ARM vt8500: Move vt8500 pwm driver to pwm framework

Move the driver to drivers/pwm/ and convert it to use the framework.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Alexey Charkov <alchark@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

1 files changed, 208 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c
new file mode 100644
index 00000000000..3db0746f720
--- /dev/null
+++ b/drivers/pwm/pwm-vt8500.c
@@ -0,0 +1,208 @@
+/*
+ * arch/arm/mach-vt8500/pwm.c
+ *
+ *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+#include <linux/delay.h>
+
+#include <asm/div64.h>
+
+#define VT8500_NR_PWMS 4
+
+struct vt8500_chip {
+	struct pwm_chip chip;
+	void __iomem *base;
+};
+
+#define to_vt8500_chip(chip)	container_of(chip, struct vt8500_chip, chip)
+
+#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
+static inline void pwm_busy_wait(void __iomem *reg, u8 bitmask)
+{
+	int loops = msecs_to_loops(10);
+	while ((readb(reg) & bitmask) && --loops)
+		cpu_relax();
+
+	if (unlikely(!loops))
+		pr_warning("Waiting for status bits 0x%x to clear timed out\n",
+			   bitmask);
+}
+
+static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+		int duty_ns, int period_ns)
+{
+	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
+	unsigned long long c;
+	unsigned long period_cycles, prescale, pv, dc;
+
+	c = 25000000/2; /* wild guess --- need to implement clocks */
+	c = c * period_ns;
+	do_div(c, 1000000000);
+	period_cycles = c;
+
+	if (period_cycles < 1)
+		period_cycles = 1;
+	prescale = (period_cycles - 1) / 4096;
+	pv = period_cycles / (prescale + 1) - 1;
+	if (pv > 4095)
+		pv = 4095;
+
+	if (prescale > 1023)
+		return -EINVAL;
+
+	c = (unsigned long long)pv * duty_ns;
+	do_div(c, period_ns);
+	dc = c;
+
+	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 1));
+	writel(prescale, vt8500->base + 0x4 + (pwm->hwpwm << 4));
+
+	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 2));
+	writel(pv, vt8500->base + 0x8 + (pwm->hwpwm << 4));
+
+	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 3));
+	writel(dc, vt8500->base + 0xc + (pwm->hwpwm << 4));
+
+	return 0;
+}
+
+static int vt8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
+
+	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0));
+	writel(5, vt8500->base + (pwm->hwpwm << 4));
+	return 0;
+}
+
+static void vt8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
+
+	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0));
+	writel(0, vt8500->base + (pwm->hwpwm << 4));
+}
+
+static struct pwm_ops vt8500_pwm_ops = {
+	.enable = vt8500_pwm_enable,
+	.disable = vt8500_pwm_disable,
+	.config = vt8500_pwm_config,
+	.owner = THIS_MODULE,
+};
+
+static int __devinit pwm_probe(struct platform_device *pdev)
+{
+	struct vt8500_chip *chip;
+	struct resource *r;
+	int ret;
+
+	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+	if (chip == NULL) {
+		dev_err(&pdev->dev, "failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	chip->chip.dev = &pdev->dev;
+	chip->chip.ops = &vt8500_pwm_ops;
+	chip->chip.base = -1;
+	chip->chip.npwm = VT8500_NR_PWMS;
+
+	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;
+	}
+
+	r = request_mem_region(r->start, resource_size(r), pdev->name);
+	if (r == NULL) {
+		dev_err(&pdev->dev, "failed to request memory resource\n");
+		ret = -EBUSY;
+		goto err_free;
+	}
+
+	chip->base = ioremap(r->start, resource_size(r));
+	if (chip->base == NULL) {
+		dev_err(&pdev->dev, "failed to ioremap() registers\n");
+		ret = -ENODEV;
+		goto err_free_mem;
+	}
+
+	ret = pwmchip_add(&chip->chip);
+	if (ret < 0)
+		goto err_unmap;
+
+	platform_set_drvdata(pdev, chip);
+	return ret;
+
+err_unmap:
+	iounmap(chip->base);
+err_free_mem:
+	release_mem_region(r->start, resource_size(r));
+err_free:
+	kfree(chip);
+	return ret;
+}
+
+static int __devexit pwm_remove(struct platform_device *pdev)
+{
+	struct vt8500_chip *chip;
+	struct resource *r;
+	int err;
+
+	chip = platform_get_drvdata(pdev);
+	if (chip == NULL)
+		return -ENODEV;
+
+	err = pwmchip_remove(&chip->chip);
+	if (err < 0)
+		return err;
+
+	iounmap(chip->base);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(r->start, resource_size(r));
+
+	kfree(chip);
+	return 0;
+}
+
+static struct platform_driver pwm_driver = {
+	.driver		= {
+		.name	= "vt8500-pwm",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= pwm_probe,
+	.remove		= __devexit_p(pwm_remove),
+};
+
+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");