_dat->cdev.max_brightness = cur_led->max_brightness;
- led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
-
- ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
- if (ret < 0) {
- pwm_free(led_dat->pwm);
- goto err;
- }
+ led->pwm = pwm_request(pdata->bus_id, pdata->chan,
+ pdata->led_info->name);
+ if (!led->pwm) {
+ ret = -EINVAL;
+ goto err_pwm_request;
}

- platform_set_drvdata(pdev, leds_data);
+ platform_set_drvdata(pdev, led);

- return 0;
+ led->led.name = pdata->led_info->name;
+ led->led.default_trigger = pdata->led_info->default_trigger;
+ led->led.brightness_set = led_pwm_brightness_set;
+ led->led.brightness_get = led_pwm_brightness_get;
+ led->led.blink_set = led_pwm_blink_set;
+ led->led.brightness = LED_OFF;

-err:
- if (i > 0) {
- for (i = i - 1; i >= 0; i--) {
- led_classdev_unregister(&leds_data[i].cdev);
- pwm_free(leds_data[i].pwm);
- }
- }
+ ret = pwm_config(led->pwm, pdata->config);
+ if (ret)
+ goto err_pwm_config;
+ pwm_start(led->pwm);
+
+ ret = led_classdev_register(&pdev->dev, &led->led);
+ if (ret < 0)
+ goto err_classdev_register;

- kfree(leds_data);
+ return 0;
+
+err_classdev_register:
+ pwm_stop(led->pwm);
+err_pwm_config:
+ pwm_free(led->pwm);
+err_pwm_request:
+ kfree(led);

return ret;
}

-static int __devexit led_pwm_remove(struct platform_device *pdev)
+static int __devexit
+led_pwm_remove(struct platform_device *pdev)
{
- int i;
- struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
- struct led_pwm_data *leds_data;
+ struct led_pwm *led = platform_get_drvdata(pdev);
+ struct device *d = &pdev->dev;

- leds_data = platform_get_drvdata(pdev);
+ led_classdev_unregister(&led->led);

- for (i = 0; i < pdata->num_leds; i++) {
- led_classdev_unregister(&leds_data[i].cdev);
- pwm_free(leds_data[i].pwm);
+ if (led->pwm) {
+ pwm_stop(led->pwm);
+ pwm_free(led->pwm);
}

- kfree(leds_data);
+ kfree(led);

return 0;
}

static struct platform_driver led_pwm_driver = {
- .probe = led_pwm_probe,
- .remove = __devexit_p(led_pwm_remove),
- .driver = {
- .name = "leds_pwm",
- .owner = THIS_MODULE,
+ .driver = {
+ .name = "leds-pwm",
+ .owner = THIS_MODULE,
},
+ .probe = led_pwm_probe,
+ .remove = led_pwm_remove,
};

-static int __init led_pwm_init(void)
+static int __init led_pwm_modinit(void)
{
return platform_driver_register(&led_pwm_driver);
}
+module_init(led_pwm_modinit);

-static void __exit led_pwm_exit(void)
+static void __exit led_pwm_modexit(void)
{
platform_driver_unregister(&led_pwm_driver);
}
+module_exit(led_pwm_modexit);

-module_init(led_pwm_init);
-module_exit(led_pwm_exit);
-
-MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
-MODULE_DESCRIPTION("PWM LED driver for PXA");
+MODULE_AUTHOR("Bill Gatliff <bgat@billgatliff.com>");
+MODULE_DESCRIPTION("Driver for LEDs with PWM-controlled brightness");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-pwm");
diff --git a/include/linux/pwm/pwm-led.h b/include/linux/pwm/pwm-led.h
new file mode 100644
index 0000000..8ffeecc
--- /dev/null
+++ b/include/linux/pwm/pwm-led.h
@@ -0,0 +1,33 @@
+/*
+ * include/linux/pwm-led.h
+ *
+ * Copyright (C) 2008 Bill Gatliff <bgat@billgatliff.com>
+ *
+ * This program is free software; you may redistribute and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
+ */
+#ifndef __LINUX_PWM_LED_H
+#define __LINUX_PWM_LED_H
+
+struct led_info;
+struct pwm_channel_config;
+
+struct pwm_led_platform_data {
+ const char *bus_id;
+ int chan;
+ struct pwm_channel_config *config;
+ struct led_info *led_info;
+};
+
+#endif /* __LINUX_PWM_LED_H */
--
1.6.5


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