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Diffstat (limited to 'arch/arm/mach-pxa/pwm.c')
-rw-r--r--arch/arm/mach-pxa/pwm.c299
1 files changed, 299 insertions, 0 deletions
diff --git a/arch/arm/mach-pxa/pwm.c b/arch/arm/mach-pxa/pwm.c
new file mode 100644
index 00000000000..70fb3ca6a05
--- /dev/null
+++ b/arch/arm/mach-pxa/pwm.c
@@ -0,0 +1,299 @@
+/*
+ * 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>
+#include <asm/arch/pxa-regs.h>
+
+/* 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 platform_device *pdev;
+
+ const char *label;
+ struct clk *clk;
+ 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 < 0)
+ 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)
+{
+ return clk_enable(pwm->clk);
+}
+EXPORT_SYMBOL(pwm_enable);
+
+void pwm_disable(struct pwm_device *pwm)
+{
+ clk_disable(pwm->clk);
+}
+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 && pwm->use_count == 0) {
+ pwm->use_count++;
+ pwm->label = label;
+ found = 1;
+ break;
+ }
+ }
+
+ mutex_unlock(&pwm_lock);
+
+ return (found) ? pwm : NULL;
+}
+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 struct pwm_device *pwm_probe(struct platform_device *pdev,
+ unsigned int pwm_id, struct pwm_device *parent_pwm)
+{
+ struct pwm_device *pwm;
+ 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 ERR_PTR(-ENOMEM);
+ }
+
+ pwm->clk = clk_get(&pdev->dev, "PWMCLK");
+ if (IS_ERR(pwm->clk)) {
+ ret = PTR_ERR(pwm->clk);
+ goto err_free;
+ }
+
+ pwm->use_count = 0;
+ pwm->pwm_id = pwm_id;
+ pwm->pdev = pdev;
+
+ if (parent_pwm != NULL) {
+ /* registers for the second PWM has offset of 0x10 */
+ pwm->mmio_base = parent_pwm->mmio_base + 0x10;
+ __add_pwm(pwm);
+ return pwm;
+ }
+
+ 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;
+ }
+
+ __add_pwm(pwm);
+ platform_set_drvdata(pdev, pwm);
+ return pwm;
+
+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 ERR_PTR(ret);
+}
+
+static int __devinit pxa25x_pwm_probe(struct platform_device *pdev)
+{
+ struct pwm_device *pwm = pwm_probe(pdev, pdev->id, NULL);
+
+ if (IS_ERR(pwm))
+ return PTR_ERR(pwm);
+
+ return 0;
+}
+
+static int __devinit pxa27x_pwm_probe(struct platform_device *pdev)
+{
+ struct pwm_device *pwm;
+
+ pwm = pwm_probe(pdev, pdev->id * 2, NULL);
+ if (IS_ERR(pwm))
+ return PTR_ERR(pwm);
+
+ pwm = pwm_probe(pdev, pdev->id * 2 + 1, pwm);
+ if (IS_ERR(pwm))
+ return PTR_ERR(pwm);
+
+ return 0;
+}
+
+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);
+ 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 pxa25x_pwm_driver = {
+ .driver = {
+ .name = "pxa25x-pwm",
+ },
+ .probe = pxa25x_pwm_probe,
+ .remove = __devexit_p(pwm_remove),
+};
+
+static struct platform_driver pxa27x_pwm_driver = {
+ .driver = {
+ .name = "pxa27x-pwm",
+ },
+ .probe = pxa27x_pwm_probe,
+ .remove = __devexit_p(pwm_remove),
+};
+
+static int __init pwm_init(void)
+{
+ int ret = 0;
+
+ ret = platform_driver_register(&pxa25x_pwm_driver);
+ if (ret) {
+ printk(KERN_ERR "failed to register pxa25x_pwm_driver\n");
+ return ret;
+ }
+
+ ret = platform_driver_register(&pxa27x_pwm_driver);
+ if (ret) {
+ printk(KERN_ERR "failed to register pxa27x_pwm_driver\n");
+ return ret;
+ }
+
+ return ret;
+}
+arch_initcall(pwm_init);
+
+static void __exit pwm_exit(void)
+{
+ platform_driver_unregister(&pxa25x_pwm_driver);
+ platform_driver_unregister(&pxa27x_pwm_driver);
+}
+module_exit(pwm_exit);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-15 19:58:34 +0000