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authorAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
committerAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /arch/arm/plat-pxa/pwm.c
parentedd4be777c953e5faafc80d091d3084b4343f5d3 (diff)
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'arch/arm/plat-pxa/pwm.c')
-rw-r--r--arch/arm/plat-pxa/pwm.c304
1 files changed, 304 insertions, 0 deletions
diff --git a/arch/arm/plat-pxa/pwm.c b/arch/arm/plat-pxa/pwm.c
new file mode 100644
index 00000000000..ef32686feef
--- /dev/null
+++ b/arch/arm/plat-pxa/pwm.c
@@ -0,0 +1,304 @@
+/*
+ * 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/slab.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)
+{
+ const 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, resource_size(r), 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, resource_size(r));
+ 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, resource_size(r));
+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, resource_size(r));
+
+ 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");