/*
* 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>
*/
#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>
#if defined CONFIG_ARCH_MX1 || defined CONFIG_ARCH_MX21
#define PWM_VER_1
#define PWMCR 0x00 /* PWM Control Register */
#define PWMSR 0x04 /* PWM Sample Register */
#define PWMPR 0x08 /* PWM Period Register */
#define PWMCNR 0x0C /* PWM Counter Register */
#define PWMCR_HCTR (1 << 18) /* Halfword FIFO Data Swapping */
#define PWMCR_BCTR (1 << 17) /* Byte FIFO Data Swapping */
#define PWMCR_SWR (1 << 16) /* Software Reset */
#define PWMCR_CLKSRC_PERCLK (0 << 15) /* PERCLK Clock Source */
#define PWMCR_CLKSRC_CLK32 (1 << 15) /* 32KHz Clock Source */
#define PWMCR_PRESCALER(x) (((x - 1) & 0x7F) << 8) /* PRESCALER */
#define PWMCR_IRQ (1 << 7) /* Interrupt Request */
#define PWMCR_IRQEN (1 << 6) /* Interrupt Request Enable */
#define PWMCR_FIFOAV (1 << 5) /* FIFO Available */
#define PWMCR_EN (1 << 4) /* Enables/Disables the PWM */
#define PWMCR_REPEAT(x) (((x) & 0x03) << 2) /* Sample Repeats */
#define PWMCR_DIV(x) (((x) & 0x03) << 0) /* Clock divider 2/4/8/16 */
#define MAX_DIV (128 * 16)
#endif
#if defined CONFIG_MACH_MX27 || defined CONFIG_ARCH_MX31
#define PWM_VER_2
#define PWMCR 0x00 /* PWM Control Register */
#define PWMSR 0x04 /* PWM Status Register */
#define PWMIR 0x08 /* PWM Interrupt Register */
#define PWMSAR 0x0C /* PWM Sample Register */
#define PWMPR 0x10 /* PWM Period Register */
#define PWMCNR 0x14 /* PWM Counter Register */
#define PWMCR_EN (1 << 0) /* Enables/Disables the PWM */
#define PWMCR_REPEAT(x) (((x) & 0x03) << 1) /* Sample Repeats */
#define PWMCR_SWR (1 << 3) /* Software Reset */
#define PWMCR_PRESCALER(x) (((x - 1) & 0xFFF) << 4)/* PRESCALER */
#define PWMCR_CLKSRC(x) (((x) & 0x3) << 16)
#define PWMCR_CLKSRC_OFF (0 << 16)
#define PWMCR_CLKSRC_IPG (1 << 16)
#define PWMCR_CLKSRC_IPG_HIGH (2 << 16)
#define PWMCR_CLKSRC_CLK32 (3 << 16)
#define PWMCR_POUTC
#define PWMCR_HCTR (1 << 20) /* Halfword FIFO Data Swapping */
#define PWMCR_BCTR (1 << 21) /* Byte FIFO Data Swapping */
#define PWMCR_DBGEN (1 << 22) /* Debug Mode */
#define PWMCR_WAITEN (1 << 23) /* Wait Mode */
#define PWMCR_DOZEN (1 << 24) /* Doze Mode */
#define PWMCR_STOPEN (1 << 25) /* Stop Mode */
#define PWMCR_FWM(x) (((x) & 0x3) << 26) /* FIFO Water Mark */
#define MAX_DIV 4096
#endif
#define PWMS_SAMPLE(x) ((x) & 0xFFFF) /* Contains a two-sample word */
#define PWMP_PERIOD(x) ((x) & 0xFFFF) /* Represents the PWM's period */
#define PWMC_COUNTER(x) ((x) & 0xFFFF) /* Represents the current count value */
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 pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
unsigned long long c;
unsigned long period_cycles, duty_cycles, prescale;
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;
prescale = period_cycles / 0x10000 + 1;
period_cycles /= prescale;
c = (unsigned long long)period_cycles * duty_ns;
do_div(c, period_ns);
duty_cycles = c;
#ifdef PWM_VER_2
writel(duty_cycles, pwm->mmio_base + PWMSAR);
writel(period_cycles, pwm->mmio_base + PWMPR);
writel(PWMCR_PRESCALER(prescale - 1) | PWMCR_CLKSRC_IPG_HIGH | PWMCR_EN,
pwm->mmio_base + PWMCR);
#elif defined PWM_VER_1
#error PWM not yet working on MX1 / MX21
#endif
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 int __devinit mxc_pwm_probe(struct platform_device *pdev)
{
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 -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;
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>");
