[U-Boot] [PATCH v3 3/6] pwm, imx6: add support for pwm modul on imx6

[Heiko Schocher]

add basic support for the pwm modul found on imx6.

Signed-off-by: Heiko Schocher <hs at denx.de>
Cc: Stefano Babic <sbabic at denx.de>

---
- changes for v3:
  new in v3, as Stefano Babic suggested

 README                |   4 ++
 drivers/Makefile      |   1 +
 drivers/pwm/Makefile  |  13 ++++++
 drivers/pwm/pwm-imx.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 127 insertions(+)
 create mode 100644 drivers/pwm/Makefile
 create mode 100644 drivers/pwm/pwm-imx.c

diff --git a/README b/README
index 1eecba6..9f07831 100644
--- a/README
+++ b/README
@@ -1377,6 +1377,10 @@ The following options need to be configured:
 			CONFIG_SH_ETHER_CACHE_WRITEBACK
 			If this option is set, the driver enables cache flush.
 
+- PWM Support:
+		CONFIG_PWM_IMX
+		Support for PWM modul on the imx6.
+
 - TPM Support:
 		CONFIG_TPM
 		Support TPM devices.
diff --git a/drivers/Makefile b/drivers/Makefile
index b23076f..b22b109 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -15,3 +15,4 @@ obj-y += video/
 obj-y += watchdog/
 obj-$(CONFIG_QE) += qe/
 obj-y += memory/
+obj-y += pwm/
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
new file mode 100644
index 0000000..3173e20
--- /dev/null
+++ b/drivers/pwm/Makefile
@@ -0,0 +1,13 @@
+#
+# (C) Copyright 2006
+# Wolfgang Denk, DENX Software Engineering, wd at denx.de.
+#
+# (C) Copyright 2001
+# Erik Theisen, Wave 7 Optics, etheisen at mindspring.com.
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+#ccflags-y += -DDEBUG
+
+obj-$(CONFIG_PWM_IMX) += pwm-imx.o
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
new file mode 100644
index 0000000..c70e150
--- /dev/null
+++ b/drivers/pwm/pwm-imx.c
@@ -0,0 +1,109 @@
+/*
+ * (C) Copyright 2014
+ * Heiko Schocher, DENX Software Engineering, hs at denx.de.
+ *
+ * Basic support for the pwm modul on imx6.
+ *
+ * Based on linux:drivers/pwm/pwm-imx.c
+ * from
+ * Sascha Hauer <s.hauer at pengutronix.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <div64.h>
+#include <pwm.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/io.h>
+
+/* pwm_id from 0..3 */
+static 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_init(int pwm_id, int div, int invert)
+{
+	struct pwm_regs *pwm = (struct pwm_regs *)pwm_id_to_reg(pwm_id);
+
+	writel(0, &pwm->ir);
+	return 0;
+}
+
+int pwm_config(int pwm_id, int duty_ns, int period_ns)
+{
+	struct pwm_regs *pwm = (struct pwm_regs *)pwm_id_to_reg(pwm_id);
+	unsigned long long c;
+	unsigned long period_cycles, duty_cycles, prescale;
+	u32 cr;
+
+	/*
+	 * 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_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;
+
+	/*
+	 * according to imx pwm RM, the real period value should be
+	 * PERIOD value in PWMPR plus 2.
+	 */
+	if (period_cycles > 2)
+		period_cycles -= 2;
+	else
+		period_cycles = 0;
+
+	cr = PWMCR_PRESCALER(prescale) |
+		PWMCR_DOZEEN | PWMCR_WAITEN |
+		PWMCR_DBGEN | PWMCR_CLKSRC_IPG_HIGH;
+
+	writel(cr, &pwm->cr);
+	/* set duty cycles */
+	writel(duty_cycles, &pwm->sar);
+	/* set period cycles */
+	writel(period_cycles, &pwm->pr);
+	return 0;
+}
+
+int pwm_enable(int pwm_id)
+{
+	struct pwm_regs *pwm = (struct pwm_regs *)pwm_id_to_reg(pwm_id);
+
+	setbits_le32(&pwm->cr, PWMCR_EN);
+	return 0;
+}
+
+void pwm_disable(int pwm_id)
+{
+	struct pwm_regs *pwm = (struct pwm_regs *)pwm_id_to_reg(pwm_id);
+
+	clrbits_le32(&pwm->cr, PWMCR_EN);
+}
-- 
1.8.3.1