diff options
Diffstat (limited to 'drivers/leds/leds-stmp378x-pwm.c')
| -rw-r--r-- | drivers/leds/leds-stmp378x-pwm.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/leds/leds-stmp378x-pwm.c b/drivers/leds/leds-stmp378x-pwm.c new file mode 100644 index 000000000000..f0865db4eb90 --- /dev/null +++ b/drivers/leds/leds-stmp378x-pwm.c @@ -0,0 +1,190 @@ +/* + * Freescale STMP378X PWM LED driver + * + * Author: Drew Benedetti <drewb@embeddedalley.com> + * + * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved. + * 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/clk.h> +#include <mach/hardware.h> +#include <mach/regs-pwm.h> +#include <mach/regs-clkctrl.h> +#include <mach/pwm-led.h> +#include <mach/stmp3xxx.h> + +/* Up to 5 PWM lines are available. */ +#define PWM_MAX 5 + +/* PWM enables are the lowest PWM_MAX bits of HW_PWM_CTRL register */ +#define BM_PWM_CTRL_PWM_ENABLE(n) ((1<<(n)) & ((1<<(PWM_MAX))-1)) +#define BF_PWM_PERIODn_SETTINGS \ + (BF_PWM_PERIODn_CDIV(5) | /* divide by 64 */ \ + BF_PWM_PERIODn_INACTIVE_STATE(2) | /* low */ \ + BF_PWM_PERIODn_ACTIVE_STATE(3) | /* high */ \ + BF_PWM_PERIODn_PERIOD(LED_FULL)) /* 255 cycles */ + +struct stmp378x_led { + struct led_classdev led_dev; + int in_use; +}; + +static struct stmp378x_led leds[PWM_MAX]; + +static struct clk *pwm_clk; + +static void stmp378x_pwm_led_brightness_set(struct led_classdev *pled, + enum led_brightness value) +{ + unsigned int pwmn; + + pwmn = container_of(pled, struct stmp378x_led, led_dev) - leds; + + if (pwmn < PWM_MAX && leds[pwmn].in_use) { + HW_PWM_CTRL_CLR(BM_PWM_CTRL_PWM_ENABLE(pwmn)); + HW_PWM_ACTIVEn_WR(pwmn, BF_PWM_ACTIVEn_INACTIVE(value) | + BF_PWM_ACTIVEn_ACTIVE(0)); + HW_PWM_PERIODn_WR(pwmn, BF_PWM_PERIODn_SETTINGS); + HW_PWM_CTRL_SET(BM_PWM_CTRL_PWM_ENABLE(pwmn)); + } +} + +static int stmp378x_pwm_led_probe(struct platform_device *pdev) +{ + struct led_classdev *led; + unsigned int pwmn; + int leds_in_use = 0, rc = 0; + int i; + + stmp3xxx_reset_block(REGS_PWM_BASE, 1); + + pwm_clk = clk_get(&pdev->dev, "pwm"); + if (IS_ERR(pwm_clk)) { + rc = PTR_ERR(pwm_clk); + return rc; + } + + clk_enable(pwm_clk); + + for (i = 0; i < pdev->num_resources; i++) { + + if (pdev->resource[i].flags & IORESOURCE_DISABLED) + continue; + + pwmn = pdev->resource[i].start; + if (pwmn >= PWM_MAX) { + dev_err(&pdev->dev, "PWM %d doesn't exist\n", pwmn); + continue; + } + + rc = pwm_led_pinmux_request(pwmn, "stmp378x_pwm_led"); + if (rc) { + dev_err(&pdev->dev, + "PWM %d is not available (err=%d)\n", + pwmn, rc); + continue; + } + + led = &leds[pwmn].led_dev; + + led->flags = pdev->resource[i].flags; + led->name = pdev->resource[i].name; + led->brightness = LED_HALF; + led->flags = 0; + led->brightness_set = stmp378x_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", + pwmn, rc); + pwm_led_pinmux_free(pwmn, "stmp378x_pwm_led"); + continue; + } + + /* PWM LED is available now */ + leds[pwmn].in_use = !0; + leds_in_use++; + + /* Set default brightness */ + stmp378x_pwm_led_brightness_set(led, LED_HALF); + } + + if (leds_in_use == 0) { + dev_info(&pdev->dev, "No PWM LEDs available\n"); + clk_disable(pwm_clk); + clk_put(pwm_clk); + return -ENODEV; + } + + return 0; +} + +static int stmp378x_pwm_led_remove(struct platform_device *pdev) +{ + unsigned int pwmn; + + for (pwmn = 0; pwmn < PWM_MAX; pwmn++) { + + if (!leds[pwmn].in_use) + continue; + + /* Disable LED */ + HW_PWM_CTRL_CLR(BM_PWM_CTRL_PWM_ENABLE(pwmn)); + HW_PWM_ACTIVEn_WR(pwmn, BF_PWM_ACTIVEn_INACTIVE(0) | + BF_PWM_ACTIVEn_ACTIVE(0)); + HW_PWM_PERIODn_WR(pwmn, BF_PWM_PERIODn_SETTINGS); + + led_classdev_unregister(&leds[pwmn].led_dev); + pwm_led_pinmux_free(pwmn, "stmp378x_pwm_led"); + + leds[pwmn].led_dev.name = 0; + leds[pwmn].in_use = 0; + } + + clk_disable(pwm_clk); + clk_put(pwm_clk); + + return 0; +} + + +static struct platform_driver stmp378x_pwm_led_driver = { + .probe = stmp378x_pwm_led_probe, + .remove = stmp378x_pwm_led_remove, + .driver = { + .name = "stmp378x-pwm-led", + }, +}; + +static int __init stmp378x_pwm_led_init(void) +{ + return platform_driver_register(&stmp378x_pwm_led_driver); +} + +static void __exit stmp378x_pwm_led_exit(void) +{ + platform_driver_unregister(&stmp378x_pwm_led_driver); +} + +module_init(stmp378x_pwm_led_init); +module_exit(stmp378x_pwm_led_exit); + +MODULE_AUTHOR("Drew Benedetti <drewb@embeddedalley.com>"); +MODULE_DESCRIPTION("STMP378X PWM LED driver"); +MODULE_LICENSE("GPL"); |