It's often the case that we would write or read a particular field
in register. With the current soc_component apis, reading a particular
field in register would involve first read the register and then
perform shift operations.
Ex:
to read from a field mask of 0xf0
val = snd_soc_component_read(component, reg);
field = ((val & 0xf0) >> 0x4);
This is sometimes prone to errors and code become less readable!
With this new api we could just do
field = snd_soc_component_read_field(component, reg, 0xf0);
this makes it bit simple, easy to write and less error prone!
This also applies to writing!
There are various places in kernel which provides such field interfaces
however soc_component seems to be missing this.
This patch is inspired by FIELD_GET/FIELD_PREP macros in include/linux/bitfield.h
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
---
include/sound/soc-component.h | 6 ++++
sound/soc/soc-component.c | 62 +++++++++++++++++++++++++++++++++++
2 files changed, 68 insertions(+)
diff --git a/include/sound/soc-component.h b/include/sound/soc-component.h
index 0bce41fefd30..5b47768222b7 100644
--- a/include/sound/soc-component.h
+++ b/include/sound/soc-component.h
@@ -353,6 +353,12 @@ int snd_soc_component_test_bits(struct snd_soc_component *component,
unsigned int reg, unsigned int mask,
unsigned int value);
+unsigned int snd_soc_component_read_field(struct snd_soc_component *component,
+ unsigned int reg, unsigned int mask);
+int snd_soc_component_write_field(struct snd_soc_component *component,
+ unsigned int reg, unsigned int mask,
+ unsigned int val);
+
/* component wide operations */
int snd_soc_component_set_sysclk(struct snd_soc_component *component,
int clk_id, int source,
diff --git a/sound/soc/soc-component.c b/sound/soc/soc-component.c
index 760523382f3c..6bdfc6f61ed6 100644
--- a/sound/soc/soc-component.c
+++ b/sound/soc/soc-component.c
@@ -12,6 +12,7 @@
#include <linux/pm_runtime.h>
#include <sound/soc.h>
+#define __soc_component_field_shift(x) (__builtin_ffs(x) - 1)
#define soc_component_ret(dai, ret) _soc_component_ret(dai, __func__, ret)
static inline int _soc_component_ret(struct snd_soc_component *component,
const char *func, int ret)
@@ -839,6 +840,67 @@ int snd_soc_component_update_bits_async(struct snd_soc_component *component,
}
EXPORT_SYMBOL_GPL(snd_soc_component_update_bits_async);
+/**
+ * snd_soc_component_read_field() - Read register field value
+ * @component: Component to read from
+ * @reg: Register to read
+ * @mask: mask of the register field
+ *
+ * Return: read value of register field.
+ */
+unsigned int snd_soc_component_read_field(struct snd_soc_component *component,
+ unsigned int reg, unsigned int mask)
+{
+ unsigned int val;
+
+ mutex_lock(&component->io_mutex);
+ val = soc_component_read_no_lock(component, reg);
+ if (mask)
+ val = (val & mask) >> __soc_component_field_shift(mask);
+ mutex_unlock(&component->io_mutex);
+
+ return val;
+}
+EXPORT_SYMBOL_GPL(snd_soc_component_read_field);
+
+/**
+ * snd_soc_component_write_field() - write to register field
+ * @component: Component to write to
+ * @reg: Register to write
+ * @mask: mask of the register field to update
+ * @val: value of the field to write
+ *
+ * Return: 1 for change, otherwise 0.
+ */
+int snd_soc_component_write_field(struct snd_soc_component *component,
+ unsigned int reg, unsigned int mask,
+ unsigned int val)
+{
+ unsigned int old, new;
+ int ret = 0;
+ bool change;
+
+ if (!mask)
+ return false;
+
+ mutex_lock(&component->io_mutex);
+
+ old = soc_component_read_no_lock(component, reg);
+
+ val = val << __soc_component_field_shift(mask);
+
+ new = (old & ~mask) | (val & mask);
+
+ change = old != new;
+ if (change)
+ ret = soc_component_write_no_lock(component, reg, new);
+
+ mutex_unlock(&component->io_mutex);
+
+ return change;
+}
+EXPORT_SYMBOL_GPL(snd_soc_component_write_field);
+
/**
* snd_soc_component_async_complete() - Ensure asynchronous I/O has completed
* @component: Component for which to wait
--
2.21.0
