Allow the current for both RED and IR LEDs to be set via an device tree
property setting.
This is an optional setting that is useful for applications that have a
known glass attenuation factor.
Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx>
---
.../devicetree/bindings/iio/health/max30100.txt | 7 +++++++
drivers/iio/health/max30100.c | 21 +++++++++++++++------
2 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/Documentation/devicetree/bindings/iio/health/max30100.txt b/Documentation/devicetree/bindings/iio/health/max30100.txt
index f6fbac6..009314c 100644
--- a/Documentation/devicetree/bindings/iio/health/max30100.txt
+++ b/Documentation/devicetree/bindings/iio/health/max30100.txt
@@ -11,11 +11,18 @@ Required properties:
Refer to interrupt-controller/interrupts.txt for generic
interrupt client node bindings.
+Optional properties:
+ - max30100,led-current: configuration for LED current (in mA) while the engine
+ is running. Upper nibble is for the RED LED, and lower nibble the IR LED.
+
+ Refer to the datasheet for the current mapping values.
+
Example:
max30100@057 {
compatible = "maxim,max30100";
reg = <57>;
+ max30100,led-current = <0x7f>;
interrupt-parent = <&gpio1>;
interrupts = <16 2>;
};
diff --git a/drivers/iio/health/max30100.c b/drivers/iio/health/max30100.c
index 9d1c81f..37e8d7e 100644
--- a/drivers/iio/health/max30100.c
+++ b/drivers/iio/health/max30100.c
@@ -13,7 +13,7 @@
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
- * TODO: allow LED current and pulse length controls via device tree properties
+ * TODO: enable pulse length controls via device tree properties
*/
#include <linux/module.h>
@@ -24,6 +24,7 @@
#include <linux/irq.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
+#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
@@ -245,13 +246,21 @@ static irqreturn_t max30100_interrupt_handler(int irq, void *private)
static int max30100_chip_init(struct max30100_data *data)
{
+ struct device *dev = &data->client->dev;
+ struct device_node *np = dev->of_node;
int ret;
+ u32 val;
- /* RED IR LED = 24mA, IR LED = 50mA */
- ret = regmap_write(data->regmap, MAX30100_REG_LED_CONFIG,
- (MAX30100_REG_LED_CONFIG_24MA <<
- MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
- MAX30100_REG_LED_CONFIG_50MA);
+ ret = of_property_read_u32(np, "max30100,led-current", &val);
+ if (ret) {
+ /* Default to 24 mA RED LED, 50 mA IR LED */
+ val = (MAX30100_REG_LED_CONFIG_24MA <<
+ MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
+ MAX30100_REG_LED_CONFIG_50MA;
+ dev_warn(dev, "no led-current set, defaulting to %d", val);
+ }
+
+ ret = regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, val & 0xFF);
if (ret)
return ret;
--
2.6.4
--
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