pwm, imx6: add support for pwm modul on imx6

[karo-tx-uboot.git] / drivers / pwm / pwm-imx-util.c

diff --git a/drivers/pwm/pwm-imx-util.c b/drivers/pwm/pwm-imx-util.c
new file mode 100644 (file)
index 0000000..f1d0b35
--- /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;
+}