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Subject[PATCH v3 1/3] hwmon: (mcp3021) add devicetree support
Date
Support setting the reference voltage from the device tree.

Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
---
drivers/hwmon/mcp3021.c | 46 ++++++++++++++++++++++++++++++++++++----------
1 file changed, 36 insertions(+), 10 deletions(-)

diff --git a/drivers/hwmon/mcp3021.c b/drivers/hwmon/mcp3021.c
index 972444a..81f4b7f 100644
--- a/drivers/hwmon/mcp3021.c
+++ b/drivers/hwmon/mcp3021.c
@@ -4,6 +4,7 @@
* Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
* Author: Mingkai Hu <Mingkai.hu@freescale.com>
* Reworked by Sven Schuchmann <schuchmann@schleissheimer.de>
+ * Copyright (C) 2016 Clemens Gruber <clemens.gruber@pqgruber.com>
*
* This driver export the value of analog input voltage to sysfs, the
* voltage unit is mV. Through the sysfs interface, lm-sensors tool
@@ -22,11 +23,13 @@
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/of_device.h>

-/* Vdd info */
+/* Vdd / reference voltage in millivolt */
#define MCP3021_VDD_MAX 5500
#define MCP3021_VDD_MIN 2700
-#define MCP3021_VDD_REF 3300
+#define MCP3021_VDD_DEFAULT 3300

/* output format */
#define MCP3021_SAR_SHIFT 2
@@ -47,7 +50,7 @@ enum chips {
*/
struct mcp3021_data {
struct device *hwmon_dev;
- u32 vdd; /* device power supply */
+ u32 vdd; /* supply and reference voltage in millivolt */
u16 sar_shift;
u16 sar_mask;
u8 output_res;
@@ -106,6 +109,7 @@ static int mcp3021_probe(struct i2c_client *client,
{
int err;
struct mcp3021_data *data = NULL;
+ struct device_node *np = client->dev.of_node;

if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
@@ -117,6 +121,21 @@ static int mcp3021_probe(struct i2c_client *client,

i2c_set_clientdata(client, data);

+ if (np) {
+ if (of_property_read_u32(np, "reference-voltage-microvolt",
+ &data->vdd))
+ data->vdd = MCP3021_VDD_DEFAULT;
+ else
+ data->vdd /= 1000;
+ } else {
+ u32 *pdata = dev_get_platdata(&client->dev);
+
+ if (pdata)
+ data->vdd = *pdata;
+ else
+ data->vdd = MCP3021_VDD_DEFAULT;
+ }
+
switch (id->driver_data) {
case mcp3021:
data->sar_shift = MCP3021_SAR_SHIFT;
@@ -129,15 +148,12 @@ static int mcp3021_probe(struct i2c_client *client,
data->sar_mask = MCP3221_SAR_MASK;
data->output_res = MCP3221_OUTPUT_RES;
break;
+ default:
+ return -ENODEV;
}

- if (dev_get_platdata(&client->dev)) {
- data->vdd = *(u32 *)dev_get_platdata(&client->dev);
- if (data->vdd > MCP3021_VDD_MAX || data->vdd < MCP3021_VDD_MIN)
- return -EINVAL;
- } else {
- data->vdd = MCP3021_VDD_REF;
- }
+ if (data->vdd > MCP3021_VDD_MAX || data->vdd < MCP3021_VDD_MIN)
+ return -EINVAL;

err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
if (err)
@@ -173,9 +189,19 @@ static const struct i2c_device_id mcp3021_id[] = {
};
MODULE_DEVICE_TABLE(i2c, mcp3021_id);

+#ifdef CONFIG_OF
+static const struct of_device_id of_mcp3021_match[] = {
+ { .compatible = "microchip,mcp3021", .data = (void *)mcp3021 },
+ { .compatible = "microchip,mcp3221", .data = (void *)mcp3221 },
+ { }
+};
+MODULE_DEVICE_TABLE(of, of_mcp3021_match);
+#endif
+
static struct i2c_driver mcp3021_driver = {
.driver = {
.name = "mcp3021",
+ .of_match_table = of_match_ptr(of_mcp3021_match),
},
.probe = mcp3021_probe,
.remove = mcp3021_remove,
--
2.10.2
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