[U-Boot] [PATCH v4 3/6] pwm, imx6: add support for pwm modul on imx6
Heiko Schocher
hs at denx.de
Fri Jul 18 06:07:19 CEST 2014
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 at denx.de>
Acked-by: Stefano Babic <sbabic at denx.de>
Cc: Wolfgang Denk <wd at denx.de>
---
- changes for v3:
new in v3, as Stefano Babic suggested
- changes for v4:
- add Acked-by from Stefano Babic
- add in the commit message the commit ID from linux
on which pieces the code is based.
- add comment from Wolfgang Denk:
- move code which is based from linux into a seperate new file
drivers/pwm/pwm-imx-util.c, so this can be with the GPL-2.0
license, and the code not taken from linux can be in GPL-2.0+
README | 4 +++
drivers/Makefile | 1 +
drivers/pwm/Makefile | 13 +++++++++
drivers/pwm/pwm-imx-util.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/pwm/pwm-imx-util.h | 16 ++++++++++
drivers/pwm/pwm-imx.c | 59 +++++++++++++++++++++++++++++++++++++
6 files changed, 166 insertions(+)
create mode 100644 drivers/pwm/Makefile
create mode 100644 drivers/pwm/pwm-imx-util.c
create mode 100644 drivers/pwm/pwm-imx-util.h
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-$(CONFIG_QE) += qe/
obj-y += memory/
+obj-y += pwm/
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
new file mode 100644
index 0000000..c0c4883
--- /dev/null
+++ b/drivers/pwm/Makefile
@@ -0,0 +1,13 @@
+#
+# (C) Copyright 2006
+# Wolfgang Denk, DENX Software Engineering, wd at denx.de.
+#
+# (C) Copyright 2001
+# Erik Theisen, Wave 7 Optics, etheisen at mindspring.com.
+#
+# SPDX-License-Identifier: GPL-2.0+
+#
+
+#ccflags-y += -DDEBUG
+
+obj-$(CONFIG_PWM_IMX) += pwm-imx.o pwm-imx-util.o
diff --git a/drivers/pwm/pwm-imx-util.c b/drivers/pwm/pwm-imx-util.c
new file mode 100644
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 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 <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;
+}
diff --git a/drivers/pwm/pwm-imx-util.h b/drivers/pwm/pwm-imx-util.h
new file mode 100644
index 0000000..45465c4
--- /dev/null
+++ b/drivers/pwm/pwm-imx-util.h
@@ -0,0 +1,16 @@
+/*
+ * (C) Copyright 2014
+ * Heiko Schocher, DENX Software Engineering, hs at denx.de.
+ *
+ * Basic support for the pwm modul on imx6.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#ifndef _pwm_imx_util_h_
+#define _pwm_imx_util_h_
+
+struct pwm_regs *pwm_id_to_reg(int pwm_id);
+int pwm_imx_get_parms(int period_ns, int duty_ns, unsigned long *period_c,
+ unsigned long *duty_c, unsigned long *prescale);
+#endif
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
new file mode 100644
index 0000000..40bf027
--- /dev/null
+++ b/drivers/pwm/pwm-imx.c
@@ -0,0 +1,59 @@
+/*
+ * (C) Copyright 2014
+ * Heiko Schocher, DENX Software Engineering, hs at denx.de.
+ *
+ * Basic support for the pwm modul on imx6.
+ *
+ * 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>
+#include "pwm-imx-util.h"
+
+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 period_cycles, duty_cycles, prescale;
+ u32 cr;
+
+ pwm_imx_get_parms(period_ns, duty_ns, &period_cycles, &duty_cycles,
+ &prescale);
+
+ 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
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