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 <[email protected]>
---
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 <[email protected]>
+ Clemens Gruber <[email protected]>
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 <[email protected]>
* Reworked by Sven Schuchmann <[email protected]>
+ * Copyright (C) 2016 Clemens Gruber <[email protected]>
*
* 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
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;
+
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
},
.probe = mcp3021_probe,
.remove = mcp3021_remove,
--
2.10.1
Replace S_IRUGO with the better readable 0444.
This fixes a checkpatch warning.
Signed-off-by: Clemens Gruber <[email protected]>
---
drivers/hwmon/mcp3021.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hwmon/mcp3021.c b/drivers/hwmon/mcp3021.c
index a8cf97f..97c832d 100644
--- a/drivers/hwmon/mcp3021.c
+++ b/drivers/hwmon/mcp3021.c
@@ -120,7 +120,7 @@ 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);
#ifdef CONFIG_OF
static int mcp3021_probe_dt(struct i2c_client *client,
--
2.10.1
Document the devicetree bindings for the Microchip MCP3021/3221.
Signed-off-by: Clemens Gruber <[email protected]>
---
Documentation/devicetree/bindings/hwmon/mcp3021.txt | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
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..294318b
--- /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-microvolt
+ Reference voltage in microvolt (uV)
+
+Example:
+
+mcp3021@4d {
+ compatible = "microchip,mcp3021";
+ reg = <0x4d>;
+
+ reference-voltage-microvolt = <4500000>; /* 4.5 V */
+};
--
2.10.1
On Fri, Oct 28, 2016 at 12:33:44AM +0200, Clemens Gruber wrote:
> Document the devicetree bindings for the Microchip MCP3021/3221.
>
> Signed-off-by: Clemens Gruber <[email protected]>
> ---
> Documentation/devicetree/bindings/hwmon/mcp3021.txt | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/hwmon/mcp3021.txt
Acked-by: Rob Herring <[email protected]>
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 <[email protected]>
> ---
> 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 <[email protected]>
> + Clemens Gruber <[email protected]>
>
> 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 <[email protected]>
> * Reworked by Sven Schuchmann <[email protected]>
> + * Copyright (C) 2016 Clemens Gruber <[email protected]>
> *
> * 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,
>
On Fri, Oct 28, 2016 at 12:33:44AM +0200, Clemens Gruber wrote:
> Document the devicetree bindings for the Microchip MCP3021/3221.
>
> Signed-off-by: Clemens Gruber <[email protected]>
> Acked-by: Rob Herring <[email protected]>
Applied to -next.
Guenter