linux/arch/arm/plat-mxc/pwm.c

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/*
* 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 cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pwm.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_CLKSRC_IPG_HIGH (2 << 16)
#define MX3_PWMCR_CLKSRC_IPG (1 << 16)
#define MX3_PWMCR_EN (1 << 0)
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)
{
if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
return -EINVAL;
if (cpu_is_mx27() || cpu_is_mx3() || cpu_is_mx25() || cpu_is_mx51()) {
unsigned long long c;
unsigned long period_cycles, duty_cycles, prescale;
u32 cr;
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;
writel(duty_cycles, pwm->mmio_base + MX3_PWMSAR);
writel(period_cycles, pwm->mmio_base + MX3_PWMPR);
cr = MX3_PWMCR_PRESCALER(prescale) | MX3_PWMCR_EN;
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 = 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)
{
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)
{
writel(0, pwm->mmio_base + MX3_PWMCR);
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>");