diff options
Diffstat (limited to 'drivers/misc/ab8500-pwm.c')
| -rw-r--r-- | drivers/misc/ab8500-pwm.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/drivers/misc/ab8500-pwm.c b/drivers/misc/ab8500-pwm.c new file mode 100644 index 00000000..d7a9aa14 --- /dev/null +++ b/drivers/misc/ab8500-pwm.c @@ -0,0 +1,169 @@ +/* + * Copyright (C) ST-Ericsson SA 2010 + * + * Author: Arun R Murthy <arun.murthy@stericsson.com> + * License terms: GNU General Public License (GPL) version 2 + */ +#include <linux/err.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/pwm.h> +#include <linux/mfd/abx500.h> +#include <linux/mfd/abx500/ab8500.h> +#include <linux/module.h> + +/* + * PWM Out generators + * Bank: 0x10 + */ +#define AB8500_PWM_OUT_CTRL1_REG 0x60 +#define AB8500_PWM_OUT_CTRL2_REG 0x61 +#define AB8500_PWM_OUT_CTRL7_REG 0x66 + +/* backlight driver constants */ +#define ENABLE_PWM 1 +#define DISABLE_PWM 0 + +struct pwm_device { + struct device *dev; + struct list_head node; + const char *label; + unsigned int pwm_id; +}; + +static LIST_HEAD(pwm_list); + +int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) +{ + int ret = 0; + unsigned int higher_val, lower_val; + u8 reg; + + /* + * get the first 8 bits that are be written to + * AB8500_PWM_OUT_CTRL1_REG[0:7] + */ + lower_val = duty_ns & 0x00FF; + /* + * get bits [9:10] that are to be written to + * AB8500_PWM_OUT_CTRL2_REG[0:1] + */ + higher_val = ((duty_ns & 0x0300) >> 8); + + reg = AB8500_PWM_OUT_CTRL1_REG + ((pwm->pwm_id - 1) * 2); + + ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC, + reg, (u8)lower_val); + if (ret < 0) + return ret; + ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC, + (reg + 1), (u8)higher_val); + + return ret; +} +EXPORT_SYMBOL(pwm_config); + +int pwm_enable(struct pwm_device *pwm) +{ + int ret; + + ret = abx500_mask_and_set_register_interruptible(pwm->dev, + AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG, + 1 << (pwm->pwm_id-1), ENABLE_PWM); + if (ret < 0) + dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n", + pwm->label, ret); + return ret; +} +EXPORT_SYMBOL(pwm_enable); + +void pwm_disable(struct pwm_device *pwm) +{ + int ret; + + ret = abx500_mask_and_set_register_interruptible(pwm->dev, + AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG, + 1 << (pwm->pwm_id-1), DISABLE_PWM); + if (ret < 0) + dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n", + pwm->label, ret); + return; +} +EXPORT_SYMBOL(pwm_disable); + +struct pwm_device *pwm_request(int pwm_id, const char *label) +{ + struct pwm_device *pwm; + + list_for_each_entry(pwm, &pwm_list, node) { + if (pwm->pwm_id == pwm_id) { + pwm->label = label; + pwm->pwm_id = pwm_id; + return pwm; + } + } + + return ERR_PTR(-ENOENT); +} +EXPORT_SYMBOL(pwm_request); + +void pwm_free(struct pwm_device *pwm) +{ + pwm_disable(pwm); +} +EXPORT_SYMBOL(pwm_free); + +static int __devinit ab8500_pwm_probe(struct platform_device *pdev) +{ + struct pwm_device *pwm; + /* + * Nothing to be done in probe, this is required to get the + * device which is required for ab8500 read and write + */ + pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); + if (pwm == NULL) { + dev_err(&pdev->dev, "failed to allocate memory\n"); + return -ENOMEM; + } + pwm->dev = &pdev->dev; + pwm->pwm_id = pdev->id; + list_add_tail(&pwm->node, &pwm_list); + platform_set_drvdata(pdev, pwm); + dev_dbg(pwm->dev, "pwm probe successful\n"); + return 0; +} + +static int __devexit ab8500_pwm_remove(struct platform_device *pdev) +{ + struct pwm_device *pwm = platform_get_drvdata(pdev); + list_del(&pwm->node); + dev_dbg(&pdev->dev, "pwm driver removed\n"); + kfree(pwm); + return 0; +} + +static struct platform_driver ab8500_pwm_driver = { + .driver = { + .name = "ab8500-pwm", + .owner = THIS_MODULE, + }, + .probe = ab8500_pwm_probe, + .remove = __devexit_p(ab8500_pwm_remove), +}; + +static int __init ab8500_pwm_init(void) +{ + return platform_driver_register(&ab8500_pwm_driver); +} + +static void __exit ab8500_pwm_exit(void) +{ + platform_driver_unregister(&ab8500_pwm_driver); +} + +subsys_initcall(ab8500_pwm_init); +module_exit(ab8500_pwm_exit); +MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>"); +MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver"); +MODULE_ALIAS("platform:ab8500-pwm"); +MODULE_LICENSE("GPL v2"); |