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path: root/drivers/misc/ep93xx_pwm.c
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Diffstat (limited to 'drivers/misc/ep93xx_pwm.c')
-rw-r--r--drivers/misc/ep93xx_pwm.c286
1 files changed, 286 insertions, 0 deletions
diff --git a/drivers/misc/ep93xx_pwm.c b/drivers/misc/ep93xx_pwm.c
new file mode 100644
index 0000000..cdb67a9
--- /dev/null
+++ b/drivers/misc/ep93xx_pwm.c
@@ -0,0 +1,286 @@
+/*
+ * Simple PWM driver for EP93XX
+ *
+ * (c) Copyright 2009 Matthieu Crapet <mcrapet@gmail.com>
+ * (c) Copyright 2009 H Hartley Sweeten <hsweeten@visionengravers.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * EP9307 has only one channel:
+ * - PWMOUT
+ *
+ * EP9301/02/12/15 have two channels:
+ * - PWMOUT
+ * - PWMOUT1 (alternate function for EGPIO14)
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+
+#include <mach/platform.h>
+
+#define EP93XX_PWMx_TERM_COUNT 0x00
+#define EP93XX_PWMx_DUTY_CYCLE 0x04
+#define EP93XX_PWMx_ENABLE 0x08
+#define EP93XX_PWMx_INVERT 0x0C
+
+#define EP93XX_PWM_MAX_COUNT 0xFFFF
+
+struct ep93xx_pwm {
+ void __iomem *mmio_base;
+ struct clk *clk;
+ u32 duty_percent;
+};
+
+/*
+ * /sys/devices/platform/ep93xx-pwm.N
+ * /min_freq read-only minimum pwm output frequency
+ * /max_req read-only maximum pwm output frequency
+ * /freq read-write pwm output frequency (0 = disable output)
+ * /duty_percent read-write pwm duty cycle percent (1..99)
+ * /invert read-write invert pwm output
+ */
+
+static ssize_t ep93xx_pwm_get_min_freq(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
+ unsigned long rate = clk_get_rate(pwm->clk);
+
+ return sprintf(buf, "%ld\n", rate / (EP93XX_PWM_MAX_COUNT + 1));
+}
+
+static ssize_t ep93xx_pwm_get_max_freq(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
+ unsigned long rate = clk_get_rate(pwm->clk);
+
+ return sprintf(buf, "%ld\n", rate / 2);
+}
+
+static ssize_t ep93xx_pwm_get_freq(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
+
+ if (readl(pwm->mmio_base + EP93XX_PWMx_ENABLE) & 0x1) {
+ unsigned long rate = clk_get_rate(pwm->clk);
+ u16 term = readl(pwm->mmio_base + EP93XX_PWMx_TERM_COUNT);
+
+ return sprintf(buf, "%ld\n", rate / (term + 1));
+ } else {
+ return sprintf(buf, "disabled\n");
+ }
+}
+
+static ssize_t ep93xx_pwm_set_freq(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
+ long val;
+ int err;
+
+ err = kstrtol(buf, 10, &val);
+ if (err)
+ return -EINVAL;
+
+ if (val == 0) {
+ writel(0x0, pwm->mmio_base + EP93XX_PWMx_ENABLE);
+ } else if (val <= (clk_get_rate(pwm->clk) / 2)) {
+ u32 term, duty;
+
+ val = (clk_get_rate(pwm->clk) / val) - 1;
+ if (val > EP93XX_PWM_MAX_COUNT)
+ val = EP93XX_PWM_MAX_COUNT;
+ if (val < 1)
+ val = 1;
+
+ term = readl(pwm->mmio_base + EP93XX_PWMx_TERM_COUNT);
+ duty = ((val + 1) * pwm->duty_percent / 100) - 1;
+
+ /* If pwm is running, order is important */
+ if (val > term) {
+ writel(val, pwm->mmio_base + EP93XX_PWMx_TERM_COUNT);
+ writel(duty, pwm->mmio_base + EP93XX_PWMx_DUTY_CYCLE);
+ } else {
+ writel(duty, pwm->mmio_base + EP93XX_PWMx_DUTY_CYCLE);
+ writel(val, pwm->mmio_base + EP93XX_PWMx_TERM_COUNT);
+ }
+
+ if (!readl(pwm->mmio_base + EP93XX_PWMx_ENABLE) & 0x1)
+ writel(0x1, pwm->mmio_base + EP93XX_PWMx_ENABLE);
+ } else {
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+static ssize_t ep93xx_pwm_get_duty_percent(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
+
+ return sprintf(buf, "%d\n", pwm->duty_percent);
+}
+
+static ssize_t ep93xx_pwm_set_duty_percent(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
+ long val;
+ int err;
+
+ err = kstrtol(buf, 10, &val);
+ if (err)
+ return -EINVAL;
+
+ if (val > 0 && val < 100) {
+ u32 term = readl(pwm->mmio_base + EP93XX_PWMx_TERM_COUNT);
+ u32 duty = ((term + 1) * val / 100) - 1;
+
+ writel(duty, pwm->mmio_base + EP93XX_PWMx_DUTY_CYCLE);
+ pwm->duty_percent = val;
+ return count;
+ }
+
+ return -EINVAL;
+}
+
+static ssize_t ep93xx_pwm_get_invert(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
+ int inverted = readl(pwm->mmio_base + EP93XX_PWMx_INVERT) & 0x1;
+
+ return sprintf(buf, "%d\n", inverted);
+}
+
+static ssize_t ep93xx_pwm_set_invert(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
+ long val;
+ int err;
+
+ err = kstrtol(buf, 10, &val);
+ if (err)
+ return -EINVAL;
+
+ if (val == 0)
+ writel(0x0, pwm->mmio_base + EP93XX_PWMx_INVERT);
+ else if (val == 1)
+ writel(0x1, pwm->mmio_base + EP93XX_PWMx_INVERT);
+ else
+ return -EINVAL;
+
+ return count;
+}
+
+static DEVICE_ATTR(min_freq, S_IRUGO, ep93xx_pwm_get_min_freq, NULL);
+static DEVICE_ATTR(max_freq, S_IRUGO, ep93xx_pwm_get_max_freq, NULL);
+static DEVICE_ATTR(freq, S_IWUSR | S_IRUGO,
+ ep93xx_pwm_get_freq, ep93xx_pwm_set_freq);
+static DEVICE_ATTR(duty_percent, S_IWUSR | S_IRUGO,
+ ep93xx_pwm_get_duty_percent, ep93xx_pwm_set_duty_percent);
+static DEVICE_ATTR(invert, S_IWUSR | S_IRUGO,
+ ep93xx_pwm_get_invert, ep93xx_pwm_set_invert);
+
+static struct attribute *ep93xx_pwm_attrs[] = {
+ &dev_attr_min_freq.attr,
+ &dev_attr_max_freq.attr,
+ &dev_attr_freq.attr,
+ &dev_attr_duty_percent.attr,
+ &dev_attr_invert.attr,
+ NULL
+};
+
+static const struct attribute_group ep93xx_pwm_sysfs_files = {
+ .attrs = ep93xx_pwm_attrs,
+};
+
+static int ep93xx_pwm_probe(struct platform_device *pdev)
+{
+ struct ep93xx_pwm *pwm;
+ struct resource *res;
+ int ret;
+
+ pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+ if (!pwm)
+ return -ENOMEM;
+
+ pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk");
+ if (IS_ERR(pwm->clk))
+ return PTR_ERR(pwm->clk);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ pwm->mmio_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(pwm->mmio_base))
+ return PTR_ERR(pwm->mmio_base);
+
+ ret = ep93xx_pwm_acquire_gpio(pdev);
+ if (ret)
+ return ret;
+
+ ret = sysfs_create_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
+ if (ret) {
+ ep93xx_pwm_release_gpio(pdev);
+ return ret;
+ }
+
+ pwm->duty_percent = 50;
+
+ /* disable pwm at startup. Avoids zero value. */
+ writel(0x0, pwm->mmio_base + EP93XX_PWMx_ENABLE);
+ writel(EP93XX_PWM_MAX_COUNT, pwm->mmio_base + EP93XX_PWMx_TERM_COUNT);
+ writel(EP93XX_PWM_MAX_COUNT/2, pwm->mmio_base + EP93XX_PWMx_DUTY_CYCLE);
+
+ clk_enable(pwm->clk);
+
+ platform_set_drvdata(pdev, pwm);
+ return 0;
+}
+
+static int ep93xx_pwm_remove(struct platform_device *pdev)
+{
+ struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
+
+ writel(0x0, pwm->mmio_base + EP93XX_PWMx_ENABLE);
+ clk_disable(pwm->clk);
+ sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
+ ep93xx_pwm_release_gpio(pdev);
+
+ return 0;
+}
+
+static struct platform_driver ep93xx_pwm_driver = {
+ .driver = {
+ .name = "ep93xx-pwm",
+ .owner = THIS_MODULE,
+ },
+ .probe = ep93xx_pwm_probe,
+ .remove = ep93xx_pwm_remove,
+};
+module_platform_driver(ep93xx_pwm_driver);
+
+MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>, "
+ "H Hartley Sweeten <hsweeten@visionengravers.com>");
+MODULE_DESCRIPTION("EP93xx PWM driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ep93xx-pwm");
generated by cgit v0.10.2 at 2024-06-26 10:50:41 (GMT)