1 files changed, 265 insertions, 0 deletions

diff --git a/arch/arm/mach-vt8500/pwm.c b/arch/arm/mach-vt8500/pwm.c
new file mode 100644
index 000000000000..8ad825e93592
--- /dev/null
+++ b/arch/arm/mach-vt8500/pwm.c
@@ -0,0 +1,265 @@
+/*
+ * 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
+
+static DEFINE_MUTEX(pwm_lock);
+static LIST_HEAD(pwm_list);
+
+struct pwm_device {
+        struct list_head        node;
+        struct platform_device  *pdev;
+
+        const char      *label;
+
+        void __iomem    *regbase;
+
+        unsigned int    use_count;
+        unsigned int    pwm_id;
+};
+
+#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);
+}
+
+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 = 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(pwm->regbase + 0x40 + pwm->pwm_id, (1 << 1));
+        writel(prescale, pwm->regbase + 0x4 + (pwm->pwm_id << 4));
+
+        pwm_busy_wait(pwm->regbase + 0x40 + pwm->pwm_id, (1 << 2));
+        writel(pv, pwm->regbase + 0x8 + (pwm->pwm_id << 4));
+
+        pwm_busy_wait(pwm->regbase + 0x40 + pwm->pwm_id, (1 << 3));
+        writel(dc, pwm->regbase + 0xc + (pwm->pwm_id << 4));
+
+        return 0;
+}
+EXPORT_SYMBOL(pwm_config);
+
+int pwm_enable(struct pwm_device *pwm)
+{
+        pwm_busy_wait(pwm->regbase + 0x40 + pwm->pwm_id, (1 << 0));
+        writel(5, pwm->regbase + (pwm->pwm_id << 4));
+        return 0;
+}
+EXPORT_SYMBOL(pwm_enable);
+
+void pwm_disable(struct pwm_device *pwm)
+{
+        pwm_busy_wait(pwm->regbase + 0x40 + pwm->pwm_id, (1 << 0));
+        writel(0, pwm->regbase + (pwm->pwm_id << 4));
+}
+EXPORT_SYMBOL(pwm_disable);
+
+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 pwm_device *pwms;
+        struct resource *r;
+        int ret = 0;
+        int i;
+
+        pwms = kzalloc(sizeof(struct pwm_device) * VT8500_NR_PWMS, GFP_KERNEL);
+        if (pwms == NULL) {
+                dev_err(&pdev->dev, "failed to allocate memory\n");
+                return -ENOMEM;
+        }
+
+        for (i = 0; i < VT8500_NR_PWMS; i++) {
+                pwms[i].use_count = 0;
+                pwms[i].pwm_id = i;
+                pwms[i].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;
+        }
+
+        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;
+        }
+
+        pwms[0].regbase = ioremap(r->start, resource_size(r));
+        if (pwms[0].regbase == NULL) {
+                dev_err(&pdev->dev, "failed to ioremap() registers\n");
+                ret = -ENODEV;
+                goto err_free_mem;
+        }
+
+        for (i = 1; i < VT8500_NR_PWMS; i++)
+                pwms[i].regbase = pwms[0].regbase;
+
+        for (i = 0; i < VT8500_NR_PWMS; i++)
+                __add_pwm(&pwms[i]);
+
+        platform_set_drvdata(pdev, pwms);
+        return 0;
+
+err_free_mem:
+        release_mem_region(r->start, resource_size(r));
+err_free:
+        kfree(pwms);
+        return ret;
+}
+
+static int __devexit pwm_remove(struct platform_device *pdev)
+{
+        struct pwm_device *pwms;
+        struct resource *r;
+        int i;
+
+        pwms = platform_get_drvdata(pdev);
+        if (pwms == NULL)
+                return -ENODEV;
+
+        mutex_lock(&pwm_lock);
+
+        for (i = 0; i < VT8500_NR_PWMS; i++)
+                list_del(&pwms[i].node);
+        mutex_unlock(&pwm_lock);
+
+        iounmap(pwms[0].regbase);
+
+        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        release_mem_region(r->start, resource_size(r));
+
+        kfree(pwms);
+        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");