On 10/27/2016 03:33 PM, Clemens Gruber wrote:
Support setting the reference voltage from 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.
Signed-off-by: Clemens Gruber <clemens.gru...@pqgruber.com>
---
Documentation/hwmon/mcp3021 | 6 ++
drivers/hwmon/mcp3021.c | 145 ++++++++++++++++++++++++++++++++------------
2 files changed, 111 insertions(+), 40 deletions(-)
diff --git a/Documentation/hwmon/mcp3021 b/Documentation/hwmon/mcp3021
index 74a6b72..be252b7 100644
--- a/Documentation/hwmon/mcp3021
+++ b/Documentation/hwmon/mcp3021
@@ -12,6 +12,7 @@ Supported chips:
Authors:
Mingkai Hu
Sven Schuchmann <schuchm...@schleissheimer.de>
+ Clemens Gruber <clemens.gru...@pqgruber.com>
Description
-----------
@@ -27,3 +28,8 @@ 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 through platform data
+in millivolt (for backwards compatibility) or via device tree in microvolt.
+Please refer to Documentation/devicetree/bindings/i2c/mcp3021.txt for details
+about the device tree bindings.
diff --git a/drivers/hwmon/mcp3021.c b/drivers/hwmon/mcp3021.c
index 972444a..a8cf97f 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...@freescale.com>
* Reworked by Sven Schuchmann <schuchm...@schleissheimer.de>
+ * Copyright (C) 2016 Clemens Gruber <clemens.gru...@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
@@ -22,37 +23,56 @@
#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
-
-/* output format */
-#define MCP3021_SAR_SHIFT 2
-#define MCP3021_SAR_MASK 0x3ff
-#define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */
-
-#define MCP3221_SAR_SHIFT 0
-#define MCP3221_SAR_MASK 0xfff
-#define MCP3221_OUTPUT_RES 12 /* 12-bit resolution */
+#define MCP3021_VDD_DEFAULT 3300
There is no technical reason to drop / change those defines and use literals
in the code instead. Please don't.
enum chips {
mcp3021,
mcp3221
};
+struct mcp3021_chip_info {
+ u16 sar_shift;
+ u16 sar_mask;
+ u8 output_res;
+};
+
/*
* 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;
+ const struct mcp3021_chip_info *chip_info;
+ u32 vdd; /* device power supply and reference voltage in millivolt */
};
+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 },
+ { }
+};
+MODULE_DEVICE_TABLE(of, of_mcp3021_match);
+#endif
+
static int mcp3021_read16(struct i2c_client *client)
{
struct mcp3021_data *data = i2c_get_clientdata(client);
@@ -73,14 +93,15 @@ 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,
@@ -101,44 +122,85 @@ static ssize_t show_in_input(struct device *dev, struct
device_attribute *attr,
static DEVICE_ATTR(in0_input, S_IRUGO, 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;
-
- i2c_set_clientdata(client, data);
+ devid = (int)(uintptr_t)match->data;
+ data->chip_info = &mcp3021_chip_info_tbl[devid];
- 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-microvolt",
+ &data->vdd);
+ if (ret) {
+ /* fallback */
+ data->vdd = MCP3021_VDD_DEFAULT;
+ return 0;
}
+ /* Convert microvolt from DT to millivolt used in the formula */
+ data->vdd /= 1000;
+
+ 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;
+
Most other drivers generate the platform data from devicetree data.
if (of_match_device())
pdata = probe_dt();
else
pdata = dev_get_platdata();
In this case, this is even simpler, since the only devicetree property is the
reference
voltage.
if (np) {
if (of_property_read_u32(np, "reference-voltage-microvolt",
&vdd))
vdd = MCP3021_VDD_REF * 1000;
vdd /= 1000;
devid = (int)(uintptr_t)match->data;
} else {
u32 *pdata = dev_get_platdata(&client->dev);
if (pdata)
vdd = *pdata;
else
vdd = MCP3021_VDD_REF;
devid = id->driver_data;
}
You should actually be able to use id->driver_data directly in both cases since
it is
always passed as parameter from the i2c core.
This would be much simpler than your suggested changes.
err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
if (err)
return err;
@@ -176,6 +238,9 @@ MODULE_DEVICE_TABLE(i2c, mcp3021_id);
static struct i2c_driver mcp3021_driver = {
.driver = {
.name = "mcp3021",
+#ifdef CONFIG_OF
+ .of_match_table = of_match_ptr(of_mcp3021_match),
+#endif
of_match_ptr() is already protected with #ifdef CONFIG_OF and otherwise
returns NULL, so this ifdef is unnecessary.
},
.probe = mcp3021_probe,
.remove = mcp3021_remove,
--
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