Merge tag 'iio-for-3.10c' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes: Third round of IIO cleanups, graduations and new stuff for the 3.10 cycle. A small set including 3 things. 1) A short cleanup series for the ak8975. 2) Graduation of ak8975 out of staging. 3) Some additional bits for the at91 adc driver to cover low resolution modes, sleep and a little bit of missing documentation.
2026-05-14 17:06:24 -04:00 · 2013-04-02 12:37:02 -07:00
parent 03b7f67bd1 beca9e767e
commit 6d3a63790c
7 changed files with 127 additions and 69 deletions
--- a/Documentation/devicetree/bindings/arm/atmel-adc.txt
+++ b/Documentation/devicetree/bindings/arm/atmel-adc.txt
@@ -14,9 +14,19 @@ Required properties:
  - atmel,adc-status-register: Offset of the Interrupt Status Register
  - atmel,adc-trigger-register: Offset of the Trigger Register
  - atmel,adc-vref: Reference voltage in millivolts for the conversions
+  - atmel,adc-res: List of resolution in bits supported by the ADC. List size
+		   must be two at least.
+  - atmel,adc-res-names: Contains one identifier string for each resolution
+			 in atmel,adc-res property. "lowres" and "highres"
+			 identifiers are required.

 Optional properties:
  - atmel,adc-use-external: Boolean to enable of external triggers
+  - atmel,adc-use-res: String corresponding to an identifier from
+		       atmel,adc-res-names property. If not specified, the highest
+		       resolution will be used.
+  - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
+  - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
 
 Optional trigger Nodes:
  - Required properties:
@@ -40,6 +50,9 @@ adc0: adc@fffb0000 {
 	atmel,adc-trigger-register = <0x08>;
 	atmel,adc-use-external;
 	atmel,adc-vref = <3300>;
+	atmel,adc-res = <8 10>;
+	atmel,adc-res-names = "lowres", "highres";
+	atmel,adc-use-res = "lowres";

 	trigger@0 {
 		trigger-name = "external-rising";
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -52,11 +52,15 @@ struct at91_adc_state {
 	void __iomem		*reg_base;
 	struct at91_adc_reg_desc *registers;
 	u8			startup_time;
+	u8			sample_hold_time;
+	bool			sleep_mode;
 	struct iio_trigger	**trig;
 	struct at91_adc_trigger	*trigger_list;
 	u32			trigger_number;
 	bool			use_external;
 	u32			vref_mv;
+	u32			res;		/* resolution used for convertions */
+	bool			low_res;	/* the resolution corresponds to the lowest one */
 	wait_queue_head_t	wq_data_avail;
 };

@@ -138,7 +142,7 @@ static int at91_adc_channel_init(struct iio_dev *idev)
 		chan->channel = bit;
 		chan->scan_index = idx;
 		chan->scan_type.sign = 'u';
-		chan->scan_type.realbits = 10;
+		chan->scan_type.realbits = st->res;
 		chan->scan_type.storagebits = 16;
 		chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
 		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
@@ -372,6 +376,59 @@ static int at91_adc_read_raw(struct iio_dev *idev,
 	return -EINVAL;
 }

+static int at91_adc_of_get_resolution(struct at91_adc_state *st,
+				      struct platform_device *pdev)
+{
+	struct iio_dev *idev = iio_priv_to_dev(st);
+	struct device_node *np = pdev->dev.of_node;
+	int count, i, ret = 0;
+	char *res_name, *s;
+	u32 *resolutions;
+
+	count = of_property_count_strings(np, "atmel,adc-res-names");
+	if (count < 2) {
+		dev_err(&idev->dev, "You must specified at least two resolution names for "
+				    "adc-res-names property in the DT\n");
+		return count;
+	}
+
+	resolutions = kmalloc(count * sizeof(*resolutions), GFP_KERNEL);
+	if (!resolutions)
+		return -ENOMEM;
+
+	if (of_property_read_u32_array(np, "atmel,adc-res", resolutions, count)) {
+		dev_err(&idev->dev, "Missing adc-res property in the DT.\n");
+		ret = -ENODEV;
+		goto ret;
+	}
+
+	if (of_property_read_string(np, "atmel,adc-use-res", (const char **)&res_name))
+		res_name = "highres";
+
+	for (i = 0; i < count; i++) {
+		if (of_property_read_string_index(np, "atmel,adc-res-names", i, (const char **)&s))
+			continue;
+
+		if (strcmp(res_name, s))
+			continue;
+
+		st->res = resolutions[i];
+		if (!strcmp(res_name, "lowres"))
+			st->low_res = true;
+		else
+			st->low_res = false;
+
+		dev_info(&idev->dev, "Resolution used: %u bits\n", st->res);
+		goto ret;
+	}
+
+	dev_err(&idev->dev, "There is no resolution for %s\n", res_name);
+
+ret:
+	kfree(resolutions);
+	return ret;
+}
+
 static int at91_adc_probe_dt(struct at91_adc_state *st,
 			     struct platform_device *pdev)
 {
@@ -400,6 +457,8 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
 	}
 	st->num_channels = prop;

+	st->sleep_mode = of_property_read_bool(node, "atmel,adc-sleep-mode");
+
 	if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) {
 		dev_err(&idev->dev, "Missing adc-startup-time property in the DT.\n");
 		ret = -EINVAL;
@@ -407,6 +466,9 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
 	}
 	st->startup_time = prop;

+	prop = 0;
+	of_property_read_u32(node, "atmel,adc-sample-hold-time", &prop);
+	st->sample_hold_time = prop;

 	if (of_property_read_u32(node, "atmel,adc-vref", &prop)) {
 		dev_err(&idev->dev, "Missing adc-vref property in the DT.\n");
@@ -415,6 +477,10 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
 	}
 	st->vref_mv = prop;

+	ret = at91_adc_of_get_resolution(st, pdev);
+	if (ret)
+		goto error_ret;
+
 	st->registers = devm_kzalloc(&idev->dev,
 				     sizeof(struct at91_adc_reg_desc),
 				     GFP_KERNEL);
@@ -516,11 +582,12 @@ static const struct iio_info at91_adc_info = {

 static int at91_adc_probe(struct platform_device *pdev)
 {
-	unsigned int prsc, mstrclk, ticks, adc_clk;
+	unsigned int prsc, mstrclk, ticks, adc_clk, shtim;
 	int ret;
 	struct iio_dev *idev;
 	struct at91_adc_state *st;
 	struct resource *res;
+	u32 reg;

 	idev = iio_device_alloc(sizeof(struct at91_adc_state));
 	if (idev == NULL) {
@@ -628,9 +695,22 @@ static int at91_adc_probe(struct platform_device *pdev)
 	 */
 	ticks = round_up((st->startup_time * adc_clk /
 			  1000000) - 1, 8) / 8;
-	at91_adc_writel(st, AT91_ADC_MR,
-			(AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL) |
-			(AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP));
+	/*
+	 * a minimal Sample and Hold Time is necessary for the ADC to guarantee
+	 * the best converted final value between two channels selection
+	 * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
+	 */
+	shtim = round_up((st->sample_hold_time * adc_clk /
+			  1000000) - 1, 1);
+
+	reg = AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL;
+	reg |= AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP;
+	if (st->low_res)
+		reg |= AT91_ADC_LOWRES;
+	if (st->sleep_mode)
+		reg |= AT91_ADC_SLEEP;
+	reg |= AT91_ADC_SHTIM_(shtim) & AT91_ADC_SHTIM;
+	at91_adc_writel(st, AT91_ADC_MR, reg);

 	/* Setup the ADC channels available on the board */
 	ret = at91_adc_channel_init(idev);
--- a/drivers/iio/magnetometer/Kconfig
+++ b/drivers/iio/magnetometer/Kconfig
@@ -3,6 +3,17 @@
 #
 menu "Magnetometer sensors"

+config AK8975
+	tristate "Asahi Kasei AK8975 3-Axis Magnetometer"
+	depends on I2C
+	depends on GPIOLIB
+	help
+	  Say yes here to build support for Asahi Kasei AK8975 3-Axis
+	  Magnetometer.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called ak8975.
+
 config HID_SENSOR_MAGNETOMETER_3D
 	depends on HID_SENSOR_HUB
 	select IIO_BUFFER
--- a/drivers/iio/magnetometer/Makefile
+++ b/drivers/iio/magnetometer/Makefile
@@ -2,6 +2,7 @@
 # Makefile for industrial I/O Magnetometer sensor drivers
 #

+obj-$(CONFIG_AK8975)	+= ak8975.o
 obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o

 obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o
--- a/drivers/staging/iio/magnetometer/ak8975.c
+++ b/drivers/staging/iio/magnetometer/ak8975.c
@@ -94,7 +94,6 @@ struct ak8975_data {
 	long			raw_to_gauss[3];
 	u8			reg_cache[AK8975_MAX_REGS];
 	int			eoc_gpio;
-	int			eoc_irq;
 };

 static const int ak8975_index_to_reg[] = {
@@ -123,36 +122,6 @@ static int ak8975_write_data(struct i2c_client *client,
 	return 0;
 }

-/*
- * Helper function to read a contiguous set of the I2C device's registers.
- */
-static int ak8975_read_data(struct i2c_client *client,
-			    u8 reg, u8 length, u8 *buffer)
-{
-	int ret;
-	struct i2c_msg msg[2] = {
-		{
-			.addr = client->addr,
-			.flags = I2C_M_NOSTART,
-			.len = 1,
-			.buf = &reg,
-		}, {
-			.addr = client->addr,
-			.flags = I2C_M_RD,
-			.len = length,
-			.buf = buffer,
-		}
-	};
-
-	ret = i2c_transfer(client->adapter, msg, 2);
-	if (ret < 0) {
-		dev_err(&client->dev, "Read from device fails\n");
-		return ret;
-	}
-
-	return 0;
-}
-
 /*
 * Perform some start-of-day setup, including reading the asa calibration
 * values and caching them.
@@ -165,11 +134,12 @@ static int ak8975_setup(struct i2c_client *client)
 	int ret;

 	/* Confirm that the device we're talking to is really an AK8975. */
-	ret = ak8975_read_data(client, AK8975_REG_WIA, 1, &device_id);
+	ret = i2c_smbus_read_byte_data(client, AK8975_REG_WIA);
 	if (ret < 0) {
 		dev_err(&client->dev, "Error reading WIA\n");
 		return ret;
 	}
+	device_id = ret;
 	if (device_id != AK8975_DEVICE_ID) {
 		dev_err(&client->dev, "Device ak8975 not found\n");
 		return -ENODEV;
@@ -187,7 +157,8 @@ static int ak8975_setup(struct i2c_client *client)
 	}

 	/* Get asa data and store in the device data. */
-	ret = ak8975_read_data(client, AK8975_REG_ASAX, 3, data->asa);
+	ret = i2c_smbus_read_i2c_block_data(client, AK8975_REG_ASAX,
+					    3, data->asa);
 	if (ret < 0) {
 		dev_err(&client->dev, "Not able to read asa data\n");
 		return ret;
@@ -249,7 +220,6 @@ static int ak8975_setup(struct i2c_client *client)
 static int wait_conversion_complete_gpio(struct ak8975_data *data)
 {
 	struct i2c_client *client = data->client;
-	u8 read_status;
 	u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
 	int ret;

@@ -265,12 +235,11 @@ static int wait_conversion_complete_gpio(struct ak8975_data *data)
 		return -EINVAL;
 	}

-	ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status);
-	if (ret < 0) {
+	ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1);
+	if (ret < 0)
 		dev_err(&client->dev, "Error in reading ST1\n");
-		return ret;
-	}
-	return read_status;
+
+	return ret;
 }

 static int wait_conversion_complete_polled(struct ak8975_data *data)
@@ -283,11 +252,12 @@ static int wait_conversion_complete_polled(struct ak8975_data *data)
 	/* Wait for the conversion to complete. */
 	while (timeout_ms) {
 		msleep(AK8975_CONVERSION_DONE_POLL_TIME);
-		ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status);
+		ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1);
 		if (ret < 0) {
 			dev_err(&client->dev, "Error in reading ST1\n");
 			return ret;
 		}
+		read_status = ret;
 		if (read_status)
 			break;
 		timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
@@ -308,7 +278,6 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
 	struct i2c_client *client = data->client;
 	u16 meas_reg;
 	s16 raw;
-	u8 read_status;
 	int ret;

 	mutex_lock(&data->lock);
@@ -332,18 +301,15 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
 	if (ret < 0)
 		goto exit;

-	read_status = ret;
-
-	if (read_status & AK8975_REG_ST1_DRDY_MASK) {
-		ret = ak8975_read_data(client, AK8975_REG_ST2, 1, &read_status);
+	if (ret & AK8975_REG_ST1_DRDY_MASK) {
+		ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST2);
 		if (ret < 0) {
 			dev_err(&client->dev, "Error in reading ST2\n");
 			goto exit;
 		}
-		if (read_status & (AK8975_REG_ST2_DERR_MASK |
-				   AK8975_REG_ST2_HOFL_MASK)) {
-			dev_err(&client->dev, "ST2 status error 0x%x\n",
-				read_status);
+		if (ret & (AK8975_REG_ST2_DERR_MASK |
+			   AK8975_REG_ST2_HOFL_MASK)) {
+			dev_err(&client->dev, "ST2 status error 0x%x\n", ret);
 			ret = -EINVAL;
 			goto exit;
 		}
@@ -351,12 +317,12 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)

 	/* Read the flux value from the appropriate register
 	   (the register is specified in the iio device attributes). */
-	ret = ak8975_read_data(client, ak8975_index_to_reg[index],
-			       2, (u8 *)&meas_reg);
+	ret = i2c_smbus_read_word_data(client, ak8975_index_to_reg[index]);
 	if (ret < 0) {
 		dev_err(&client->dev, "Read axis data fails\n");
 		goto exit;
 	}
+	meas_reg = ret;

 	mutex_unlock(&data->lock);

@@ -452,7 +418,6 @@ static int ak8975_probe(struct i2c_client *client,

 	data->client = client;
 	mutex_init(&data->lock);
-	data->eoc_irq = client->irq;
 	data->eoc_gpio = eoc_gpio;
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->channels = ak8975_channels;
--- a/drivers/staging/iio/magnetometer/Kconfig
+++ b/drivers/staging/iio/magnetometer/Kconfig
@@ -3,17 +3,6 @@
 #
 menu "Magnetometer sensors"

-config SENSORS_AK8975
-	tristate "Asahi Kasei AK8975 3-Axis Magnetometer"
-	depends on I2C
-	depends on GPIOLIB
-	help
-	  Say yes here to build support for Asahi Kasei AK8975 3-Axis
-	  Magnetometer.
-
-	  To compile this driver as a module, choose M here: the module
-	  will be called ak8975.
-
 config SENSORS_HMC5843
 	tristate "Honeywell HMC5843/5883/5883L 3-Axis Magnetometer"
 	depends on I2C
--- a/drivers/staging/iio/magnetometer/Makefile
+++ b/drivers/staging/iio/magnetometer/Makefile
@@ -2,5 +2,4 @@
 # Makefile for industrial I/O Magnetometer sensors
 #

-obj-$(CONFIG_SENSORS_AK8975)	+= ak8975.o
 obj-$(CONFIG_SENSORS_HMC5843)	+= hmc5843.o