[PATCH v5 0/5] HID: mcp2221: iio support and device resource management

[PATCH v5 0/5] HID: mcp2221: iio support and device resource management

[Matt Ranostay]

This patchset is primarily to enable iio support for the MCP2221 HID driver,
but requires several Kconfig changes and device resource management.

First attempt of this patchset is referenced here:

Link: https://lore.kernel.org/all/20220729154723.99947-1-matt.ranostay@xxxxxxxxxxxx/

Changes from v1:
* Fixing various Kconfig recursive dependencies that appear with 'imply IIO'
* Switch hid-mcp2221 driver to device managed resources for i2c support
* Reworking patchset per advice on lore.kernel.org link above

Changes from v2:
* add linux-iio list to CC

Changes from v3:
* replace .remove() tasks with devm_add_action_or_reset() in .probe()
* reschedule SRAM configuration read on failures
* add IIO_CHAN_INFO_SCALE values for ADC + DAC based on reference voltage

Changes from v4:
* add .remove function with no operation to avoid hid_hw_stop() being called
  twice due to new devm functions
* add retries limit to five for reading SRAM configuration data
* update 'io: adc: stx104: fix future recursive dependencies' to new Kconfig
  location for STX104 driver on linux-next pending-fixes branch

Matt Ranostay (5):
  i2c: muxes: ltc4306: fix future recursive dependencies
  iio: adc: stx104: fix future recursive dependencies
  iio: dac: fix future recursive dependencies
  HID: mcp2221: switch i2c registration to devm functions
  HID: mcp2221: add ADC/DAC support via iio subsystem

 drivers/hid/Kconfig       |   1 +
 drivers/hid/hid-mcp2221.c | 309 ++++++++++++++++++++++++++++++++++----
 drivers/i2c/muxes/Kconfig |   2 +-
 drivers/iio/adc/Kconfig   |   3 +-
 drivers/iio/dac/Kconfig   |   6 +-
 5 files changed, 288 insertions(+), 33 deletions(-)

-- 
2.37.2

[PATCH v5 1/5] i2c: muxes: ltc4306: fix future recursive dependencies

[Matt Ranostay]

When using 'imply IIO' for other configurations which have 'select GPIOLIB'
the following recursive dependency is detected for I2C_MUX_LTC4306

Switch from 'select GPIOLIB' to 'depends on GPIOLIB' to avoid this per
recommendation in kconfig-language.rst

drivers/gpio/Kconfig:14:error: recursive dependency detected!
drivers/gpio/Kconfig:14:        symbol GPIOLIB is selected by I2C_MUX_LTC4306
drivers/i2c/muxes/Kconfig:47:   symbol I2C_MUX_LTC4306 depends on I2C_MUX
drivers/i2c/Kconfig:62: symbol I2C_MUX is selected by MPU3050_I2C
drivers/iio/gyro/Kconfig:127:   symbol MPU3050_I2C depends on IIO
drivers/iio/Kconfig:6:  symbol IIO is implied by HID_MCP2221
drivers/hid/Kconfig:1227:       symbol HID_MCP2221 depends on GPIOLIB

Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
---
 drivers/i2c/muxes/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index 1708b1a82da2..8642ea8e0a3d 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -46,7 +46,7 @@ config I2C_MUX_GPMUX
 
 config I2C_MUX_LTC4306
 	tristate "LTC LTC4306/5 I2C multiplexer"
-	select GPIOLIB
+	depends on GPIOLIB
 	select REGMAP_I2C
 	help
 	  If you say yes here you get support for the Analog Devices
-- 
2.37.2

[PATCH v5 2/5] iio: adc: stx104: fix future recursive dependencies

[Matt Ranostay]

When using 'imply IIO' for other configurations which have 'select GPIOLIB'
the following recursive dependency is detected for STX1040

Switch from 'select GPIOLIB' to 'depends on GPIOLIB' to avoid this per
recommendation in kconfig-language.rst

drivers/gpio/Kconfig:14:error: recursive dependency detected!
drivers/gpio/Kconfig:14:        symbol GPIOLIB is selected by STX104
drivers/iio/adc/Kconfig:20:   symbol STX104 depends on IIO
drivers/iio/Kconfig:6:  symbol IIO is implied by HID_MCP2221
drivers/hid/Kconfig:1227:       symbol HID_MCP2221 depends on GPIOLIB

Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
---
 drivers/iio/adc/Kconfig | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 7fe5930891e0..929dd9493479 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1024,9 +1024,8 @@ config STMPE_ADC
 
 config STX104
 	tristate "Apex Embedded Systems STX104 driver"
-	depends on PC104 && X86
+	depends on PC104 && X86 && GPIOLIB
 	select ISA_BUS_API
-	select GPIOLIB
 	help
 	  Say yes here to build support for the Apex Embedded Systems STX104
 	  integrated analog PC/104 card.
-- 
2.37.2

[PATCH v5 3/5] iio: dac: fix future recursive dependencies

[Matt Ranostay]

When using 'imply IIO' for other configurations which have 'select GPIOLIB'
the following recursive dependency is detected for AD5592R/AD5593R

Switch from 'select GPIOLIB' to 'depends on GPIOLIB' to avoid this per
recommendation in kconfig-language.rst

drivers/gpio/Kconfig:14:error: recursive dependency detected!
drivers/gpio/Kconfig:14:        symbol GPIOLIB is selected by AD5592R
drivers/iio/dac/Kconfig:93:     symbol AD5592R depends on IIO
drivers/iio/Kconfig:6:  symbol IIO is implied by HID_MCP2221
drivers/hid/Kconfig:1227:       symbol HID_MCP2221 depends on GPIOLIB

Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
---
 drivers/iio/dac/Kconfig | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index 80521bd28d0f..b93003e80b70 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -92,8 +92,7 @@ config AD5592R_BASE
 
 config AD5592R
 	tristate "Analog Devices AD5592R ADC/DAC driver"
-	depends on SPI_MASTER
-	select GPIOLIB
+	depends on SPI_MASTER && GPIOLIB
 	select AD5592R_BASE
 	help
 	  Say yes here to build support for Analog Devices AD5592R
@@ -104,8 +103,7 @@ config AD5592R
 
 config AD5593R
 	tristate "Analog Devices AD5593R ADC/DAC driver"
-	depends on I2C
-	select GPIOLIB
+	depends on I2C && GPIOLIB
 	select AD5592R_BASE
 	help
 	  Say yes here to build support for Analog Devices AD5593R
-- 
2.37.2

[PATCH v5 4/5] HID: mcp2221: switch i2c registration to devm functions

[Matt Ranostay]

Switch from i2c_add_adapter() to resource managed devm_i2c_add_adapter()
for matching rest of driver initialization, and more concise code.

Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
---
 drivers/hid/hid-mcp2221.c | 51 ++++++++++++++++++++-------------------
 1 file changed, 26 insertions(+), 25 deletions(-)

diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c
index de52e9f7bb8c..3365e21547c6 100644
--- a/drivers/hid/hid-mcp2221.c
+++ b/drivers/hid/hid-mcp2221.c
@@ -824,6 +824,21 @@ static int mcp2221_raw_event(struct hid_device *hdev,
 	return 1;
 }
 
+/* Device resource managed function for HID unregistration */
+static void mcp2221_hid_unregister(void *ptr)
+{
+	struct hid_device *hdev = ptr;
+
+	hid_hw_close(hdev);
+	hid_hw_stop(hdev);
+}
+
+/* This is needed to be sure hid_hw_stop() isn't called twice by the subsystem */
+static void mcp2221_remove(struct hid_device *hdev)
+{
+	return;
+}
+
 static int mcp2221_probe(struct hid_device *hdev,
 					const struct hid_device_id *id)
 {
@@ -849,7 +864,8 @@ static int mcp2221_probe(struct hid_device *hdev,
 	ret = hid_hw_open(hdev);
 	if (ret) {
 		hid_err(hdev, "can't open device\n");
-		goto err_hstop;
+		hid_hw_stop(hdev);
+		return ret;
 	}
 
 	mutex_init(&mcp->lock);
@@ -857,6 +873,10 @@ static int mcp2221_probe(struct hid_device *hdev,
 	hid_set_drvdata(hdev, mcp);
 	mcp->hdev = hdev;
 
+	ret = devm_add_action_or_reset(&hdev->dev, mcp2221_hid_unregister, hdev);
+	if (ret)
+		return ret;
+
 	/* Set I2C bus clock diviser */
 	if (i2c_clk_freq > 400)
 		i2c_clk_freq = 400;
@@ -873,19 +893,17 @@ static int mcp2221_probe(struct hid_device *hdev,
 			"MCP2221 usb-i2c bridge on hidraw%d",
 			((struct hidraw *)hdev->hidraw)->minor);
 
-	ret = i2c_add_adapter(&mcp->adapter);
+	ret = devm_i2c_add_adapter(&hdev->dev, &mcp->adapter);
 	if (ret) {
 		hid_err(hdev, "can't add usb-i2c adapter: %d\n", ret);
-		goto err_i2c;
+		return ret;
 	}
 	i2c_set_adapdata(&mcp->adapter, mcp);
 
 	/* Setup GPIO chip */
 	mcp->gc = devm_kzalloc(&hdev->dev, sizeof(*mcp->gc), GFP_KERNEL);
-	if (!mcp->gc) {
-		ret = -ENOMEM;
-		goto err_gc;
-	}
+	if (!mcp->gc)
+		return -ENOMEM;
 
 	mcp->gc->label = "mcp2221_gpio";
 	mcp->gc->direction_input = mcp_gpio_direction_input;
@@ -900,26 +918,9 @@ static int mcp2221_probe(struct hid_device *hdev,
 
 	ret = devm_gpiochip_add_data(&hdev->dev, mcp->gc, mcp);
 	if (ret)
-		goto err_gc;
+		return ret;
 
 	return 0;
-
-err_gc:
-	i2c_del_adapter(&mcp->adapter);
-err_i2c:
-	hid_hw_close(mcp->hdev);
-err_hstop:
-	hid_hw_stop(mcp->hdev);
-	return ret;
-}
-
-static void mcp2221_remove(struct hid_device *hdev)
-{
-	struct mcp2221 *mcp = hid_get_drvdata(hdev);
-
-	i2c_del_adapter(&mcp->adapter);
-	hid_hw_close(mcp->hdev);
-	hid_hw_stop(mcp->hdev);
 }
 
 static const struct hid_device_id mcp2221_devices[] = {
-- 
2.37.2

[PATCH v5 5/5] HID: mcp2221: add ADC/DAC support via iio subsystem

[Matt Ranostay]

Add support for 3x 10-bit ADC and 1x DAC channels registered via the iio
subsystem.

To prevent breakage and unexpected dependencies this support only is
only built if CONFIG_IIO is enabled, and is only weakly referenced by
'imply IIO' within the respective Kconfig.

Additionally the iio device only gets registered if at least one channel
is enabled in the power-on configuration read from SRAM.

Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
---
 drivers/hid/Kconfig       |   1 +
 drivers/hid/hid-mcp2221.c | 258 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 258 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 6ce92830b5d1..8ee4a4a852a1 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -1299,6 +1299,7 @@ config HID_MCP2221
 	tristate "Microchip MCP2221 HID USB-to-I2C/SMbus host support"
 	depends on USB_HID && I2C
 	depends on GPIOLIB
+	imply IIO
 	help
 	Provides I2C and SMBUS host adapter functionality over USB-HID
 	through MCP2221 device.
diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c
index 3365e21547c6..fdffd12bc3b6 100644
--- a/drivers/hid/hid-mcp2221.c
+++ b/drivers/hid/hid-mcp2221.c
@@ -10,12 +10,14 @@
 #include <linux/module.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
+#include <linux/bitfield.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/hid.h>
 #include <linux/hidraw.h>
 #include <linux/i2c.h>
 #include <linux/gpio/driver.h>
+#include <linux/iio/iio.h>
 #include "hid-ids.h"
 
 /* Commands codes in a raw output report */
@@ -30,6 +32,9 @@ enum {
 	MCP2221_I2C_CANCEL = 0x10,
 	MCP2221_GPIO_SET = 0x50,
 	MCP2221_GPIO_GET = 0x51,
+	MCP2221_SET_SRAM_SETTINGS = 0x60,
+	MCP2221_GET_SRAM_SETTINGS = 0x61,
+	MCP2221_READ_FLASH_DATA = 0xb0,
 };
 
 /* Response codes in a raw input report */
@@ -89,6 +94,7 @@ struct mcp2221 {
 	struct i2c_adapter adapter;
 	struct mutex lock;
 	struct completion wait_in_report;
+	struct delayed_work init_work;
 	u8 *rxbuf;
 	u8 txbuf[64];
 	int rxbuf_idx;
@@ -97,6 +103,18 @@ struct mcp2221 {
 	struct gpio_chip *gc;
 	u8 gp_idx;
 	u8 gpio_dir;
+	u8 mode[4];
+#if IS_REACHABLE(CONFIG_IIO)
+	struct iio_chan_spec iio_channels[3];
+	u16 adc_values[3];
+	u8 adc_scale;
+	u8 dac_value;
+	u16 dac_scale;
+#endif
+};
+
+struct mcp2221_iio {
+	struct mcp2221 *mcp;
 };
 
 /*
@@ -713,7 +731,7 @@ static int mcp_get_i2c_eng_state(struct mcp2221 *mcp,
 static int mcp2221_raw_event(struct hid_device *hdev,
 				struct hid_report *report, u8 *data, int size)
 {
-	u8 *buf;
+	u8 *buf, tmp;
 	struct mcp2221 *mcp = hid_get_drvdata(hdev);
 
 	switch (data[0]) {
@@ -745,6 +763,9 @@ static int mcp2221_raw_event(struct hid_device *hdev,
 				break;
 			}
 			mcp->status = mcp_get_i2c_eng_state(mcp, data, 8);
+#if IS_REACHABLE(CONFIG_IIO)
+			memcpy(&mcp->adc_values, &data[50], sizeof(mcp->adc_values));
+#endif
 			break;
 		default:
 			mcp->status = -EIO;
@@ -816,6 +837,66 @@ static int mcp2221_raw_event(struct hid_device *hdev,
 		complete(&mcp->wait_in_report);
 		break;
 
+	case MCP2221_SET_SRAM_SETTINGS:
+		switch (data[1]) {
+		case MCP2221_SUCCESS:
+			mcp->status = 0;
+			break;
+		default:
+			mcp->status = -EAGAIN;
+		}
+		complete(&mcp->wait_in_report);
+		break;
+
+	case MCP2221_GET_SRAM_SETTINGS:
+		switch (data[1]) {
+		case MCP2221_SUCCESS:
+			memcpy(&mcp->mode, &data[22], 4);
+#if IS_REACHABLE(CONFIG_IIO)
+			mcp->dac_value = data[6] & GENMASK(4, 0);
+#endif
+			mcp->status = 0;
+			break;
+		default:
+			mcp->status = -EAGAIN;
+		}
+		complete(&mcp->wait_in_report);
+		break;
+
+	case MCP2221_READ_FLASH_DATA:
+		switch (data[1]) {
+		case MCP2221_SUCCESS:
+			mcp->status = 0;
+
+			/* Only handles CHIP SETTINGS subpage currently */
+			if (mcp->txbuf[1] != 0) {
+				mcp->status = -EIO;
+				break;
+			}
+
+#if IS_REACHABLE(CONFIG_IIO)
+			/* DAC scale value */
+			tmp = FIELD_GET(GENMASK(7, 6), data[6]);
+			if ((data[6] & BIT(5)) && tmp)
+				mcp->dac_scale = tmp + 4;
+			else
+				mcp->dac_scale = 5;
+
+			/* ADC scale value */
+			tmp = FIELD_GET(GENMASK(4, 3), data[7]);
+			if ((data[7] & BIT(2)) && tmp)
+				mcp->adc_scale = tmp - 1;
+			else
+				mcp->adc_scale = 0;
+#endif
+
+			break;
+		default:
+			mcp->status = -EAGAIN;
+		}
+		complete(&mcp->wait_in_report);
+		break;
+
 	default:
 		mcp->status = -EIO;
 		complete(&mcp->wait_in_report);
@@ -839,6 +920,176 @@ static void mcp2221_remove(struct hid_device *hdev)
 	return;
 }
 
+#if IS_REACHABLE(CONFIG_IIO)
+static int mcp2221_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *channel, int *val,
+			    int *val2, long mask)
+{
+	struct mcp2221_iio *priv = iio_priv(indio_dev);
+	struct mcp2221 *mcp = priv->mcp;
+	int ret;
+
+	if (mask == IIO_CHAN_INFO_SCALE) {
+		if (channel->output)
+			*val = 1 << mcp->dac_scale;
+		else
+			*val = 1 << mcp->adc_scale;
+
+		return IIO_VAL_INT;
+	}
+
+	mutex_lock(&mcp->lock);
+
+	if (channel->output) {
+		*val = mcp->dac_value;
+		ret = IIO_VAL_INT;
+	} else {
+		/* Read ADC values */
+		ret = mcp_chk_last_cmd_status(mcp);
+
+		if (!ret) {
+			*val = le16_to_cpu(mcp->adc_values[channel->address]);
+			if (*val >= BIT(10))
+				ret =  -EINVAL;
+			else
+				ret = IIO_VAL_INT;
+		}
+	}
+
+	mutex_unlock(&mcp->lock);
+
+	return ret;
+}
+
+static int mcp2221_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct mcp2221_iio *priv = iio_priv(indio_dev);
+	struct mcp2221 *mcp = priv->mcp;
+	int ret;
+
+	if (val < 0 || val >= BIT(5))
+		return -EINVAL;
+
+	mutex_lock(&mcp->lock);
+
+	memset(mcp->txbuf, 0, 12);
+	mcp->txbuf[0] = MCP2221_SET_SRAM_SETTINGS;
+	mcp->txbuf[4] = BIT(7) | val;
+
+	ret = mcp_send_data_req_status(mcp, mcp->txbuf, 12);
+	if (!ret)
+		mcp->dac_value = val;
+
+	mutex_unlock(&mcp->lock);
+
+	return ret;
+}
+
+static const struct iio_info mcp2221_info = {
+	.read_raw = &mcp2221_read_raw,
+	.write_raw = &mcp2221_write_raw,
+};
+
+static int mcp_iio_channels(struct mcp2221 *mcp)
+{
+	int idx, cnt = 0;
+	bool dac_created = false;
+
+	/* GP0 doesn't have ADC/DAC alternative function */
+	for (idx = 1; idx < MCP_NGPIO; idx++) {
+		struct iio_chan_spec *chan = &mcp->iio_channels[cnt];
+
+		switch (mcp->mode[idx]) {
+		case 2:
+			chan->address = idx - 1;
+			chan->channel = cnt++;
+			break;
+		case 3:
+			/* GP1 doesn't have DAC alternative function */
+			if (idx == 1 || dac_created)
+				continue;
+			/* DAC1 and DAC2 outputs are connected to the same DAC */
+			dac_created = true;
+			chan->output = 1;
+			cnt++;
+			break;
+		default:
+			continue;
+		};
+
+		chan->type = IIO_VOLTAGE;
+		chan->indexed = 1;
+		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+		chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
+		chan->scan_index = -1;
+	}
+
+	return cnt;
+}
+
+static void mcp_init_work(struct work_struct *work)
+{
+	struct iio_dev *indio_dev;
+	struct mcp2221 *mcp = container_of(work, struct mcp2221, init_work.work);
+	struct mcp2221_iio *data;
+	static int retries = 5;
+	int ret, num_channels;
+
+	hid_hw_power(mcp->hdev, PM_HINT_FULLON);
+	mutex_lock(&mcp->lock);
+
+	mcp->txbuf[0] = MCP2221_GET_SRAM_SETTINGS;
+	ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
+
+	if (ret == -EAGAIN)
+		goto reschedule_task;
+
+	num_channels = mcp_iio_channels(mcp);
+	if (!num_channels)
+		goto unlock;
+
+	mcp->txbuf[0] = MCP2221_READ_FLASH_DATA;
+	mcp->txbuf[1] = 0;
+	ret = mcp_send_data_req_status(mcp, mcp->txbuf, 2);
+
+	if (ret == -EAGAIN)
+		goto reschedule_task;
+
+	indio_dev = devm_iio_device_alloc(&mcp->hdev->dev, sizeof(*data));
+	if (!indio_dev)
+		goto unlock;
+
+	data = iio_priv(indio_dev);
+	data->mcp = mcp;
+
+	indio_dev->name = "mcp2221";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &mcp2221_info;
+	indio_dev->channels = mcp->iio_channels;
+	indio_dev->num_channels = num_channels;
+
+	devm_iio_device_register(&mcp->hdev->dev, indio_dev);
+
+unlock:
+	mutex_unlock(&mcp->lock);
+	hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
+
+	return;
+
+reschedule_task:
+	mutex_unlock(&mcp->lock);
+	hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
+
+	if (!retries--)
+		return;
+
+	/* Device is not ready to read SRAM or FLASH data, try again */
+	schedule_delayed_work(&mcp->init_work, msecs_to_jiffies(100));
+}
+#endif
+
 static int mcp2221_probe(struct hid_device *hdev,
 					const struct hid_device_id *id)
 {
@@ -920,6 +1171,11 @@ static int mcp2221_probe(struct hid_device *hdev,
 	if (ret)
 		return ret;
 
+#if IS_REACHABLE(CONFIG_IIO)
+	INIT_DELAYED_WORK(&mcp->init_work, mcp_init_work);
+	schedule_delayed_work(&mcp->init_work, msecs_to_jiffies(100));
+#endif
+
 	return 0;
 }
 
-- 
2.37.2

Re: [PATCH v5 1/5] i2c: muxes: ltc4306: fix future recursive dependencies

[Peter Rosin]

Hi!

2022-09-27 at 04:50, Matt Ranostay wrote:
> When using 'imply IIO' for other configurations which have 'select GPIOLIB'
> the following recursive dependency is detected for I2C_MUX_LTC4306
> 
> Switch from 'select GPIOLIB' to 'depends on GPIOLIB' to avoid this per
> recommendation in kconfig-language.rst

I find that it is a bit sad and unfriendly that drivers are hidden from
the user unless the user has previously selected GPIOLIB. Configuring the
kernel is bad as it is. Since GPIOLIB is not really a strong dependency
for this driver (at least I think the device may function well enough
without GPIO support) couldn't the mcp2221 driver "imply GPIOLIB" as well?

Then it's only one driver that is affected and not a set of random drivers
like this.

Cheers,
Peter

> drivers/gpio/Kconfig:14:error: recursive dependency detected!
> drivers/gpio/Kconfig:14:        symbol GPIOLIB is selected by I2C_MUX_LTC4306
> drivers/i2c/muxes/Kconfig:47:   symbol I2C_MUX_LTC4306 depends on I2C_MUX
> drivers/i2c/Kconfig:62: symbol I2C_MUX is selected by MPU3050_I2C
> drivers/iio/gyro/Kconfig:127:   symbol MPU3050_I2C depends on IIO
> drivers/iio/Kconfig:6:  symbol IIO is implied by HID_MCP2221
> drivers/hid/Kconfig:1227:       symbol HID_MCP2221 depends on GPIOLIB
> 
> Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
> ---
>  drivers/i2c/muxes/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
> index 1708b1a82da2..8642ea8e0a3d 100644
> --- a/drivers/i2c/muxes/Kconfig
> +++ b/drivers/i2c/muxes/Kconfig
> @@ -46,7 +46,7 @@ config I2C_MUX_GPMUX
>  
>  config I2C_MUX_LTC4306
>  	tristate "LTC LTC4306/5 I2C multiplexer"
> -	select GPIOLIB
> +	depends on GPIOLIB
>  	select REGMAP_I2C
>  	help
>  	  If you say yes here you get support for the Analog Devices