Support setting the reference voltage in the device tree.
Rework of driver structure, put chip specific data in a separate
structure and assign it depending on device id from platform data or
DT match.
Extend the device documentation and add new documentation for the
devicetree bindings.
Also change S_IRUGO to the better readable 0444, which fixes a
checkpatch warning.
Signed-off-by: Clemens Gruber <clemens.gruber@xxxxxxxxxxxx>
---
.../devicetree/bindings/hwmon/mcp3021.txt | 21 +++
Documentation/hwmon/mcp3021 | 5 +
drivers/hwmon/mcp3021.c | 184 ++++++++++++++-------
3 files changed, 149 insertions(+), 61 deletions(-)
create mode 100644 Documentation/devicetree/bindings/hwmon/mcp3021.txt
diff --git a/Documentation/devicetree/bindings/hwmon/mcp3021.txt b/Documentation/devicetree/bindings/hwmon/mcp3021.txt
new file mode 100644
index 0000000..e1d1e62
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/mcp3021.txt
@@ -0,0 +1,21 @@
+mcp3021 properties
+
+Required properties:
+- compatible: Must be one of the following:
+ - "microchip,mcp3021" for mcp3021
+ - "microchip,mcp3221" for mcp3221
+- reg: I2C address
+
+Optional properties:
+
+- reference-voltage
+ Reference voltage in millivolt (mV)
+
+Example:
+
+mcp3021@4d {
+ compatible = "microchip,mcp3021";
+ reg = <0x4d>;
+
+ reference-voltage = <4500>; /* 4.5 V */
+};
diff --git a/Documentation/hwmon/mcp3021 b/Documentation/hwmon/mcp3021
index 74a6b72..55792c3 100644
--- a/Documentation/hwmon/mcp3021
+++ b/Documentation/hwmon/mcp3021
@@ -12,6 +12,7 @@ Supported chips:
Authors:
Mingkai Hu
Sven Schuchmann <schuchmann@xxxxxxxxxxxxxxxxx>
+ Clemens Gruber <clemens.gruber@xxxxxxxxxxxx>
Description
-----------
@@ -27,3 +28,7 @@ Communication to the MCP3021/MCP3221 is performed using a 2-wire I2C
compatible interface. Standard (100 kHz) and Fast (400 kHz) I2C modes are
available. The default I2C device address is 0x4d (contact the Microchip
factory for additional address options).
+
+The reference-voltage used in the conversion can be set via platform data or
+device tree. Please refer to Documentation/devicetree/bindings/i2c/mcp3021.txt
+for information about the bindings if the device tree is used.
diff --git a/drivers/hwmon/mcp3021.c b/drivers/hwmon/mcp3021.c
index 972444a..ebbd3d2 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@xxxxxxxxxxxxx>
* Reworked by Sven Schuchmann <schuchmann@xxxxxxxxxxxxxxxxx>
+ * Copyright (C) 2016 Clemens Gruber <clemens.gruber@xxxxxxxxxxxx>
*
* This driver export the value of analog input voltage to sysfs, the
* voltage unit is mV. Through the sysfs interface, lm-sensors tool
@@ -22,35 +23,74 @@
#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 */
#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
-#define MCP3021_SAR_MASK 0x3ff
-#define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */
+struct mcp3021_chip_info {
+ u16 sar_shift;
+ u16 sar_mask;
+ u8 output_res;
+};
+
+struct mcp3021_data {
+ struct device *hwmon_dev;
+ const struct mcp3021_chip_info *chip_info;
+ u32 vdd; /* Supply and reference voltage for AD conversion */
+};
-#define MCP3221_SAR_SHIFT 0
-#define MCP3221_SAR_MASK 0xfff
-#define MCP3221_OUTPUT_RES 12 /* 12-bit resolution */
+static int mcp3021_probe(struct i2c_client *client,
+ const struct i2c_device_id *id);
+static int mcp3021_remove(struct i2c_client *client);
-enum chips {
+enum {
mcp3021,
mcp3221
};
-/*
- * Client data (each client gets its own)
- */
-struct mcp3021_data {
- struct device *hwmon_dev;
- u32 vdd; /* device power supply */
- u16 sar_shift;
- u16 sar_mask;
- u8 output_res;
+static const struct i2c_device_id mcp3021_id[] = {
+ { "mcp3021", mcp3021 },
+ { "mcp3221", mcp3221 },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, mcp3021_id);
+
+static const struct mcp3021_chip_info mcp3021_chip_info_tbl[] = {
+ [mcp3021] = {
+ .sar_shift = 2,
+ .sar_mask = 0x3ff,
+ .output_res = 10, /* 10-bit resolution */
+ },
+ [mcp3221] = {
+ .sar_shift = 0,
+ .sar_mask = 0xfff,
+ .output_res = 12, /* 12-bit resolution */
+ },
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_mcp3021_match[] = {
+ { .compatible = "microchip,mcp3021", .data = (void *)mcp3021 },
+ { .compatible = "microchip,mcp3221", .data = (void *)mcp3221 },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, of_mcp3021_match);
+#endif
+
+static struct i2c_driver mcp3021_driver = {
+ .driver = {
+ .name = "mcp3021",
+#ifdef CONFIG_OF
+ .of_match_table = of_match_ptr(of_mcp3021_match),
+#endif
+ },
+ .probe = mcp3021_probe,
+ .remove = mcp3021_remove,
+ .id_table = mcp3021_id,
};
static int mcp3021_read16(struct i2c_client *client)
@@ -73,14 +113,15 @@ static int mcp3021_read16(struct i2c_client *client)
* The ten-bit output code is composed of the lower 4-bit of the
* first byte and the upper 6-bit of the second byte.
*/
- reg = (reg >> data->sar_shift) & data->sar_mask;
+ reg = (reg >> data->chip_info->sar_shift) & data->chip_info->sar_mask;
return reg;
}
static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val)
{
- return DIV_ROUND_CLOSEST(data->vdd * val, 1 << data->output_res);
+ return DIV_ROUND_CLOSEST(data->vdd * val,
+ 1 << data->chip_info->output_res);
}
static ssize_t show_in_input(struct device *dev, struct device_attribute *attr,
@@ -99,46 +140,83 @@ static ssize_t show_in_input(struct device *dev, struct device_attribute *attr,
return sprintf(buf, "%d\n", in_input);
}
-static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL);
+static DEVICE_ATTR(in0_input, 0444, show_in_input, NULL);
-static int mcp3021_probe(struct i2c_client *client,
+#ifdef CONFIG_OF
+static int mcp3021_probe_dt(struct i2c_client *client,
const struct i2c_device_id *id)
{
- int err;
- struct mcp3021_data *data = NULL;
+ struct mcp3021_data *data = i2c_get_clientdata(client);
+ struct device_node *np = client->dev.of_node;
+ const struct of_device_id *match;
+ int devid, ret;
- if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ match = of_match_device(of_mcp3021_match, &client->dev);
+ if (!match)
return -ENODEV;
- data = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data),
- GFP_KERNEL);
- if (!data)
- return -ENOMEM;
+ devid = (int)(uintptr_t)match->data;
+ data->chip_info = &mcp3021_chip_info_tbl[devid];
- i2c_set_clientdata(client, data);
-
- switch (id->driver_data) {
- case mcp3021:
- data->sar_shift = MCP3021_SAR_SHIFT;
- data->sar_mask = MCP3021_SAR_MASK;
- data->output_res = MCP3021_OUTPUT_RES;
- break;
-
- case mcp3221:
- data->sar_shift = MCP3221_SAR_SHIFT;
- data->sar_mask = MCP3221_SAR_MASK;
- data->output_res = MCP3221_OUTPUT_RES;
- break;
+ ret = of_property_read_u32(np, "reference-voltage", &data->vdd);
+ if (ret) {
+ /* Fallback: Use default value */
+ data->vdd = MCP3021_VDD_DEFAULT;
+ return 0;
}
+ if (data->vdd > MCP3021_VDD_MAX || data->vdd < MCP3021_VDD_MIN)
+ return -EINVAL;
+
+ return 0;
+}
+#else
+static int mcp3021_probe_dt(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ return 1;
+}
+#endif
+
+static int mcp3021_probe_pdata(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct mcp3021_data *data = i2c_get_clientdata(client);
+
+ data->chip_info = &mcp3021_chip_info_tbl[id->driver_data];
+
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;
+ data->vdd = MCP3021_VDD_DEFAULT;
}
+ return 0;
+}
+
+static int mcp3021_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct mcp3021_data *data = NULL;
+ int err;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, data);
+
+ err = mcp3021_probe_dt(client, id);
+ if (err > 0)
+ mcp3021_probe_pdata(client, id);
+ else if (err < 0)
+ return err;
+
err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
if (err)
return err;
@@ -166,22 +244,6 @@ static int mcp3021_remove(struct i2c_client *client)
return 0;
}
-static const struct i2c_device_id mcp3021_id[] = {
- { "mcp3021", mcp3021 },
- { "mcp3221", mcp3221 },
- { }
-};
-MODULE_DEVICE_TABLE(i2c, mcp3021_id);
-
-static struct i2c_driver mcp3021_driver = {
- .driver = {
- .name = "mcp3021",
- },
- .probe = mcp3021_probe,
- .remove = mcp3021_remove,
- .id_table = mcp3021_id,
-};
-
module_i2c_driver(mcp3021_driver);
MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@xxxxxxxxxxxxx>");
--
2.10.0
--
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