[PWM INTERFACE][drivers/seco/pwm_generic.c] Add driver v1.0 for pwm generic interface

This driver coming from SECO driver library:
    - driver: seco_pwm_generic
    - version: v1.0

    This driver provides a SYSFS interface for a PWM controller.

drivers/seco/Kconfig

@@ -30,4 +30,15 @@ config SECO_PWR_BTN
 
 		if usure, say Y.
 
+
+config SECO_PWM_GEN
+	bool "Generic PWM Support"
+        depends on PWM
+        help
+            This option enables support for a generic PWM. Useful for buzzer since
+            it provides a one shot function with programmable time.
+            You can change pwm parameters through sysfs.
+
+            If unsure, say Y.
+
 endmenu

drivers/seco/Makefile

@@ -7,4 +7,6 @@ obj-$(CONFIG_ECTRL_MSP430)        += ectrl_msp430.o
 obj-$(CONFIG_SECO_CPLD_FW)   += cpld.o cgpio_expander.o lpc_bridge.o sio_w83627.o sio_w83627_gpio.o sio_w83627_serial.o sio_xr28v382.o sio_xr28v382_serial.o pwm_cpld.o
 
 obj-$(CONFIG_SECO_PWR_BTN)   += pwrbutton_management.o
+obj-$(CONFIG_SECO_PWM_GEN)   += pwm_generic.o
+
 

drivers/seco/pwm_generic.c

+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/pwm.h>
+#include <linux/pwm_generic.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+
+#define PWM_NAME_ID   "pwm_generic"
+
+#define PWMG_INFO(fmt, arg...) printk(KERN_INFO "PWM driver: " fmt "\n" , ## arg)
+#define PWMG_ERR(fmt, arg...)  dev_err(&pdev->dev, "%s: " fmt "\n" , __func__ , ## arg)
+#define PWMG_DBG(fmt, arg...)  pr_debug("%s: " fmt "\n" , __func__ , ## arg)
+
+/* One Shot Buzzer Work */
+#define PWMG_WORK_POLLING_JIFFIES	                   msecs_to_jiffies(1)            // 1 milliseconds
+#define DIV_TIME					   1
+
+struct pwmg_data {
+	struct pwm_device	*pwm;
+	struct device		*dev;
+	int			id;
+	unsigned int		period;
+	unsigned int		period_min;
+	unsigned int		period_max;
+	unsigned int		lth_duty;
+	unsigned long		duty;
+	unsigned long		max_duty;
+	int			enable;
+	struct mutex		ops_lock;
+	unsigned long		oneshot;
+	struct delayed_work	pwmg_oneshot_work;
+	struct workqueue_struct *pwmg_workq;
+};
+
+
+static int pwmg_update_status (struct  pwmg_data *pd) {
+
+	int duty = pd->duty;
+	int max = pd->max_duty;
+	
+	if (duty == 0 || pd->enable == 0) {
+		pwm_config (pd->pwm, 0, pd->period);
+		pwm_disable (pd->pwm);
+	} else if (pd->enable == 1) {
+		duty = pd->lth_duty +
+			(duty * (pd->period - pd->lth_duty) / max);
+		pwm_config (pd->pwm, duty, pd->period);
+		pwm_enable (pd->pwm);
+	}
+	return 0;
+}
+
+/*
+ * pwmg_oneshot_work_handler controls wm->oneshot value and it dectivates 
+ * the buzzer when jiffies time becomes less than a given value written through 
+ * sysfs in the parameter oneshot.
+*/
+
+static void pwmg_oneshot_work_handler (struct work_struct *work) {
+
+	struct pwmg_data *wm = container_of(work, struct pwmg_data, pwmg_oneshot_work.work);
+	if(wm->oneshot >= 1) {
+		wm->oneshot = wm->oneshot - 1;
+		queue_delayed_work(wm->pwmg_workq, &wm->pwmg_oneshot_work, PWMG_WORK_POLLING_JIFFIES);
+	}	
+	else {
+		wm->enable = 0;
+		pwmg_update_status(wm);
+	}
+	return;	
+}
+
+static ssize_t pwmg_show_enable (struct device *dev,
+		struct device_attribute *attr, char *buf) {
+	
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+	if (!pd) return 0;
+	return sprintf(buf, "%d\n", pd->enable);
+}
+
+
+static ssize_t pwmg_store_enable (struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count) {
+
+	int rc;
+	unsigned long int  enable;
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+	if (!pd) return 0;
+
+	rc = kstrtoul (buf, 0, &enable);
+	if (rc)
+		return rc;
+
+	rc = -ENXIO;
+
+	mutex_lock (&pd->ops_lock);
+	
+	if (enable == 1 || enable == 0) {
+		pd->enable = enable;
+		pwmg_update_status (pd);
+		rc = count;
+	}
+	
+	mutex_unlock (&pd->ops_lock);
+
+	return rc;
+}
+
+
+static ssize_t pwmg_show_duty (struct device *dev,
+		struct device_attribute *attr, char *buf) {
+	
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+	if (!pd) return 0;
+
+	return sprintf(buf, "%lu\n", pd->duty);
+}
+
+
+static ssize_t pwmg_store_duty (struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count) {
+
+	int rc;
+	unsigned long duty;
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+	if (!pd) return 0;
+
+	rc = kstrtoul (buf, 0, &duty);
+	if (rc)
+		return rc;
+
+	rc = -ENXIO;
+
+	mutex_lock (&pd->ops_lock);
+	if (duty > pd->max_duty)
+			rc = -EINVAL;
+	else {
+		pd->duty = duty;
+		pwmg_update_status (pd);
+		rc = count;
+	}
+	
+	mutex_unlock (&pd->ops_lock);
+
+	return rc;
+}
+
+
+static ssize_t pwmg_show_max_duty (struct device *dev,
+		struct device_attribute *attr, char *buf) {
+
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+	if (!pd) return 0;
+
+	return sprintf(buf, "%lu\n", pd->max_duty);
+}
+
+
+static ssize_t pwmg_show_period (struct device *dev,
+		struct device_attribute *attr, char *buf) {
+
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+	if (!pd) return 0;
+
+	return sprintf(buf, "%d\n", pd->period);
+}
+
+
+static ssize_t pwmg_store_period (struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count) {
+	
+	int rc;
+	unsigned long period;
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+	if (!pd) return 0;
+
+	rc = kstrtoul (buf, 0, &period);
+	if (rc)
+		return rc;
+
+	rc = -ENXIO;
+
+	mutex_lock (&pd->ops_lock);
+	if ((period > pd->period_max) || (period < pd->period_min))
+		rc = -EINVAL;
+	else {
+		pd->lth_duty /= pd->period;
+		pd->period = period;
+		pd->lth_duty = pd->lth_duty * pd->period;
+		pwmg_update_status (pd);
+		rc = count;
+	}
+
+	mutex_unlock (&pd->ops_lock);
+
+	return rc;	
+}
+
+
+static ssize_t pwmg_show_max_period (struct device *dev,
+		struct device_attribute *attr, char *buf) {
+
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+	if (!pd) return 0;
+	return sprintf(buf, "%d\n", pd->period_max);
+}
+
+
+static ssize_t pwmg_show_min_period (struct device *dev,
+		struct device_attribute *attr, char *buf) {
+
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+	if (!pd) return 0;
+
+	return sprintf(buf, "%d\n", pd->period_min);
+}
+
+static ssize_t pwmg_show_oneshot_time (struct device *dev,
+                struct device_attribute *attr, char *buf) {
+
+	struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+        if (!pd) return 0;
+        return sprintf(buf, "%d\n", jiffies_to_msecs(pd->oneshot) / DIV_TIME);
+}
+
+static ssize_t pwmg_store_oneshot_time (struct device *dev,
+                struct device_attribute *attr, const char *buf, size_t count) {
+
+	int rc;
+        unsigned long int  oneshot;
+        struct pwmg_data *pd = (struct pwmg_data *)dev_get_drvdata(dev);
+
+        if (!pd) return 0;
+
+        rc = kstrtoul (buf, 0, &oneshot);
+        if (rc)
+                return rc;
+
+        rc = -ENXIO;
+
+        mutex_lock (&pd->ops_lock);
+
+        if (oneshot >= 0 ) {
+                pd->oneshot =  msecs_to_jiffies(oneshot*DIV_TIME);
+		pd->enable = 1;
+                pwmg_update_status (pd);
+                rc = count;
+		/* launch work */
+                if (pd->pwmg_workq)
+                        queue_delayed_work(pd->pwmg_workq, &pd->pwmg_oneshot_work, PWMG_WORK_POLLING_JIFFIES);
+        }
+	
+        mutex_unlock (&pd->ops_lock);
+
+        return rc;
+
+}
+
+static DEVICE_ATTR (enable, 0644, pwmg_show_enable, pwmg_store_enable);
+static DEVICE_ATTR (duty, 0644, pwmg_show_duty, pwmg_store_duty);
+static DEVICE_ATTR (max_duty, 0444, pwmg_show_max_duty, NULL);
+static DEVICE_ATTR (period_ns, 0644, pwmg_show_period, pwmg_store_period);
+static DEVICE_ATTR (period_ns_max, 0444, pwmg_show_max_period, NULL);
+static DEVICE_ATTR (period_ns_min, 0444, pwmg_show_min_period, NULL);
+static DEVICE_ATTR (oneshot_ms, 0644, pwmg_show_oneshot_time, pwmg_store_oneshot_time);
+
+#ifdef CONFIG_OF
+static int pwmg_generic_parse_dt(struct device *dev,
+                                  struct platform_pwmg_generic_data *data)
+{
+        struct device_node *node = dev->of_node;
+        int ret;
+
+        if (!node)
+                return -ENODEV;
+
+        memset(data, 0, sizeof(*data));
+
+	/* determine the pwm-id */
+
+        ret = of_property_read_u32(node, "pwm-id",
+                                   &(data->pwm_id));
+        if (ret < 0)
+                return ret;
+
+        /* determine the max-duty */
+
+        ret = of_property_read_u32(node, "max-duty",
+                                   &(data->max_duty));
+        if (ret < 0)
+                return ret;
+
+	/* determine the dft-duty */	
+
+	ret = of_property_read_u32(node, "dft-duty",
+                                   &(data->dft_duty));
+        if (ret < 0)
+                return ret;
+
+	/* determine the pwm-period-ns */
+
+        ret = of_property_read_u32(node, "pwm-period-ns",
+                                   &(data->pwm_period_ns));
+        if (ret < 0)
+                return ret;
+
+	 /* determine the period-ns-min */
+
+        ret = of_property_read_u32(node, "period-ns-min",
+                                   &(data->period_ns_min));
+        if (ret < 0)
+                return ret;
+
+	/* determine the period-ns-max */
+
+        ret = of_property_read_u32(node, "period-ns-max",
+                                   &(data->period_ns_max));
+        if (ret < 0)
+                return ret;
+
+	/* determine the enable */
+
+	ret = of_property_read_u32(node, "enable",
+                                   &(data->enable));
+        if (ret < 0)
+                return ret;
+
+        return 0;
+}
+
+static struct of_device_id pwmg_generic_of_match[] = {
+        { .compatible = "pwm-generic" },
+        { }
+};
+
+MODULE_DEVICE_TABLE(of, pwmg_generic_of_match);
+#else
+static int pwmg_generic_parse_dt(struct device *dev,
+                                  struct platform_pwmg_backlight_data *data)
+{
+        return -ENODEV;
+}
+#endif
+
+static int pwmg_generic_probe (struct platform_device *pdev) {
+
+	struct platform_pwmg_generic_data *data = pdev->dev.platform_data;
+	struct platform_pwmg_generic_data defdata;
+	int ret;
+	struct pwmg_data *pd;
+	
+	dev_info(&pdev->dev,"probe...\n");
+
+	if (!data) {
+		ret = pwmg_generic_parse_dt(&pdev->dev, &defdata);
+                if (ret < 0) {
+                        dev_err(&pdev->dev, "failed to find platform data\n");
+                        return ret;
+                }
+
+                data = &defdata;
+	}
+
+	pd = kzalloc (sizeof(*pd), GFP_KERNEL);
+	if (!pd) {
+		PWMG_ERR ("no memory for state");
+		ret = -ENOMEM;
+		goto err_alloc;
+	}
+
+	pd->dev = &pdev->dev;
+	pd->pwm = pwm_get(&pdev->dev, NULL);
+        if (IS_ERR(pd->pwm)) {
+                dev_info(&pdev->dev, "unable to request PWM, trying legacy API\n");
+                pd->pwm = pwm_request(data->pwm_id, PWM_NAME_ID);
+        }
+	if (IS_ERR(pd->pwm)) {
+		PWMG_ERR ("unable to request PWM");
+		ret = PTR_ERR(pd->pwm);
+		goto err_pwm;
+	} else
+		PWMG_DBG ("got pwm for backlight\n");
+
+	data->reserved = pd;
+
+	pd->duty = data->dft_duty;
+	pd->max_duty = data->max_duty;
+	
+	pd->period = data->pwm_period_ns;
+	pd->period_max = data->period_ns_max;
+	pd->period_min = data->period_ns_min;
+
+	pd->lth_duty = data->lth_duty *
+		(data->pwm_period_ns / data->max_duty);
+
+	pd->enable = data->enable;
+
+	mutex_init(&pd->ops_lock);
+
+	ret = device_create_file (pd->dev, &dev_attr_enable);
+	if (ret < 0)
+		goto err_fs;
+	ret = device_create_file (pd->dev, &dev_attr_duty);
+	if (ret < 0)
+		goto err_fs;
+	ret = device_create_file (pd->dev, &dev_attr_max_duty);
+	if (ret < 0)
+		goto err_fs;
+	ret = device_create_file (pd->dev, &dev_attr_period_ns);
+	if (ret < 0)
+		goto err_fs;
+	ret = device_create_file (pd->dev, &dev_attr_period_ns_max);
+	if (ret < 0)
+		goto err_fs;
+	ret = device_create_file (pd->dev, &dev_attr_period_ns_min);
+	if (ret < 0)
+		goto err_fs;
+	ret = device_create_file (pd->dev, &dev_attr_oneshot_ms);
+	if (ret < 0)
+		goto err_fs;
+	pwmg_update_status (pd);
+
+	/* Create workqueue */
+	pd->pwmg_workq = create_singlethread_workqueue("pwmg_oneshot");
+        if (pd->pwmg_workq == NULL) {
+                return -EINVAL;
+        }
+	INIT_DELAYED_WORK(&pd->pwmg_oneshot_work, pwmg_oneshot_work_handler );
+	
+	platform_set_drvdata(pdev, pd);
+	
+	return 0;
+
+err_fs:
+	pwm_free(pd->pwm);
+err_pwm:
+	kfree(pd);
+err_alloc:
+	return ret;
+}
+
+
+static int pwmg_generic_remove(struct platform_device *pdev) {
+
+	struct platform_pwmg_generic_data *data = pdev->dev.platform_data;
+	struct pwmg_data *pd = (struct pwmg_data *)data->reserved;
+
+	pwm_config (pd->pwm, 0, pd->period);
+        pwm_disable (pd->pwm);
+        pwm_free (pd->pwm);
+        kfree (pd);
+	return 0;
+}
+
+
+static int pwmg_generic_suspend(struct device *pdev) {
+	return 0;
+}
+
+
+static int pwmg_generic_resume (struct device *pdev) {
+	return 0;
+}
+
+static const struct dev_pm_ops pwmg_generic_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
+	.suspend        = pwmg_generic_suspend,
+        .resume         = pwmg_generic_resume,
+#endif
+};
+
+static struct platform_driver pwmg_generic_driver = {
+	.driver		= {
+		.name	= "pwm-generic",
+		.of_match_table = of_match_ptr(pwmg_generic_of_match),
+	},
+	.probe		= pwmg_generic_probe,
+	.remove		= pwmg_generic_remove,
+};
+
+module_platform_driver(pwmg_generic_driver);
+
+MODULE_AUTHOR("DC MS SECO");
+MODULE_DESCRIPTION("SECO generic PWM Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pwm-generic");

include/linux/pwm_generic.h

+/*
+ * Generic PWM data - see drivers/seco/pwm_generic.h
+ */
+#ifndef __LINUX_PWM_GENERIC_H
+#define __LINUX_PWM_GENERIC_H
+
+
+#define MAX_PERIOD_NS 50000000    // 50 ms
+#define MIN_PERIOD_NS 150	  // 150 ns
+
+struct platform_pwmg_generic_data {
+	int            pwm_id;
+	unsigned int   max_duty;
+	unsigned int   dft_duty;
+	unsigned int   lth_duty;
+	unsigned int   pwm_period_ns;
+	unsigned int   period_ns_max;
+	unsigned int   period_ns_min;
+	void           *reserved;
+	unsigned int   enable;
+};
+
+#endif