pwm, imx6: add support for pwm modul on imx6

add basic support for the pwm modul found on imx6.
Pieces of this code are based on linux code from drivers/pwm/pwm-imx.c
Commit "cd3de83f1476 Linux 3.16-rc4"

Signed-off-by: Heiko Schocher <hs@denx.de>
Acked-by: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>

1 files changed, 73 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-imx-util.c b/drivers/pwm/pwm-imx-util.c
new file mode 100644
index 0000000000..f1d0b35d27
--- /dev/null
+++ b/drivers/pwm/pwm-imx-util.c
@@ -0,0 +1,73 @@
+/*
+ * (C) Copyright 2014
+ * Heiko Schocher, DENX Software Engineering, hs@denx.de.
+ *
+ * Basic support for the pwm modul on imx6.
+ *
+ * Based on linux:drivers/pwm/pwm-imx.c
+ * from
+ * Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <common.h>
+#include <div64.h>
+#include <asm/arch/imx-regs.h>
+
+/* pwm_id from 0..3 */
+struct pwm_regs *pwm_id_to_reg(int pwm_id)
+{
+	switch (pwm_id) {
+	case 0:
+		return (struct pwm_regs *)PWM1_BASE_ADDR;
+		break;
+	case 1:
+		return (struct pwm_regs *)PWM2_BASE_ADDR;
+		break;
+	case 2:
+		return (struct pwm_regs *)PWM3_BASE_ADDR;
+		break;
+	case 3:
+		return (struct pwm_regs *)PWM4_BASE_ADDR;
+		break;
+	default:
+		printf("unknown pwm_id: %d\n", pwm_id);
+		break;
+	}
+	return NULL;
+}
+
+int pwm_imx_get_parms(int period_ns, int duty_ns, unsigned long *period_c,
+		      unsigned long *duty_c, unsigned long *prescale)
+{
+	unsigned long long c;
+
+	/*
+	 * we have not yet a clock framework for imx6, so add the clock
+	 * value here as a define. Replace it when we have the clock
+	 * framework.
+	 */
+	c = CONFIG_IMX6_PWM_PER_CLK;
+	c = c * period_ns;
+	do_div(c, 1000000000);
+	*period_c = c;
+
+	*prescale = *period_c / 0x10000 + 1;
+
+	*period_c /= *prescale;
+	c = (unsigned long long)(*period_c * duty_ns);
+	do_div(c, period_ns);
+	*duty_c = c;
+
+	/*
+	 * according to imx pwm RM, the real period value should be
+	 * PERIOD value in PWMPR plus 2.
+	 */
+	if (*period_c > 2)
+		*period_c -= 2;
+	else
+		*period_c = 0;
+
+	return 0;
+}