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|
--- a/arch/arm/plat-mxc/pwm.c
+++ b/arch/arm/plat-mxc/pwm.c
@@ -25,6 +25,11 @@
#define MX1_PWMS 0x04 /* PWM Sample Register */
#define MX1_PWMP 0x08 /* PWM Period Register */
+#define MX1_PWMC_EN (1 << 4)
+#define MX1_PWMC_PRESCALER_MASK (0x7f << 8)
+#define MX1_PWMC_PRESCALER(x) ((x & 0x7f) << 8)
+#define MX1_PWMC_CLKSEL_MASK 0x3
+#define MX1_PWMC_CLKSEL(x) ((x & 0x3))
/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */
@@ -54,26 +59,33 @@ struct pwm_device {
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;
+
+ if (cpu_is_mx1() || cpu_is_mx2())
+ c >>= 1;
+
+ 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;
+
+
if (cpu_is_mx27() || cpu_is_mx3() || cpu_is_mx25()) {
- 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);
@@ -86,25 +98,28 @@ int pwm_config(struct pwm_device *pwm, i
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);
+ unsigned long clksel = 0;
+ u32 ctrl;
+
+ while (prescale >= 0x80 && clksel < 4) {
+ prescale >>= 1;
+ ++clksel;
+ }
+
+ if (clksel > 3)
+ return -EINVAL;
+
+ ctrl = readl(pwm->mmio_base + MX1_PWMC);
+ writel(ctrl & ~MX1_PWMC_EN, pwm->mmio_base + MX1_PWMC);
+
+ writel(duty_cycles, pwm->mmio_base + MX1_PWMS);
+ writel(period_cycles, pwm->mmio_base + MX1_PWMP);
+
+ ctrl &= ~(MX1_PWMC_PRESCALER_MASK | MX1_PWMC_CLKSEL_MASK);
+ ctrl |= MX1_PWMC_PRESCALER(prescale);
+ ctrl |= MX1_PWMC_CLKSEL(clksel);
+ writel(ctrl, pwm->mmio_base + MX1_PWMC);
+
} else {
BUG();
}
@@ -116,6 +131,11 @@ EXPORT_SYMBOL(pwm_config);
int pwm_enable(struct pwm_device *pwm)
{
int rc = 0;
+ if (cpu_is_mx1() || cpu_is_mx2()) {
+ u32 ctrl;
+ ctrl = readl(pwm->mmio_base + MX1_PWMC);
+ writel(ctrl | MX1_PWMC_EN, pwm->mmio_base + MX1_PWMC);
+ }
if (!pwm->clk_enabled) {
rc = clk_enable(pwm->clk);
@@ -128,7 +148,13 @@ EXPORT_SYMBOL(pwm_enable);
void pwm_disable(struct pwm_device *pwm)
{
- writel(0, pwm->mmio_base + MX3_PWMCR);
+ if (cpu_is_mx27() || cpu_is_mx3() || cpu_is_mx25()) {
+ writel(0, pwm->mmio_base + MX3_PWMCR);
+ } else if (cpu_is_mx1() || cpu_is_mx2()) {
+ u32 ctrl;
+ ctrl = readl(pwm->mmio_base + MX1_PWMC);
+ writel(ctrl & ~MX1_PWMC_EN, pwm->mmio_base + MX1_PWMC);
+ }
if (pwm->clk_enabled) {
clk_disable(pwm->clk);
|
