#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_EN (1 << 0)
+
-#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;
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
+ if (cpu_is_mx27() || cpu_is_mx3()) {
+ unsigned long long c;
+ unsigned long period_cycles, duty_cycles, prescale;
+ 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);
+ writel(MX3_PWMCR_PRESCALER(prescale - 1) |
+ MX3_PWMCR_CLKSRC_IPG_HIGH | MX3_PWMCR_EN,
+ 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 enought 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;
}
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
-
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff