On 02/14/2017 05:23 AM, Marco Franchi wrote:
Allow the driver to work with device tree support.
Based on initial patch submission from Peter Fox.
Tested on a imx7d-sdb board connected to a SHT15 board via Mikro Bus.
Signed-off-by: Marco Franchi <marco.franchi@xxxxxxx>
---
Changes since v1:
- reworked to not require int returns in the sht15_probe_dt function;
- add a clear preference for dt or platform data
- Use 'device tree' instead of 'dts' in the Subject
Documentation/devicetree/bindings/hwmon/sht15.txt | 25 +++++++++
drivers/hwmon/sht15.c | 66 +++++++++++++++++++++--
2 files changed, 87 insertions(+), 4 deletions(-)
create mode 100644 Documentation/devicetree/bindings/hwmon/sht15.txt
diff --git a/Documentation/devicetree/bindings/hwmon/sht15.txt b/Documentation/devicetree/bindings/hwmon/sht15.txt
new file mode 100644
index 0000000..6415f52
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/sht15.txt
@@ -0,0 +1,25 @@
+Sensirion SHT15 Humidity and Temperature Sensor
+
+Required properties:
+
+ - "compatible": must be "sensirion,sht15".
+ - "data-gpios": GPIO connected to the data line.
+ - "clk-gpios": GPIO connected to the clock line.
+ - "vcc-supply": regulator that drives the VCC pin.
+
+Optional properties:
+
+ - "checksum": boolean property that when present enables the CRC validation of the readings.
+ - "no-otp-reload": boolean property that when present indicates not to reload from OTP.
+ - "low-resolution": boolean property that when present indicates that the device operates in
+ low-resolution mode.
+Example:
+
+ temp_humid_sensor: sht15 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_sensor>;
+ compatible = "sensirion,sht15";
+ clk-gpios = <&gpio4 12 0>;
+ data-gpios = <&gpio4 13 0>;
+ vcc-supply = <®_sht15>;
+ };
diff --git a/drivers/hwmon/sht15.c b/drivers/hwmon/sht15.c
index f16687c..70906f1 100644
--- a/drivers/hwmon/sht15.c
+++ b/drivers/hwmon/sht15.c
@@ -34,6 +34,7 @@
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/bitrev.h>
+#include <linux/of_gpio.h>
/* Commands */
#define SHT15_MEASURE_TEMP 0x03
@@ -911,6 +912,56 @@ static int sht15_invalidate_voltage(struct notifier_block *nb,
return NOTIFY_OK;
}
+#ifdef CONFIG_OF
+static const struct of_device_id sht15_dt_match[] = {
+ { .compatible = "sensirion,sht15" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, sht15_dt_match);
+
+/*
+ * This function returns NULL if pdev isn't a device instatiated by dt,
+ * a pointer to the data if it could successfully get all information
+ * from dt or a negative error number.
+ */
+static struct sht15_platform_data *sht15_probe_dt(struct device *dev)
+{
+ struct device_node *np = dev->of_node;
+ struct sht15_platform_data *pdata;
+
+ /* no device tree device */
+ if (!np)
+ return NULL;
+
+ pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return ERR_PTR(-ENOMEM);
+
+ pdata->gpio_data = of_get_named_gpio(np, "data-gpios", 0);
+ if (pdata->gpio_data < 0) {
+ dev_err(dev, "data-gpios not found\n");
+ return ERR_PTR(-EINVAL);
Never replace an error return value with a different one. The called function
could return -EPROBE_DEFER, which you would want to have returned to the caller.
In that case, you would also not want to see an error message.
+ }
+
+ pdata->gpio_sck = of_get_named_gpio(np, "clk-gpios", 0);
+ if (pdata->gpio_sck < 0) {
+ dev_err(dev, "clk-gpios not found\n");
+ return ERR_PTR(-EINVAL);
Same here.
+ }
+
+ pdata->checksum = of_property_read_bool(np, "checksum");
+ pdata->no_otp_reload = of_property_read_bool(np, "no-otp-reload");
+ pdata->low_resolution = of_property_read_bool(np, "low-resolution");
+
+ return pdata;
+}
+#else
+static inline struct sht15_platform_data *sht15_probe_dt(struct device *dev)
+{
+ return NULL;
+}
+#endif
+
static int sht15_probe(struct platform_device *pdev)
{
int ret;
@@ -928,11 +979,17 @@ static int sht15_probe(struct platform_device *pdev)
data->dev = &pdev->dev;
init_waitqueue_head(&data->wait_queue);
- if (dev_get_platdata(&pdev->dev) == NULL) {
- dev_err(&pdev->dev, "no platform data supplied\n");
- return -EINVAL;
+ data->pdata = sht15_probe_dt(&pdev->dev);
+ if (IS_ERR(data->pdata))
+ return PTR_ERR(data->pdata);
+ if (data->pdata == NULL) {
+ data->pdata = dev_get_platdata(&pdev->dev);
+ if (data->pdata == NULL) {
+ dev_err(&pdev->dev, "no platform data supplied\n");
+ return -EINVAL;
+ }
}
- data->pdata = dev_get_platdata(&pdev->dev);
+
data->supply_uv = data->pdata->supply_mv * 1000;
if (data->pdata->checksum)
data->checksumming = true;
@@ -1075,6 +1132,7 @@ MODULE_DEVICE_TABLE(platform, sht15_device_ids);
static struct platform_driver sht15_driver = {
.driver = {
.name = "sht15",
+ .of_match_table = of_match_ptr(sht15_dt_match),
},
.probe = sht15_probe,
.remove = sht15_remove,
--
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