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>

3 files changed, 218 insertions, 0 deletions

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 0d9aa92636c3..a93feffbc36a 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -55,4 +55,13 @@ config PWM_TEGRA
           To compile this driver as a module, choose M here: the module
           will be called pwm-tegra.
 
+config PWM_VT8500
+        tristate "vt8500 pwm support"
+        depends on ARCH_VT8500
+        help
+          Generic PWM framework driver for vt8500.
+
+          To compile this driver as a module, choose M here: the module
+          will be called pwm-vt8500.
+
 endif
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index a1d87b173312..b7c0fcf4de16 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_PWM_IMX)		+= pwm-imx.o
 obj-$(CONFIG_PWM_PXA)           += pwm-pxa.o
 obj-$(CONFIG_PWM_SAMSUNG)       += pwm-samsung.o
 obj-$(CONFIG_PWM_TEGRA)         += pwm-tegra.o
+obj-$(CONFIG_PWM_VT8500)        += pwm-vt8500.o
diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c
new file mode 100644
index 000000000000..3db0746f7200
--- /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");