This patch adds helpers to support device-tree bindings for the generic
PWM API.
Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx>
---
drivers/of/Kconfig | 6 +++
drivers/of/Makefile | 1 +
drivers/of/pwm.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_pwm.h | 41 ++++++++++++++++++++++
include/linux/pwm.h | 4 ++
5 files changed, 140 insertions(+), 0 deletions(-)
create mode 100644 drivers/of/pwm.c
create mode 100644 include/linux/of_pwm.h
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index cac63c9..62a2073 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -47,6 +47,12 @@ config OF_GPIO
help
OpenFirmware GPIO accessors
+config OF_PWM
+ def_bool y
+ depends on PWM
+ help
+ OpenFirmware PWM accessors
+
config OF_I2C
def_tristate I2C
depends on I2C && !SPARC
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index dccb117..c3acf27 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_OF_ADDRESS) += address.o
obj-$(CONFIG_OF_IRQ) += irq.o
obj-$(CONFIG_OF_DEVICE) += device.o platform.o
obj-$(CONFIG_OF_GPIO) += gpio.o
+obj-$(CONFIG_OF_PWM) += pwm.o
obj-$(CONFIG_OF_I2C) += of_i2c.o
obj-$(CONFIG_OF_NET) += of_net.o
obj-$(CONFIG_OF_SPI) += of_spi.o
diff --git a/drivers/of/pwm.c b/drivers/of/pwm.c
new file mode 100644
index 0000000..c0ef302
--- /dev/null
+++ b/drivers/of/pwm.c
@@ -0,0 +1,88 @@
+/*
+ * OF helpers for the PWM API
+ *
+ * Copyright (c) 2011 Avionic Design GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pwm.h>
+
+static int of_pwmchip_is_match(struct pwm_chip *chip, void *data)
+{
+ return chip->of_node == data;
+}
+
+/**
+ * of_node_to_pwmchip() - finds the PWM chip associated with a device node
+ * @np: device node of the PWM chip
+ *
+ * Returns a pointer to the PWM chip associated with the specified device
+ * node or NULL if the device node doesn't represent a PWM chip.
+ */
+struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
+{
+ return pwmchip_find(np, of_pwmchip_is_match);
+}
+
+/**
+ * of_get_named_pwm() - get a PWM number and period to use with the PWM API
+ * @np: device node to get the PWM from
+ * @propname: property name containing PWM specifier(s)
+ * @index: index of the PWM
+ * @period_ns: a pointer to the PWM period (in ns) to fill in
+ *
+ * Returns PWM number to use with the Linux generic PWM API or a negative
+ * error code on failure. If @period_ns is not NULL the function fills in
+ * the value parsed from the period-ns property.
+ */
+int of_get_named_pwm(struct device_node *np, const char *propname,
+ int index, unsigned int *period_ns)
+{
+ struct device_node *pwm_np;
+ const void *pwm_spec;
+ struct pwm_chip *pc;
+ const __be32 *spec;
+ u32 cells;
+ u32 pwm;
+ int ret;
+
+ ret = of_parse_phandles_with_args(np, propname, "#pwm-cells", index,
+ &pwm_np, &pwm_spec);
+ if (ret) {
+ pr_debug("%s(): can't parse pwms property\n", __func__);
+ goto out;
+ }
+
+ pc = of_node_to_pwmchip(pwm_np);
+ if (!pc) {
+ ret = -ENODEV;
+ goto put;
+ }
+
+ ret = of_property_read_u32(pwm_np, "#pwm-cells", &cells);
+ if (ret < 0)
+ goto put;
+
+ spec = (const __be32 *)pwm_spec;
+ pwm = be32_to_cpup(pwm_spec);
+
+ if ((cells > 1) && period_ns)
+ *period_ns = be32_to_cpu(spec[1]);
+
+ ret = pc->base + pwm;
+
+put:
+ of_node_put(pwm_np);
+out:
+ pr_debug("%s() exited with status %d\n", __func__, ret);
+ return ret;
+}
+EXPORT_SYMBOL(of_get_named_pwm);
diff --git a/include/linux/of_pwm.h b/include/linux/of_pwm.h
new file mode 100644
index 0000000..8d6d569
--- /dev/null
+++ b/include/linux/of_pwm.h
@@ -0,0 +1,41 @@
+/*
+ * OF helpers for the PWM API
+ *
+ * Copyright (c) 2011 Avionic Design GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __LINUX_OF_PWM_H
+#define __LINUX_OF_PWM_H
+
+#include <linux/pwm.h>
+
+struct device_node;
+
+#ifdef CONFIG_OF_PWM
+
+struct pwm_chip *of_node_to_pwmchip(struct device_node *np);
+int of_get_named_pwm(struct device_node *np, const char *propname,
+ int index, unsigned int *period_ns);
+
+#else
+
+static inline struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
+{
+ return NULL;
+}
+
+static inline int of_get_named_pwm(struct device_node *np,
+ const char *propname, int index,
+ unsigned int *period_ns)
+{
+ return -ENOSYS;
+}
+
+#endif /* CONFIG_OF_PWM */
+
+#endif /* __LINUX_OF_PWM_H */
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 01c0153..d6be4e4 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -65,6 +65,10 @@ struct pwm_chip {
struct pwm_ops *ops;
int base;
unsigned int npwm;
+
+#ifdef CONFIG_OF_PWM
+ struct device_node *of_node;
+#endif
};
int pwmchip_add(struct pwm_chip *chip);
--
1.7.8
--
To unsubscribe from this list: send the line "unsubscribe linux-tegra" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
