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-rwxr-xr-xarch/arm/plat-mxc/pwm.c343
1 files changed, 343 insertions, 0 deletions
diff --git a/arch/arm/plat-mxc/pwm.c b/arch/arm/plat-mxc/pwm.c
new file mode 100755
index 00000000..eb490571
--- /dev/null
+++ b/arch/arm/plat-mxc/pwm.c
@@ -0,0 +1,343 @@
+/*
+ * 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.
+ *
+ * Derived from pxa PWM driver by eric miao <eric.miao@marvell.com>
+ * Copyright 2009-2013 Freescale Semiconductor, Inc. All Rights Reserved.
+ */
+
+#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 <linux/fsl_devices.h>
+#include <mach/hardware.h>
+
+
+/* i.MX1 and i.MX21 share the same PWM function block: */
+
+#define MX1_PWMC 0x00 /* PWM Control Register */
+#define MX1_PWMS 0x04 /* PWM Sample Register */
+#define MX1_PWMP 0x08 /* PWM Period Register */
+
+
+/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */
+
+#define MX3_PWMCR 0x00 /* PWM Control Register */
+#define MX3_PWMSAR 0x0C /* PWM Sample Register */
+#define MX3_PWMPR 0x10 /* PWM Period Register */
+#define MX3_PWMCR_PRESCALER(x) (((x - 1) & 0xFFF) << 4)
+#define MX3_PWMCR_DOZEEN (1 << 24)
+#define MX3_PWMCR_WAITEN (1 << 23)
+#define MX3_PWMCR_DBGEN (1 << 22)
+#define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16)
+#define MX3_PWMCR_CLKSRC_IPG (1 << 16)
+#define MX3_PWMCR_SWR (1 << 3)
+#define MX3_PWMCR_EN (1 << 0)
+
+#define MX3_PWMCR_STOPEN (1 << 25)
+#define MX3_PWMCR_DOZEEN (1 << 24)
+#define MX3_PWMCR_WAITEN (1 << 23)
+#define MX3_PWMCR_DBGEN (1 << 22)
+#define MX3_PWMCR_CLKSRC_IPG (1 << 16)
+#define MX3_PWMCR_CLKSRC_IPG_32k (3 << 16)
+
+struct pwm_device {
+ struct list_head node;
+ 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;
+ int pwmo_invert;
+ void (*enable_pwm_pad)(void);
+ void (*disable_pwm_pad)(void);
+};
+
+int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
+{
+ if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
+ return -EINVAL;
+
+ if (!(cpu_is_mx1() || cpu_is_mx21())) {
+ unsigned long long c;
+ unsigned long period_cycles, duty_cycles, prescale;
+ u32 cr;
+
+ if (pwm->pwmo_invert)
+ duty_ns = period_ns - duty_ns;
+
+ c = clk_get_rate(pwm->clk);
+ c = c * period_ns;
+ do_div(c, 1000000000);
+ period_cycles = c;
+
+ prescale = period_cycles / 0x10000 + 1;
+
+ period_cycles /= prescale;
+ c = (unsigned long long)period_cycles * duty_ns;
+ do_div(c, period_ns);
+ duty_cycles = c;
+
+ /*
+ * according to imx pwm RM, the real period value should be
+ * PERIOD value in PWMPR plus 2.
+ */
+ if (period_cycles > 2)
+ period_cycles -= 2;
+ else
+ period_cycles = 0;
+
+ writel(duty_cycles, pwm->mmio_base + MX3_PWMSAR);
+ writel(period_cycles, pwm->mmio_base + MX3_PWMPR);
+
+ cr = MX3_PWMCR_PRESCALER(prescale) |
+ MX3_PWMCR_STOPEN | MX3_PWMCR_DOZEEN |
+ MX3_PWMCR_WAITEN | MX3_PWMCR_DBGEN;
+
+ if (cpu_is_mx25())
+ cr |= MX3_PWMCR_CLKSRC_IPG;
+ else
+ cr |= MX3_PWMCR_CLKSRC_IPG_HIGH;
+
+ writel(cr, pwm->mmio_base + MX3_PWMCR);
+ } else if (cpu_is_mx1() || cpu_is_mx21()) {
+ /* The PWM subsystem allows for exact frequencies. However,
+ * I cannot connect a scope on my device to the PWM line and
+ * thus cannot provide the program the PWM controller
+ * exactly. Instead, I'm relying on the fact that the
+ * Bootloader (u-boot or WinCE+haret) has programmed the PWM
+ * function group already. So I'll just modify the PWM sample
+ * register to follow the ratio of duty_ns vs. period_ns
+ * accordingly.
+ *
+ * This is good enough for programming the brightness of
+ * the LCD backlight.
+ *
+ * The real implementation would divide PERCLK[0] first by
+ * both the prescaler (/1 .. /128) and then by CLKSEL
+ * (/2 .. /16).
+ */
+ u32 max = readl(pwm->mmio_base + MX1_PWMP);
+ u32 p;
+ if (pwm->pwmo_invert)
+ duty_ns = period_ns - duty_ns;
+ p = max * duty_ns / period_ns;
+ writel(max - p, pwm->mmio_base + MX1_PWMS);
+ } else {
+ BUG();
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(pwm_config);
+
+int pwm_enable(struct pwm_device *pwm)
+{
+ unsigned long reg;
+ int rc = 0;
+
+ if (!pwm->clk_enabled) {
+ rc = clk_enable(pwm->clk);
+ if (!rc)
+ pwm->clk_enabled = 1;
+ }
+
+ reg = readl(pwm->mmio_base + MX3_PWMCR);
+ reg |= MX3_PWMCR_EN;
+ writel(reg, pwm->mmio_base + MX3_PWMCR);
+
+ if (pwm->enable_pwm_pad)
+ pwm->enable_pwm_pad();
+
+ return rc;
+}
+EXPORT_SYMBOL(pwm_enable);
+
+void pwm_disable(struct pwm_device *pwm)
+{
+ if (pwm->disable_pwm_pad)
+ pwm->disable_pwm_pad();
+
+ writel(MX3_PWMCR_SWR, pwm->mmio_base + MX3_PWMCR);
+ while (readl(pwm->mmio_base + MX3_PWMCR) & MX3_PWMCR_SWR)
+ ;
+
+ 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 int __devinit mxc_pwm_probe(struct platform_device *pdev)
+{
+ struct pwm_device *pwm;
+ struct resource *r;
+ struct mxc_pwm_platform_data *plat_data = pdev->dev.platform_data;
+ 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, "pwm");
+
+ if (IS_ERR(pwm->clk)) {
+ ret = PTR_ERR(pwm->clk);
+ goto err_free;
+ }
+
+ pwm->clk_enabled = 0;
+
+ pwm->use_count = 0;
+ pwm->pwm_id = pdev->id;
+ pwm->pdev = pdev;
+ if (plat_data != NULL) {
+ pwm->pwmo_invert = plat_data->pwmo_invert;
+ pwm->enable_pwm_pad = plat_data->enable_pwm_pad;
+ pwm->disable_pwm_pad = plat_data->disable_pwm_pad;
+ }
+
+ 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;
+ }
+
+ mutex_lock(&pwm_lock);
+ list_add_tail(&pwm->node, &pwm_list);
+ mutex_unlock(&pwm_lock);
+
+ platform_set_drvdata(pdev, pwm);
+ return 0;
+
+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 ret;
+}
+
+static int __devexit mxc_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 mxc_pwm_driver = {
+ .driver = {
+ .name = "mxc_pwm",
+ },
+ .probe = mxc_pwm_probe,
+ .remove = __devexit_p(mxc_pwm_remove),
+};
+
+static int __init mxc_pwm_init(void)
+{
+ return platform_driver_register(&mxc_pwm_driver);
+}
+arch_initcall(mxc_pwm_init);
+
+static void __exit mxc_pwm_exit(void)
+{
+ platform_driver_unregister(&mxc_pwm_driver);
+}
+module_exit(mxc_pwm_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-09 10:40:52 +0000