diff options
Diffstat (limited to 'drivers/leds/leds-mxs-pwm.c')
| -rw-r--r-- | drivers/leds/leds-mxs-pwm.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/drivers/leds/leds-mxs-pwm.c b/drivers/leds/leds-mxs-pwm.c new file mode 100644 index 000000000000..a546900a44d0 --- /dev/null +++ b/drivers/leds/leds-mxs-pwm.c @@ -0,0 +1,217 @@ +/* + * Freescale MXS PWM LED driver + * + * Author: Drew Benedetti <drewb@embeddedalley.com> + * + * Copyright 2008-2010 Freescale Semiconductor, Inc. + * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. + */ + +/* + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/leds.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/clk.h> + +#include <mach/hardware.h> +#include <mach/system.h> +#include <mach/device.h> +#include <mach/regs-pwm.h> + + +/* + * PWM enables are the lowest bits of HW_PWM_CTRL register + */ +#define BM_PWM_CTRL_PWM_ENABLE ((1<<(CONFIG_MXS_PWM_CHANNELS)) - 1) +#define BF_PWM_CTRL_PWM_ENABLE(n) ((1<<(n)) & BM_PWM_CTRL_PWM_ENABLE) + +#define BF_PWM_PERIODn_SETTINGS \ + (BF_PWM_PERIODn_CDIV(5) | /* divide by 64 */ \ + BF_PWM_PERIODn_INACTIVE_STATE(3) | /* low */ \ + BF_PWM_PERIODn_ACTIVE_STATE(2) | /* high */ \ + BF_PWM_PERIODn_PERIOD(LED_FULL)) /* 255 cycles */ + +struct mxs_pwm_leds { + struct clk *pwm_clk; + unsigned int base; + unsigned int led_num; + struct mxs_pwm_led *leds; +}; + +static struct mxs_pwm_leds leds; + +static void mxs_pwm_led_brightness_set(struct led_classdev *pled, + enum led_brightness value) +{ + struct mxs_pwm_led *pwm_led; + + pwm_led = container_of(pled, struct mxs_pwm_led, dev); + + if (pwm_led->pwm < CONFIG_MXS_PWM_CHANNELS) { + __raw_writel(BF_PWM_CTRL_PWM_ENABLE(pwm_led->pwm), + leds.base + HW_PWM_CTRL_CLR); + __raw_writel(BF_PWM_ACTIVEn_INACTIVE(LED_FULL) | + BF_PWM_ACTIVEn_ACTIVE(value), + leds.base + HW_PWM_ACTIVEn(pwm_led->pwm)); + __raw_writel(BF_PWM_PERIODn_SETTINGS, + leds.base + HW_PWM_PERIODn(pwm_led->pwm)); + __raw_writel(BF_PWM_CTRL_PWM_ENABLE(pwm_led->pwm), + leds.base + HW_PWM_CTRL_SET); + } +} + +static int __devinit mxs_pwm_led_probe(struct platform_device *pdev) +{ + struct mxs_pwm_leds_plat_data *plat_data; + struct resource *res; + struct led_classdev *led; + unsigned int pwmn; + int leds_in_use = 0, rc = 0; + int i; + + plat_data = (struct mxs_pwm_leds_plat_data *)pdev->dev.platform_data; + if (plat_data == NULL) + return -ENODEV; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (res == NULL) + return -ENODEV; + leds.base = (unsigned int)IO_ADDRESS(res->start); + + mxs_reset_block((void __iomem *)leds.base, 1); + + leds.led_num = plat_data->num; + if (leds.led_num <= 0 || leds.led_num > CONFIG_MXS_PWM_CHANNELS) + return -EFAULT; + leds.leds = plat_data->leds; + if (leds.leds == NULL) + return -EFAULT; + + leds.pwm_clk = clk_get(&pdev->dev, "pwm"); + if (IS_ERR(leds.pwm_clk)) { + rc = PTR_ERR(leds.pwm_clk); + return rc; + } + + clk_enable(leds.pwm_clk); + + for (i = 0; i < leds.led_num; i++) { + pwmn = leds.leds[i].pwm; + if (pwmn >= CONFIG_MXS_PWM_CHANNELS) { + dev_err(&pdev->dev, + "[led-pwm%d]:PWM %d doesn't exist\n", + i, pwmn); + continue; + } + led = &(leds.leds[i].dev); + led->name = leds.leds[i].name; + led->brightness = LED_HALF; + led->flags = 0; + led->brightness_set = mxs_pwm_led_brightness_set; + led->default_trigger = 0; + + rc = led_classdev_register(&pdev->dev, led); + if (rc < 0) { + dev_err(&pdev->dev, + "Unable to register LED device %d (err=%d)\n", + i, rc); + continue; + } + + leds_in_use++; + + /* Set default brightness */ + mxs_pwm_led_brightness_set(led, LED_HALF); + } + + if (leds_in_use == 0) { + dev_info(&pdev->dev, "No PWM LEDs available\n"); + clk_disable(leds.pwm_clk); + clk_put(leds.pwm_clk); + return -ENODEV; + } + return 0; +} + +static int __devexit mxs_pwm_led_remove(struct platform_device *pdev) +{ + int i; + unsigned int pwm; + for (i = 0; i < leds.led_num; i++) { + pwm = leds.leds[i].pwm; + __raw_writel(BF_PWM_CTRL_PWM_ENABLE(pwm), + leds.base + HW_PWM_CTRL_CLR); + __raw_writel(BF_PWM_ACTIVEn_INACTIVE(0) | + BF_PWM_ACTIVEn_ACTIVE(0), + leds.base + HW_PWM_ACTIVEn(pwm)); + __raw_writel(BF_PWM_PERIODn_SETTINGS, + leds.base + HW_PWM_PERIODn(pwm)); + led_classdev_unregister(&leds.leds[i].dev); + } + + clk_disable(leds.pwm_clk); + clk_put(leds.pwm_clk); + + return 0; +} + +#ifdef CONFIG_PM +static int mxs_led_suspend(struct platform_device *dev, pm_message_t state) +{ + int i; + + for (i = 0; i < leds.led_num; i++) + led_classdev_suspend(&leds.leds[i].dev); + return 0; +} + +static int mxs_led_resume(struct platform_device *dev) +{ + int i; + + for (i = 0; i < leds.led_num; i++) + led_classdev_resume(&leds.leds[i].dev); + return 0; +} +#else +#define mxs_led_suspend NULL +#define mxs_led_resume NULL +#endif + + +static struct platform_driver mxs_pwm_led_driver = { + .probe = mxs_pwm_led_probe, + .remove = __devexit_p(mxs_pwm_led_remove), + .suspend = mxs_led_suspend, + .resume = mxs_led_resume, + .driver = { + .name = "mxs-leds", + }, +}; + +static int __init mxs_pwm_led_init(void) +{ + return platform_driver_register(&mxs_pwm_led_driver); +} + +static void __exit mxs_pwm_led_exit(void) +{ + platform_driver_unregister(&mxs_pwm_led_driver); +} + +module_init(mxs_pwm_led_init); +module_exit(mxs_pwm_led_exit); + +MODULE_AUTHOR("Drew Benedetti <drewb@embeddedalley.com>"); +MODULE_DESCRIPTION("mxs PWM LED driver"); +MODULE_LICENSE("GPL"); |