Enabling PWM on TMS320C6A8168 with Linux 2.6.37

I figured it out:

Create a kernel module and use arch/arm/plat-omap/dmtimer.h 

Example code below to create a 4KHz 50/50 PWM output.

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <plat/dmtimer.h>
#include <linux/types.h>

MODULE_AUTHOR("Ulf Tisting <ulf@svep.se>");
MODULE_DESCRIPTION("TI816xx PWM module");
MODULE_LICENSE("GPL");

#define SPEAKER_TIMER_ID 6

// pointer to timer object
static struct omap_dm_timer *timer_ptr;

// initialize the kernel module
static int __init pwm_init(void)
{
struct clk *gt_fclk;
uint32_t gt_rate;

// request the GPT6-timer (speaker output)
timer_ptr = omap_dm_timer_request_specific(SPEAKER_TIMER_ID);
if(timer_ptr == NULL){
printk("PWM module : timer connected to speaker unavailable, bailing out\n");
return -1;
}

// set the clock source to system clock
omap_dm_timer_set_source(timer_ptr, OMAP_TIMER_SRC_SYS_CLK);

// set prescalar to 1:1
omap_dm_timer_set_prescaler(timer_ptr, 0);

// get clock rate in Hz
gt_fclk = omap_dm_timer_get_fclk(timer_ptr);
gt_rate = clk_get_rate(gt_fclk);

// setup Timer Control Register (TCLR) for PWM (SCPWM=1, PT=1, TRG=1)
omap_dm_timer_set_pwm(timer_ptr, 1, 1, 1);

// set Timer Load Register (TLDR) to 4KHz (AR=1)
omap_dm_timer_set_load(timer_ptr, 1, 0xFFFFFFFF - (gt_rate/250));

// start the timer!
omap_dm_timer_start(timer_ptr);

// debug printout
printk("PWM module : GP Timer initialized and started (%lu Hz)\n",\
(long unsigned)gt_rate);

// return success
return 0;

}

// cleanup
static void __exit pwm_exit(void)
{
printk("PWM module : cleanup called\n");

// stop the timer
omap_dm_timer_stop(timer_ptr);

// release the timer
omap_dm_timer_free(timer_ptr);
}

// provide the kernel with the entry/exit routines
module_init(pwm_init);
module_exit(pwm_exit);