1 files changed, 303 insertions, 0 deletions
diff --git a/arch/arm/plat-pxa/pwm.c b/arch/arm/plat-pxa/pwm.c
new file mode 100644
index 000000000000..a9eabdcfa163
--- /dev/null
+++ b/arch/arm/plat-pxa/pwm.c
@@ -0,0 +1,303 @@
+/*
+ * linux/arch/arm/mach-pxa/pwm.c
+ *
+ * simple driver for PWM (Pulse Width Modulator) controller
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 2008-02-13	initial version
+ * 		eric miao <eric.miao@marvell.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+
+#include <asm/div64.h>
+
+#define HAS_SECONDARY_PWM	0x10
+#define PWM_ID_BASE(d)		((d) & 0xf)
+
+static const struct platform_device_id pwm_id_table[] = {
+	/*   PWM    has_secondary_pwm? */
+	{ "pxa25x-pwm", 0 },
+	{ "pxa27x-pwm", 0 | HAS_SECONDARY_PWM },
+	{ "pxa168-pwm", 1 },
+	{ "pxa910-pwm", 1 },
+	{ },
+};
+MODULE_DEVICE_TABLE(platform, pwm_id_table);
+
+/* PWM registers and bits definitions */
+#define PWMCR		(0x00)
+#define PWMDCR		(0x04)
+#define PWMPCR		(0x08)
+
+#define PWMCR_SD	(1 << 6)
+#define PWMDCR_FD	(1 << 10)
+
+struct pwm_device {
+	struct list_head	node;
+	struct pwm_device	*secondary;
+	struct platform_device	*pdev;
+
+	const char	*label;
+	struct clk	*clk;
+	int		clk_enabled;
+	void __iomem	*mmio_base;
+
+	unsigned int	use_count;
+	unsigned int	pwm_id;
+};
+
+/*
+ * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
+ * duty_ns   = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
+ */
+int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
+{
+	unsigned long long c;
+	unsigned long period_cycles, prescale, pv, dc;
+
+	if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
+		return -EINVAL;
+
+	c = clk_get_rate(pwm->clk);
+	c = c * period_ns;
+	do_div(c, 1000000000);
+	period_cycles = c;
+
+	if (period_cycles < 1)
+		period_cycles = 1;
+	prescale = (period_cycles - 1) / 1024;
+	pv = period_cycles / (prescale + 1) - 1;
+
+	if (prescale > 63)
+		return -EINVAL;
+
+	if (duty_ns == period_ns)
+		dc = PWMDCR_FD;
+	else
+		dc = (pv + 1) * duty_ns / period_ns;
+
+	/* NOTE: the clock to PWM has to be enabled first
+	 * before writing to the registers
+	 */
+	clk_enable(pwm->clk);
+	__raw_writel(prescale, pwm->mmio_base + PWMCR);
+	__raw_writel(dc, pwm->mmio_base + PWMDCR);
+	__raw_writel(pv, pwm->mmio_base + PWMPCR);
+	clk_disable(pwm->clk);
+
+	return 0;
+}
+EXPORT_SYMBOL(pwm_config);
+
+int pwm_enable(struct pwm_device *pwm)
+{
+	int rc = 0;
+
+	if (!pwm->clk_enabled) {
+		rc = clk_enable(pwm->clk);
+		if (!rc)
+			pwm->clk_enabled = 1;
+	}
+	return rc;
+}
+EXPORT_SYMBOL(pwm_enable);
+
+void pwm_disable(struct pwm_device *pwm)
+{
+	if (pwm->clk_enabled) {
+		clk_disable(pwm->clk);
+		pwm->clk_enabled = 0;
+	}
+}
+EXPORT_SYMBOL(pwm_disable);
+
+static DEFINE_MUTEX(pwm_lock);
+static LIST_HEAD(pwm_list);
+
+struct pwm_device *pwm_request(int pwm_id, const char *label)
+{
+	struct pwm_device *pwm;
+	int found = 0;
+
+	mutex_lock(&pwm_lock);
+
+	list_for_each_entry(pwm, &pwm_list, node) {
+		if (pwm->pwm_id == pwm_id) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (found) {
+		if (pwm->use_count == 0) {
+			pwm->use_count++;
+			pwm->label = label;
+		} else
+			pwm = ERR_PTR(-EBUSY);
+	} else
+		pwm = ERR_PTR(-ENOENT);
+
+	mutex_unlock(&pwm_lock);
+	return pwm;
+}
+EXPORT_SYMBOL(pwm_request);
+
+void pwm_free(struct pwm_device *pwm)
+{
+	mutex_lock(&pwm_lock);
+
+	if (pwm->use_count) {
+		pwm->use_count--;
+		pwm->label = NULL;
+	} else
+		pr_warning("PWM device already freed\n");
+
+	mutex_unlock(&pwm_lock);
+}
+EXPORT_SYMBOL(pwm_free);
+
+static inline void __add_pwm(struct pwm_device *pwm)
+{
+	mutex_lock(&pwm_lock);
+	list_add_tail(&pwm->node, &pwm_list);
+	mutex_unlock(&pwm_lock);
+}
+
+static int __devinit pwm_probe(struct platform_device *pdev)
+{
+	struct platform_device_id *id = platform_get_device_id(pdev);
+	struct pwm_device *pwm, *secondary = NULL;
+	struct resource *r;
+	int ret = 0;
+
+	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
+	if (pwm == NULL) {
+		dev_err(&pdev->dev, "failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	pwm->clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(pwm->clk)) {
+		ret = PTR_ERR(pwm->clk);
+		goto err_free;
+	}
+	pwm->clk_enabled = 0;
+
+	pwm->use_count = 0;
+	pwm->pwm_id = PWM_ID_BASE(id->driver_data) + pdev->id;
+	pwm->pdev = pdev;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (r == NULL) {
+		dev_err(&pdev->dev, "no memory resource defined\n");
+		ret = -ENODEV;
+		goto err_free_clk;
+	}
+
+	r = request_mem_region(r->start, r->end - r->start + 1, pdev->name);
+	if (r == NULL) {
+		dev_err(&pdev->dev, "failed to request memory resource\n");
+		ret = -EBUSY;
+		goto err_free_clk;
+	}
+
+	pwm->mmio_base = ioremap(r->start, r->end - r->start + 1);
+	if (pwm->mmio_base == NULL) {
+		dev_err(&pdev->dev, "failed to ioremap() registers\n");
+		ret = -ENODEV;
+		goto err_free_mem;
+	}
+
+	if (id->driver_data & HAS_SECONDARY_PWM) {
+		secondary = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
+		if (secondary == NULL) {
+			ret = -ENOMEM;
+			goto err_free_mem;
+		}
+
+		*secondary = *pwm;
+		pwm->secondary = secondary;
+
+		/* registers for the second PWM has offset of 0x10 */
+		secondary->mmio_base = pwm->mmio_base + 0x10;
+		secondary->pwm_id = pdev->id + 2;
+	}
+
+	__add_pwm(pwm);
+	if (secondary)
+		__add_pwm(secondary);
+
+	platform_set_drvdata(pdev, pwm);
+	return 0;
+
+err_free_mem:
+	release_mem_region(r->start, r->end - r->start + 1);
+err_free_clk:
+	clk_put(pwm->clk);
+err_free:
+	kfree(pwm);
+	return ret;
+}
+
+static int __devexit pwm_remove(struct platform_device *pdev)
+{
+	struct pwm_device *pwm;
+	struct resource *r;
+
+	pwm = platform_get_drvdata(pdev);
+	if (pwm == NULL)
+		return -ENODEV;
+
+	mutex_lock(&pwm_lock);
+
+	if (pwm->secondary) {
+		list_del(&pwm->secondary->node);
+		kfree(pwm->secondary);
+	}
+
+	list_del(&pwm->node);
+	mutex_unlock(&pwm_lock);
+
+	iounmap(pwm->mmio_base);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(r->start, r->end - r->start + 1);
+
+	clk_put(pwm->clk);
+	kfree(pwm);
+	return 0;
+}
+
+static struct platform_driver pwm_driver = {
+	.driver		= {
+		.name	= "pxa25x-pwm",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= pwm_probe,
+	.remove		= __devexit_p(pwm_remove),
+	.id_table	= pwm_id_table,
+};
+
+static int __init pwm_init(void)
+{
+	return platform_driver_register(&pwm_driver);
+}
+arch_initcall(pwm_init);
+
+static void __exit pwm_exit(void)
+{
+	platform_driver_unregister(&pwm_driver);
+}
+module_exit(pwm_exit);
+
+MODULE_LICENSE("GPL v2");