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* [PATCH v2] *** Add Microchip MCP3422/3/4 high resolution ADC ***
@ 2013-08-14  9:04 Angelo Compagnucci
  2013-08-14  9:04 ` [PATCH] Add mcp3422 kernel driver Angelo Compagnucci
  0 siblings, 1 reply; 3+ messages in thread
From: Angelo Compagnucci @ 2013-08-14  9:04 UTC (permalink / raw)
  To: linux-iio; +Cc: Angelo Compagnucci

This patch add support for Microchip MCP3422/3/4 high resolution adc.

http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf

This review maintain the correct alphabetic order in Makefile and Kconfig and 
fixes some minor codestyle issues.
I' will be grateful to anyone who wants to review it.

Thank you!

Angelo Compagnucci (1):
  Add mcp3422 kernel driver

 drivers/iio/adc/Kconfig   |   10 ++
 drivers/iio/adc/Makefile  |    1 +
 drivers/iio/adc/mcp3422.c |  400 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 411 insertions(+)
 create mode 100644 drivers/iio/adc/mcp3422.c

-- 
1.7.9.5


^ permalink raw reply	[flat|nested] 3+ messages in thread
* [PATCH] Add mcp3422 kernel driver
  2013-08-14  9:04 [PATCH v2] *** Add Microchip MCP3422/3/4 high resolution ADC *** Angelo Compagnucci
@ 2013-08-14  9:04 ` Angelo Compagnucci
  2013-08-14  9:23   ` Peter Meerwald
  0 siblings, 1 reply; 3+ messages in thread
From: Angelo Compagnucci @ 2013-08-14  9:04 UTC (permalink / raw)
  To: linux-iio; +Cc: Angelo Compagnucci


Signed-off-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
---
 drivers/iio/adc/Kconfig   |   10 ++
 drivers/iio/adc/Makefile  |    1 +
 drivers/iio/adc/mcp3422.c |  400 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 411 insertions(+)
 create mode 100644 drivers/iio/adc/mcp3422.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 93129ec..372667c 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -143,6 +143,16 @@ config MCP320X
 	  This driver can also be built as a module. If so, the module will be
 	  called mcp320x.
 
+config MCP3422
+	tristate "Microchip Technology MCP3422/3/4 driver"
+	depends on I2C
+	help
+	  Say yes here to build support for Microchip Technology's MCP3422,
+	  MCP3423 or MCP3424 analog to digital converters.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called mcp3422.
+
 config TI_ADC081C
 	tristate "Texas Instruments ADC081C021/027"
 	depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 8f475d3..bae9f67 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
 obj-$(CONFIG_MAX1363) += max1363.o
 obj-$(CONFIG_MCP320X) += mcp320x.o
+obj-$(CONFIG_MCP3422) += mcp3422.o
 obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
 obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
 obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
diff --git a/drivers/iio/adc/mcp3422.c b/drivers/iio/adc/mcp3422.c
new file mode 100644
index 0000000..d45bbbe
--- /dev/null
+++ b/drivers/iio/adc/mcp3422.c
@@ -0,0 +1,400 @@
+/*
+ * mcp3422.c - driver for the Microchip mcp3422/3/4 chip family
+ *
+ * Copyright (C) 2013, Angelo Compagnucci
+ * Author: Angelo Compagnucci <angelo.compagnucci@gmail.com>
+ *
+ * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf
+ *
+ * This driver export the value of analog input voltage to sysfs, the
+ * voltage unit is nV.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/sysfs.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+/* Masks */
+#define MCP3422_CHANNEL_MASK	0x60
+#define MCP3422_PGA_MASK	0x03
+#define MCP3422_SRATE_MASK	0x0C
+#define MCP3422_SRATE_240	0x0
+#define MCP3422_SRATE_60	0x1
+#define MCP3422_SRATE_15	0x2
+#define MCP3422_SRATE_3	0x3
+
+#define MCP3422_CHANNEL(config)	(((config) & MCP3422_CHANNEL_MASK) >> 5)
+#define MCP3422_PGA(config)	((config) & MCP3422_PGA_MASK)
+#define MCP3422_SAMPLE_RATE(config)	(((config) & MCP3422_SRATE_MASK) >> 2)
+
+#define VREF 2048
+
+#define MCP3422_CHAN(index) \
+	{ \
+		.type = IIO_VOLTAGE, \
+		.indexed = 1, \
+		.channel = index, \
+		.address = index, \
+		.scan_index = index, \
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+	}
+
+/* LSB is in nV to eliminate floating point */
+static const u32 rates_to_lsb[] = {1000000, 250000, 62500, 15625};
+
+/*
+ * Client data (each client gets its own)
+ */
+struct mcp3422 {
+	struct i2c_client *i2c;
+	u8 config;
+};
+
+static int mcp3422_update_config(struct mcp3422 *adc)
+{
+	u8 buf[1];
+	buf[0] = adc->config;
+	return i2c_master_send(adc->i2c, buf, 1);
+}
+
+static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config)
+{
+	int ret = 0;
+	u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
+	u8 buf[4] = {'\0', '\0', '\0', '\0'};
+
+	*value = 0;
+
+	if (sample_rate == MCP3422_SRATE_3) {
+		ret = i2c_master_recv(adc->i2c, buf, 4);
+		*value += (s8)buf[0];
+		*value <<= 16;
+		*value |= buf[1] << 8;
+		*value |= buf[2];
+		*config = buf[3];
+		if (*value == 0xFFFFFFFF)
+			*value = 0;
+	} else {
+		ret = i2c_master_recv(adc->i2c, buf, 3);
+		*value += (s8)buf[0];
+		*value <<= 8;
+		*value |= buf[1];
+		*config = buf[2];
+	}
+
+	return ret;
+}
+
+static int mcp3422_read_channel(struct mcp3422 *adc,
+				struct iio_chan_spec const *channel, int *value)
+{
+	int ret, mtime = 0;
+	u8 current_config = 0;
+	u8 req_channel = channel->channel - 1;
+
+	ret = mcp3422_read(adc, value, &current_config);
+
+	if (req_channel != MCP3422_CHANNEL(current_config)) {
+		adc->config &= ~MCP3422_CHANNEL_MASK;
+		adc->config |= ((req_channel << 5) & MCP3422_CHANNEL_MASK);
+		mcp3422_update_config(adc);
+		switch (MCP3422_SAMPLE_RATE(current_config)) {
+		case MCP3422_SRATE_240:
+			mtime = 1000 / 240;
+			break;
+		case MCP3422_SRATE_60:
+			mtime = 1000 / 60;
+			break;
+		case MCP3422_SRATE_15:
+			mtime = 1000 / 15;
+			break;
+		case MCP3422_SRATE_3:
+			mtime = 1000 / 3;
+			break;
+		}
+		msleep(mtime);
+		ret = mcp3422_read(adc, value, &current_config);
+	}
+	return ret;
+}
+
+static int mcp3422_read_raw(struct iio_dev *iio,
+			    struct iio_chan_spec const *channel, int *value,
+			    int *shift, long mask)
+{
+	struct mcp3422 *adc = iio_priv(iio);
+	int err, temp = 0;
+
+	u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
+	u8 pga         = MCP3422_PGA(adc->config);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		err = mcp3422_read_channel(adc, channel, &temp);
+		if (err < 0)
+			return err;
+
+		/*
+		* Converting the output
+		*/
+		*value = (temp * rates_to_lsb[sample_rate])
+					/ (pga ? 1 << pga : 1);
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+
+		*value = VREF * 1000000;
+
+		return IIO_VAL_INT;
+
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t mcp3422_set_sample_rate(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct iio_dev *iio = i2c_get_clientdata(client);
+	struct mcp3422 *adc = iio_priv(iio);
+	u8 value = 0;
+
+	if (kstrtou8(buf, 10, &value) < 0)
+		return -EINVAL;
+
+	switch (value) {
+	case 240:
+		value = MCP3422_SRATE_240;
+		break;
+	case 60:
+		value = MCP3422_SRATE_60;
+		break;
+	case 15:
+		value = MCP3422_SRATE_15;
+		break;
+	case 3:
+		value = MCP3422_SRATE_3;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	adc->config &= ~MCP3422_SRATE_MASK;
+	adc->config |= ((value << 2) & MCP3422_SRATE_MASK);
+
+	mcp3422_update_config(adc);
+
+	return count;
+}
+
+static ssize_t mcp3422_get_sample_rate(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct iio_dev *iio = i2c_get_clientdata(client);
+	struct mcp3422 *adc = iio_priv(iio);
+	u8 value = 0;
+
+	switch (MCP3422_SAMPLE_RATE(adc->config)) {
+	case 0:
+		value = 240;
+		break;
+	case 1:
+		value = 60;
+		break;
+	case 2:
+		value = 15;
+		break;
+	case 3:
+		value = 3;
+		break;
+	}
+
+	return sprintf(buf, "%d\n", value);
+}
+
+static ssize_t mcp3422_set_pga(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct iio_dev *iio = i2c_get_clientdata(client);
+	struct mcp3422 *adc = iio_priv(iio);
+	u8 value = 0;
+
+	if (kstrtou8(buf, 10, &value) < 0)
+		return -EINVAL;
+
+	switch (value) {
+	case 1:
+		value = 0;
+		break;
+	case 2:
+		value = 1;
+		break;
+	case 4:
+		value = 2;
+		break;
+	case 8:
+		value = 3;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	adc->config &= ~MCP3422_PGA_MASK;
+	adc->config |= (value & MCP3422_PGA_MASK);
+
+	mcp3422_update_config(adc);
+
+	return count;
+}
+
+static ssize_t mcp3422_get_pga(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct iio_dev *iio = i2c_get_clientdata(client);
+	struct mcp3422 *adc = iio_priv(iio);
+
+	return sprintf(buf, "%d\n", 1 << MCP3422_PGA(adc->config));
+}
+
+static IIO_DEV_ATTR_SAMP_FREQ(S_IRUGO | S_IWUSR,
+			mcp3422_get_sample_rate,
+			mcp3422_set_sample_rate);
+static IIO_DEVICE_ATTR(pga,
+			S_IRUGO | S_IWUSR,
+			mcp3422_get_pga,
+			mcp3422_set_pga, 0);
+static IIO_CONST_ATTR(sampling_frequency_available, "240 60 15 3");
+static IIO_CONST_ATTR(pga_available, "1 2 4 8");
+
+static struct attribute *mcp3422_attributes[] = {
+	&iio_dev_attr_sampling_frequency.dev_attr.attr,
+	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
+	&iio_dev_attr_pga.dev_attr.attr,
+	&iio_const_attr_pga_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group mcp3422_attribute_group = {
+	.attrs = mcp3422_attributes,
+};
+
+static const struct iio_chan_spec mcp3422_channels[] = {
+	MCP3422_CHAN(1),
+	MCP3422_CHAN(2),
+	MCP3422_CHAN(3),
+	MCP3422_CHAN(4),
+};
+
+static const struct iio_info mcp3422_info = {
+	.read_raw = mcp3422_read_raw,
+	.attrs = &mcp3422_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static int mcp3422_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct iio_dev *iio;
+	struct mcp3422 *adc;
+	int err;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+		return -ENODEV;
+
+	iio = iio_device_alloc(sizeof(*adc));
+	if (!iio)
+		return -ENOMEM;
+
+	adc = iio_priv(iio);
+	adc->i2c = client;
+
+	/* meaningful default configuration */
+	adc->config = 0x10;
+
+	iio->dev.parent = &client->dev;
+	iio->name = dev_name(&client->dev);
+	iio->modes = INDIO_DIRECT_MODE;
+	iio->info = &mcp3422_info;
+
+	iio->channels = mcp3422_channels;
+	iio->num_channels = ARRAY_SIZE(mcp3422_channels);
+
+	err = iio_device_register(iio);
+	if (err < 0)
+		goto iio_free;
+
+	i2c_set_clientdata(client, iio);
+
+	mcp3422_update_config(adc);
+
+	return 0;
+
+iio_free:
+	iio_device_free(iio);
+
+	return err;
+}
+
+static int mcp3422_remove(struct i2c_client *client)
+{
+	struct iio_dev *iio = i2c_get_clientdata(client);
+
+	iio_device_unregister(iio);
+	iio_device_free(iio);
+
+	return 0;
+}
+
+static const struct i2c_device_id mcp3422_id[] = {
+	{ "mcp3422", 2 },
+	{ "mcp3423", 3 },
+	{ "mcp3424", 4 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mcp3422_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id mcp3422_of_match[] = {
+	{ .compatible = "mcp3422" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mcp3422_of_match);
+#endif
+
+static struct i2c_driver mcp3422_driver = {
+	.driver = {
+		.name = "mcp3422",
+		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(mcp3422_of_match),
+	},
+	.probe = mcp3422_probe,
+	.remove = mcp3422_remove,
+	.id_table = mcp3422_id,
+};
+module_i2c_driver(mcp3422_driver);
+
+MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
+MODULE_DESCRIPTION("Microchip mcp3422/3/4 driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.9.5


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] Add mcp3422 kernel driver
  2013-08-14  9:04 ` [PATCH] Add mcp3422 kernel driver Angelo Compagnucci
@ 2013-08-14  9:23   ` Peter Meerwald
  0 siblings, 0 replies; 3+ messages in thread
From: Peter Meerwald @ 2013-08-14  9:23 UTC (permalink / raw)
  To: Angelo Compagnucci; +Cc: linux-iio

>  drivers/iio/adc/Kconfig   |   10 ++
>  drivers/iio/adc/Makefile  |    1 +
>  drivers/iio/adc/mcp3422.c |  400 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 411 insertions(+)
>  create mode 100644 drivers/iio/adc/mcp3422.c

an I2C ADC, yeah, like!

comments inline

> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 93129ec..372667c 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -143,6 +143,16 @@ config MCP320X
>  	  This driver can also be built as a module. If so, the module will be
>  	  called mcp320x.
>  
> +config MCP3422
> +	tristate "Microchip Technology MCP3422/3/4 driver"
> +	depends on I2C
> +	help
> +	  Say yes here to build support for Microchip Technology's MCP3422,
> +	  MCP3423 or MCP3424 analog to digital converters.
> +
> +	  This driver can also be built as a module. If so, the module will be
> +	  called mcp3422.
> +
>  config TI_ADC081C
>  	tristate "Texas Instruments ADC081C021/027"
>  	depends on I2C
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 8f475d3..bae9f67 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
>  obj-$(CONFIG_MAX1363) += max1363.o
>  obj-$(CONFIG_MCP320X) += mcp320x.o
> +obj-$(CONFIG_MCP3422) += mcp3422.o
>  obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>  obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
>  obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
> diff --git a/drivers/iio/adc/mcp3422.c b/drivers/iio/adc/mcp3422.c
> new file mode 100644
> index 0000000..d45bbbe
> --- /dev/null
> +++ b/drivers/iio/adc/mcp3422.c
> @@ -0,0 +1,400 @@
> +/*
> + * mcp3422.c - driver for the Microchip mcp3422/3/4 chip family
> + *
> + * Copyright (C) 2013, Angelo Compagnucci
> + * Author: Angelo Compagnucci <angelo.compagnucci@gmail.com>
> + *
> + * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf
> + *
> + * This driver export the value of analog input voltage to sysfs, the

exports

> + * voltage unit is nV.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/delay.h>
> +#include <linux/sysfs.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +/* Masks */
> +#define MCP3422_CHANNEL_MASK	0x60
> +#define MCP3422_PGA_MASK	0x03
> +#define MCP3422_SRATE_MASK	0x0C
> +#define MCP3422_SRATE_240	0x0
> +#define MCP3422_SRATE_60	0x1
> +#define MCP3422_SRATE_15	0x2
> +#define MCP3422_SRATE_3	0x3
> +
> +#define MCP3422_CHANNEL(config)	(((config) & MCP3422_CHANNEL_MASK) >> 5)
> +#define MCP3422_PGA(config)	((config) & MCP3422_PGA_MASK)
> +#define MCP3422_SAMPLE_RATE(config)	(((config) & MCP3422_SRATE_MASK) >> 2)
> +
> +#define VREF 2048
> +
> +#define MCP3422_CHAN(index) \
> +	{ \
> +		.type = IIO_VOLTAGE, \
> +		.indexed = 1, \
> +		.channel = index, \
> +		.address = index, \

address is not used

> +		.scan_index = index, \

scan index is not used

> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> +	}
> +
> +/* LSB is in nV to eliminate floating point */
> +static const u32 rates_to_lsb[] = {1000000, 250000, 62500, 15625};
> +
> +/*
> + * Client data (each client gets its own)
> + */

single line comment

> +struct mcp3422 {
> +	struct i2c_client *i2c;
> +	u8 config;
> +};
> +
> +static int mcp3422_update_config(struct mcp3422 *adc)
> +{
> +	u8 buf[1];

maybe just 'u8 buf' ?

> +	buf[0] = adc->config;
> +	return i2c_master_send(adc->i2c, buf, 1);
> +}
> +
> +static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config)
> +{
> +	int ret = 0;
> +	u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
> +	u8 buf[4] = {'\0', '\0', '\0', '\0'};
> +
> +	*value = 0;
> +
> +	if (sample_rate == MCP3422_SRATE_3) {
> +		ret = i2c_master_recv(adc->i2c, buf, 4);
> +		*value += (s8)buf[0];
> +		*value <<= 16;
> +		*value |= buf[1] << 8;
> +		*value |= buf[2];
> +		*config = buf[3];
> +		if (*value == 0xFFFFFFFF)
> +			*value = 0;
> +	} else {
> +		ret = i2c_master_recv(adc->i2c, buf, 3);
> +		*value += (s8)buf[0];
> +		*value <<= 8;
> +		*value |= buf[1];
> +		*config = buf[2];
> +	}
> +
> +	return ret;
> +}
> +
> +static int mcp3422_read_channel(struct mcp3422 *adc,
> +				struct iio_chan_spec const *channel, int *value)
> +{
> +	int ret, mtime = 0;
> +	u8 current_config = 0;
> +	u8 req_channel = channel->channel - 1;
> +
> +	ret = mcp3422_read(adc, value, &current_config);

is it not possible to know beforehand that the current read is
for a different channel?

noone except the driver should control the device's configuration

locking seems necessary for the present strategy; the configuration could 
change in the meanwhile

> +
> +	if (req_channel != MCP3422_CHANNEL(current_config)) {
> +		adc->config &= ~MCP3422_CHANNEL_MASK;
> +		adc->config |= ((req_channel << 5) & MCP3422_CHANNEL_MASK);
> +		mcp3422_update_config(adc);
> +		switch (MCP3422_SAMPLE_RATE(current_config)) {
> +		case MCP3422_SRATE_240:
> +			mtime = 1000 / 240;
> +			break;
> +		case MCP3422_SRATE_60:
> +			mtime = 1000 / 60;
> +			break;
> +		case MCP3422_SRATE_15:
> +			mtime = 1000 / 15;
> +			break;
> +		case MCP3422_SRATE_3:
> +			mtime = 1000 / 3;
> +			break;
> +		}
> +		msleep(mtime);
> +		ret = mcp3422_read(adc, value, &current_config);
> +	}
> +	return ret;
> +}
> +
> +static int mcp3422_read_raw(struct iio_dev *iio,
> +			    struct iio_chan_spec const *channel, int *value,
> +			    int *shift, long mask)
> +{
> +	struct mcp3422 *adc = iio_priv(iio);
> +	int err, temp = 0;
> +
> +	u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
> +	u8 pga         = MCP3422_PGA(adc->config);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		err = mcp3422_read_channel(adc, channel, &temp);
> +		if (err < 0)
> +			return err;
> +
> +		/*
> +		* Converting the output
> +		*/

single line comment

> +		*value = (temp * rates_to_lsb[sample_rate])
> +					/ (pga ? 1 << pga : 1);
> +

scaling to be done in INFO_SCALE

> +		return IIO_VAL_INT;
> +
> +	case IIO_CHAN_INFO_SCALE:
> +
> +		*value = VREF * 1000000;
> +
> +		return IIO_VAL_INT;
> +
> +	default:
> +		break;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static ssize_t mcp3422_set_sample_rate(struct device *dev,
> +		struct device_attribute *attr,
> +		const char *buf, size_t count)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct iio_dev *iio = i2c_get_clientdata(client);
> +	struct mcp3422 *adc = iio_priv(iio);
> +	u8 value = 0;
> +
> +	if (kstrtou8(buf, 10, &value) < 0)
> +		return -EINVAL;
> +
> +	switch (value) {
> +	case 240:
> +		value = MCP3422_SRATE_240;
> +		break;
> +	case 60:
> +		value = MCP3422_SRATE_60;
> +		break;
> +	case 15:
> +		value = MCP3422_SRATE_15;
> +		break;
> +	case 3:
> +		value = MCP3422_SRATE_3;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	adc->config &= ~MCP3422_SRATE_MASK;
> +	adc->config |= ((value << 2) & MCP3422_SRATE_MASK);
> +
> +	mcp3422_update_config(adc);
> +
> +	return count;
> +}
> +
> +static ssize_t mcp3422_get_sample_rate(struct device *dev,
> +		struct device_attribute *attr,
> +		char *buf)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct iio_dev *iio = i2c_get_clientdata(client);
> +	struct mcp3422 *adc = iio_priv(iio);
> +	u8 value = 0;
> +
> +	switch (MCP3422_SAMPLE_RATE(adc->config)) {
> +	case 0:
> +		value = 240;
> +		break;
> +	case 1:
> +		value = 60;
> +		break;
> +	case 2:
> +		value = 15;
> +		break;
> +	case 3:
> +		value = 3;
> +		break;
> +	}
> +
> +	return sprintf(buf, "%d\n", value);
> +}
> +
> +static ssize_t mcp3422_set_pga(struct device *dev,
> +		struct device_attribute *attr,
> +		const char *buf, size_t count)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct iio_dev *iio = i2c_get_clientdata(client);
> +	struct mcp3422 *adc = iio_priv(iio);
> +	u8 value = 0;
> +
> +	if (kstrtou8(buf, 10, &value) < 0)
> +		return -EINVAL;
> +
> +	switch (value) {
> +	case 1:
> +		value = 0;
> +		break;
> +	case 2:
> +		value = 1;
> +		break;
> +	case 4:
> +		value = 2;
> +		break;
> +	case 8:
> +		value = 3;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	adc->config &= ~MCP3422_PGA_MASK;
> +	adc->config |= (value & MCP3422_PGA_MASK);
> +
> +	mcp3422_update_config(adc);
> +
> +	return count;
> +}
> +
> +static ssize_t mcp3422_get_pga(struct device *dev,
> +		struct device_attribute *attr,
> +		char *buf)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct iio_dev *iio = i2c_get_clientdata(client);
> +	struct mcp3422 *adc = iio_priv(iio);
> +
> +	return sprintf(buf, "%d\n", 1 << MCP3422_PGA(adc->config));
> +}
> +
> +static IIO_DEV_ATTR_SAMP_FREQ(S_IRUGO | S_IWUSR,
> +			mcp3422_get_sample_rate,
> +			mcp3422_set_sample_rate);
> +static IIO_DEVICE_ATTR(pga,
> +			S_IRUGO | S_IWUSR,
> +			mcp3422_get_pga,
> +			mcp3422_set_pga, 0);
> +static IIO_CONST_ATTR(sampling_frequency_available, "240 60 15 3");
> +static IIO_CONST_ATTR(pga_available, "1 2 4 8");
> +
> +static struct attribute *mcp3422_attributes[] = {
> +	&iio_dev_attr_sampling_frequency.dev_attr.attr,
> +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
> +	&iio_dev_attr_pga.dev_attr.attr,
> +	&iio_const_attr_pga_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group mcp3422_attribute_group = {
> +	.attrs = mcp3422_attributes,
> +};
> +
> +static const struct iio_chan_spec mcp3422_channels[] = {
> +	MCP3422_CHAN(1),
> +	MCP3422_CHAN(2),
> +	MCP3422_CHAN(3),
> +	MCP3422_CHAN(4),
> +};
> +
> +static const struct iio_info mcp3422_info = {
> +	.read_raw = mcp3422_read_raw,
> +	.attrs = &mcp3422_attribute_group,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +static int mcp3422_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct iio_dev *iio;
> +	struct mcp3422 *adc;
> +	int err;
> +
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
> +		return -ENODEV;

driver does not use WORD transfers

> +
> +	iio = iio_device_alloc(sizeof(*adc));
> +	if (!iio)
> +		return -ENOMEM;

devm_iio_device_alloc()

> +
> +	adc = iio_priv(iio);
> +	adc->i2c = client;
> +
> +	/* meaningful default configuration */
> +	adc->config = 0x10;

0x10 could/should be replaced by meaningful constants like SRATE_XX, PGA, 
etc.

> +
> +	iio->dev.parent = &client->dev;
> +	iio->name = dev_name(&client->dev);
> +	iio->modes = INDIO_DIRECT_MODE;
> +	iio->info = &mcp3422_info;
> +
> +	iio->channels = mcp3422_channels;
> +	iio->num_channels = ARRAY_SIZE(mcp3422_channels);
> +
> +	err = iio_device_register(iio);
> +	if (err < 0)
> +		goto iio_free;
> +
> +	i2c_set_clientdata(client, iio);
> +
> +	mcp3422_update_config(adc);
> +
> +	return 0;
> +
> +iio_free:
> +	iio_device_free(iio);
> +
> +	return err;
> +}
> +
> +static int mcp3422_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *iio = i2c_get_clientdata(client);
> +
> +	iio_device_unregister(iio);
> +	iio_device_free(iio);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id mcp3422_id[] = {
> +	{ "mcp3422", 2 },
> +	{ "mcp3423", 3 },
> +	{ "mcp3424", 4 },
> +	{ }
> +};

what is the difference between the devices? 
id doesn't get used?

> +MODULE_DEVICE_TABLE(i2c, mcp3422_id);
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id mcp3422_of_match[] = {
> +	{ .compatible = "mcp3422" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, mcp3422_of_match);
> +#endif
> +
> +static struct i2c_driver mcp3422_driver = {
> +	.driver = {
> +		.name = "mcp3422",
> +		.owner = THIS_MODULE,
> +		.of_match_table = of_match_ptr(mcp3422_of_match),
> +	},
> +	.probe = mcp3422_probe,
> +	.remove = mcp3422_remove,
> +	.id_table = mcp3422_id,
> +};
> +module_i2c_driver(mcp3422_driver);
> +
> +MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
> +MODULE_DESCRIPTION("Microchip mcp3422/3/4 driver");
> +MODULE_LICENSE("GPL v2");
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-08-14  9:23 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-08-14  9:04 [PATCH v2] *** Add Microchip MCP3422/3/4 high resolution ADC *** Angelo Compagnucci
2013-08-14  9:04 ` [PATCH] Add mcp3422 kernel driver Angelo Compagnucci
2013-08-14  9:23   ` Peter Meerwald

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