* [PATCH] HID: mcp2221: add ADC support
@ 2020-11-20 3:01 Matt Ranostay
2020-11-20 13:14 ` rishi gupta
0 siblings, 1 reply; 6+ messages in thread
From: Matt Ranostay @ 2020-11-20 3:01 UTC (permalink / raw)
To: linux-iio, linux-input; +Cc: Matt Ranostay, Rishi Gupta
Add support for the three 10-bit ADC channels registered via
the IIO subsystem.
Cc: linux-input@vger.kernel.org
Cc: linux-iio@vger.kernel.org
CC: Rishi Gupta <gupt21@gmail.com>
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
---
drivers/hid/Kconfig | 1 +
drivers/hid/hid-mcp2221.c | 65 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 65 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 05315b434276..4795744d9979 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -1157,6 +1157,7 @@ config HID_MCP2221
tristate "Microchip MCP2221 HID USB-to-I2C/SMbus host support"
depends on USB_HID && I2C
depends on GPIOLIB
+ depends on 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 0d27ccb55dd9..7e62f1dc54d3 100644
--- a/drivers/hid/hid-mcp2221.c
+++ b/drivers/hid/hid-mcp2221.c
@@ -18,6 +18,9 @@
#include <linux/gpio/driver.h>
#include "hid-ids.h"
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
/* Commands codes in a raw output report */
enum {
MCP2221_I2C_WR_DATA = 0x90,
@@ -56,6 +59,7 @@ enum {
*/
struct mcp2221 {
struct hid_device *hdev;
+ struct iio_dev *indio_dev;
struct i2c_adapter adapter;
struct mutex lock;
struct completion wait_in_report;
@@ -67,6 +71,11 @@ struct mcp2221 {
struct gpio_chip *gc;
u8 gp_idx;
u8 gpio_dir;
+ u16 adc_values[3];
+};
+
+struct mcp2221_iio {
+ struct mcp2221 *mcp;
};
/*
@@ -712,6 +721,7 @@ static int mcp2221_raw_event(struct hid_device *hdev,
break;
}
mcp->status = mcp_get_i2c_eng_state(mcp, data, 8);
+ memcpy(&mcp->adc_values, &data[50], 6);
break;
default:
mcp->status = -EIO;
@@ -791,11 +801,54 @@ static int mcp2221_raw_event(struct hid_device *hdev,
return 1;
}
+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;
+
+ mutex_lock(&mcp->lock);
+
+ /* Read ADC values */
+ ret = mcp_chk_last_cmd_status(mcp);
+ if (ret < 0)
+ return ret;
+
+ *val = le16_to_cpu(mcp->adc_values[channel->channel]);
+
+ mutex_unlock(&mcp->lock);
+
+ return IIO_VAL_INT;
+}
+
+static const struct iio_info mcp2221_info = {
+ .read_raw = &mcp2221_read_raw,
+};
+
+#define MCP2221_ADC_CHANNEL(idx) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = idx, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .scan_index = -1, \
+ }
+
+static const struct iio_chan_spec mcp2221_channels[] = {
+ MCP2221_ADC_CHANNEL(0),
+ MCP2221_ADC_CHANNEL(1),
+ MCP2221_ADC_CHANNEL(2),
+};
+
static int mcp2221_probe(struct hid_device *hdev,
const struct hid_device_id *id)
{
int ret;
struct mcp2221 *mcp;
+ struct mcp2221_iio *iio;
mcp = devm_kzalloc(&hdev->dev, sizeof(*mcp), GFP_KERNEL);
if (!mcp)
@@ -869,8 +922,17 @@ static int mcp2221_probe(struct hid_device *hdev,
if (ret)
goto err_gc;
- return 0;
+ mcp->indio_dev = devm_iio_device_alloc(&hdev->dev, sizeof(*iio));
+ iio = iio_priv(mcp->indio_dev);
+ iio->mcp = mcp;
+
+ mcp->indio_dev->name = "mcp2221_adc";
+ mcp->indio_dev->modes = INDIO_DIRECT_MODE;
+ mcp->indio_dev->info = &mcp2221_info;
+ mcp->indio_dev->channels = mcp2221_channels;
+ mcp->indio_dev->num_channels = ARRAY_SIZE(mcp2221_channels);
+ return iio_device_register(mcp->indio_dev);
err_gc:
i2c_del_adapter(&mcp->adapter);
err_i2c:
@@ -884,6 +946,7 @@ static void mcp2221_remove(struct hid_device *hdev)
{
struct mcp2221 *mcp = hid_get_drvdata(hdev);
+ iio_device_unregister(mcp->indio_dev);
i2c_del_adapter(&mcp->adapter);
hid_hw_close(mcp->hdev);
hid_hw_stop(mcp->hdev);
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] HID: mcp2221: add ADC support
2020-11-20 3:01 [PATCH] HID: mcp2221: add ADC support Matt Ranostay
@ 2020-11-20 13:14 ` rishi gupta
2020-11-20 19:17 ` Matt Ranostay
0 siblings, 1 reply; 6+ messages in thread
From: rishi gupta @ 2020-11-20 13:14 UTC (permalink / raw)
To: Matt Ranostay; +Cc: linux-iio, open list:HID CORE LAYER
On Fri, Nov 20, 2020 at 8:31 AM Matt Ranostay
<matt.ranostay@konsulko.com> wrote:
>
> Add support for the three 10-bit ADC channels registered via
> the IIO subsystem.
>
> Cc: linux-input@vger.kernel.org
> Cc: linux-iio@vger.kernel.org
> CC: Rishi Gupta <gupt21@gmail.com>
> Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
> ---
> drivers/hid/Kconfig | 1 +
> drivers/hid/hid-mcp2221.c | 65 ++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 65 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> index 05315b434276..4795744d9979 100644
> --- a/drivers/hid/Kconfig
> +++ b/drivers/hid/Kconfig
> @@ -1157,6 +1157,7 @@ config HID_MCP2221
> tristate "Microchip MCP2221 HID USB-to-I2C/SMbus host support"
> depends on USB_HID && I2C
> depends on GPIOLIB
> + depends on IIO
I am wondering what will happen on systems which do not enable IIO.
This driver can not be used there.
Is my understanding correct?
> 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 0d27ccb55dd9..7e62f1dc54d3 100644
> --- a/drivers/hid/hid-mcp2221.c
> +++ b/drivers/hid/hid-mcp2221.c
> @@ -18,6 +18,9 @@
> #include <linux/gpio/driver.h>
> #include "hid-ids.h"
>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> /* Commands codes in a raw output report */
> enum {
> MCP2221_I2C_WR_DATA = 0x90,
> @@ -56,6 +59,7 @@ enum {
> */
> struct mcp2221 {
> struct hid_device *hdev;
> + struct iio_dev *indio_dev;
> struct i2c_adapter adapter;
> struct mutex lock;
> struct completion wait_in_report;
> @@ -67,6 +71,11 @@ struct mcp2221 {
> struct gpio_chip *gc;
> u8 gp_idx;
> u8 gpio_dir;
> + u16 adc_values[3];
> +};
> +
> +struct mcp2221_iio {
> + struct mcp2221 *mcp;
> };
>
> /*
> @@ -712,6 +721,7 @@ static int mcp2221_raw_event(struct hid_device *hdev,
> break;
> }
> mcp->status = mcp_get_i2c_eng_state(mcp, data, 8);
> + memcpy(&mcp->adc_values, &data[50], 6);
> break;
> default:
> mcp->status = -EIO;
> @@ -791,11 +801,54 @@ static int mcp2221_raw_event(struct hid_device *hdev,
> return 1;
> }
>
> +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;
> +
> + mutex_lock(&mcp->lock);
> +
> + /* Read ADC values */
> + ret = mcp_chk_last_cmd_status(mcp);
> + if (ret < 0)
> + return ret;
> +
> + *val = le16_to_cpu(mcp->adc_values[channel->channel]);
> +
> + mutex_unlock(&mcp->lock);
> +
> + return IIO_VAL_INT;
> +}
> +
> +static const struct iio_info mcp2221_info = {
> + .read_raw = &mcp2221_read_raw,
> +};
> +
> +#define MCP2221_ADC_CHANNEL(idx) \
> + { \
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
> + .channel = idx, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .scan_index = -1, \
> + }
> +
> +static const struct iio_chan_spec mcp2221_channels[] = {
> + MCP2221_ADC_CHANNEL(0),
> + MCP2221_ADC_CHANNEL(1),
> + MCP2221_ADC_CHANNEL(2),
> +};
> +
> static int mcp2221_probe(struct hid_device *hdev,
> const struct hid_device_id *id)
> {
> int ret;
> struct mcp2221 *mcp;
> + struct mcp2221_iio *iio;
>
> mcp = devm_kzalloc(&hdev->dev, sizeof(*mcp), GFP_KERNEL);
> if (!mcp)
> @@ -869,8 +922,17 @@ static int mcp2221_probe(struct hid_device *hdev,
> if (ret)
> goto err_gc;
>
> - return 0;
> + mcp->indio_dev = devm_iio_device_alloc(&hdev->dev, sizeof(*iio));
> + iio = iio_priv(mcp->indio_dev);
> + iio->mcp = mcp;
> +
> + mcp->indio_dev->name = "mcp2221_adc";
> + mcp->indio_dev->modes = INDIO_DIRECT_MODE;
> + mcp->indio_dev->info = &mcp2221_info;
> + mcp->indio_dev->channels = mcp2221_channels;
> + mcp->indio_dev->num_channels = ARRAY_SIZE(mcp2221_channels);
>
> + return iio_device_register(mcp->indio_dev);
> err_gc:
> i2c_del_adapter(&mcp->adapter);
> err_i2c:
> @@ -884,6 +946,7 @@ static void mcp2221_remove(struct hid_device *hdev)
> {
> struct mcp2221 *mcp = hid_get_drvdata(hdev);
>
> + iio_device_unregister(mcp->indio_dev);
> i2c_del_adapter(&mcp->adapter);
> hid_hw_close(mcp->hdev);
> hid_hw_stop(mcp->hdev);
> --
> 2.20.1
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] HID: mcp2221: add ADC support
2020-11-20 13:14 ` rishi gupta
@ 2020-11-20 19:17 ` Matt Ranostay
2020-11-20 19:54 ` Lars-Peter Clausen
0 siblings, 1 reply; 6+ messages in thread
From: Matt Ranostay @ 2020-11-20 19:17 UTC (permalink / raw)
To: rishi gupta; +Cc: open list:IIO SUBSYSTEM AND DRIVERS, open list:HID CORE LAYER
On Fri, Nov 20, 2020 at 5:15 AM rishi gupta <gupt21@gmail.com> wrote:
>
> On Fri, Nov 20, 2020 at 8:31 AM Matt Ranostay
> <matt.ranostay@konsulko.com> wrote:
> >
> > Add support for the three 10-bit ADC channels registered via
> > the IIO subsystem.
> >
> > Cc: linux-input@vger.kernel.org
> > Cc: linux-iio@vger.kernel.org
> > CC: Rishi Gupta <gupt21@gmail.com>
> > Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
> > ---
> > drivers/hid/Kconfig | 1 +
> > drivers/hid/hid-mcp2221.c | 65 ++++++++++++++++++++++++++++++++++++++-
> > 2 files changed, 65 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> > index 05315b434276..4795744d9979 100644
> > --- a/drivers/hid/Kconfig
> > +++ b/drivers/hid/Kconfig
> > @@ -1157,6 +1157,7 @@ config HID_MCP2221
> > tristate "Microchip MCP2221 HID USB-to-I2C/SMbus host support"
> > depends on USB_HID && I2C
> > depends on GPIOLIB
> > + depends on IIO
> I am wondering what will happen on systems which do not enable IIO.
> This driver can not be used there.
> Is my understanding correct?
Actually yeah this should be "select IIO" to avoid that issue.
- Matt
> > 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 0d27ccb55dd9..7e62f1dc54d3 100644
> > --- a/drivers/hid/hid-mcp2221.c
> > +++ b/drivers/hid/hid-mcp2221.c
> > @@ -18,6 +18,9 @@
> > #include <linux/gpio/driver.h>
> > #include "hid-ids.h"
> >
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/sysfs.h>
> > +
> > /* Commands codes in a raw output report */
> > enum {
> > MCP2221_I2C_WR_DATA = 0x90,
> > @@ -56,6 +59,7 @@ enum {
> > */
> > struct mcp2221 {
> > struct hid_device *hdev;
> > + struct iio_dev *indio_dev;
> > struct i2c_adapter adapter;
> > struct mutex lock;
> > struct completion wait_in_report;
> > @@ -67,6 +71,11 @@ struct mcp2221 {
> > struct gpio_chip *gc;
> > u8 gp_idx;
> > u8 gpio_dir;
> > + u16 adc_values[3];
> > +};
> > +
> > +struct mcp2221_iio {
> > + struct mcp2221 *mcp;
> > };
> >
> > /*
> > @@ -712,6 +721,7 @@ static int mcp2221_raw_event(struct hid_device *hdev,
> > break;
> > }
> > mcp->status = mcp_get_i2c_eng_state(mcp, data, 8);
> > + memcpy(&mcp->adc_values, &data[50], 6);
> > break;
> > default:
> > mcp->status = -EIO;
> > @@ -791,11 +801,54 @@ static int mcp2221_raw_event(struct hid_device *hdev,
> > return 1;
> > }
> >
> > +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;
> > +
> > + mutex_lock(&mcp->lock);
> > +
> > + /* Read ADC values */
> > + ret = mcp_chk_last_cmd_status(mcp);
> > + if (ret < 0)
> > + return ret;
> > +
> > + *val = le16_to_cpu(mcp->adc_values[channel->channel]);
> > +
> > + mutex_unlock(&mcp->lock);
> > +
> > + return IIO_VAL_INT;
> > +}
> > +
> > +static const struct iio_info mcp2221_info = {
> > + .read_raw = &mcp2221_read_raw,
> > +};
> > +
> > +#define MCP2221_ADC_CHANNEL(idx) \
> > + { \
> > + .type = IIO_VOLTAGE, \
> > + .indexed = 1, \
> > + .channel = idx, \
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> > + .scan_index = -1, \
> > + }
> > +
> > +static const struct iio_chan_spec mcp2221_channels[] = {
> > + MCP2221_ADC_CHANNEL(0),
> > + MCP2221_ADC_CHANNEL(1),
> > + MCP2221_ADC_CHANNEL(2),
> > +};
> > +
> > static int mcp2221_probe(struct hid_device *hdev,
> > const struct hid_device_id *id)
> > {
> > int ret;
> > struct mcp2221 *mcp;
> > + struct mcp2221_iio *iio;
> >
> > mcp = devm_kzalloc(&hdev->dev, sizeof(*mcp), GFP_KERNEL);
> > if (!mcp)
> > @@ -869,8 +922,17 @@ static int mcp2221_probe(struct hid_device *hdev,
> > if (ret)
> > goto err_gc;
> >
> > - return 0;
> > + mcp->indio_dev = devm_iio_device_alloc(&hdev->dev, sizeof(*iio));
> > + iio = iio_priv(mcp->indio_dev);
> > + iio->mcp = mcp;
> > +
> > + mcp->indio_dev->name = "mcp2221_adc";
> > + mcp->indio_dev->modes = INDIO_DIRECT_MODE;
> > + mcp->indio_dev->info = &mcp2221_info;
> > + mcp->indio_dev->channels = mcp2221_channels;
> > + mcp->indio_dev->num_channels = ARRAY_SIZE(mcp2221_channels);
> >
> > + return iio_device_register(mcp->indio_dev);
> > err_gc:
> > i2c_del_adapter(&mcp->adapter);
> > err_i2c:
> > @@ -884,6 +946,7 @@ static void mcp2221_remove(struct hid_device *hdev)
> > {
> > struct mcp2221 *mcp = hid_get_drvdata(hdev);
> >
> > + iio_device_unregister(mcp->indio_dev);
> > i2c_del_adapter(&mcp->adapter);
> > hid_hw_close(mcp->hdev);
> > hid_hw_stop(mcp->hdev);
> > --
> > 2.20.1
> >
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] HID: mcp2221: add ADC support
2020-11-20 19:17 ` Matt Ranostay
@ 2020-11-20 19:54 ` Lars-Peter Clausen
2020-11-20 20:31 ` Matt Ranostay
0 siblings, 1 reply; 6+ messages in thread
From: Lars-Peter Clausen @ 2020-11-20 19:54 UTC (permalink / raw)
To: Matt Ranostay, rishi gupta
Cc: open list:IIO SUBSYSTEM AND DRIVERS, open list:HID CORE LAYER
On 11/20/20 8:17 PM, Matt Ranostay wrote:
> On Fri, Nov 20, 2020 at 5:15 AM rishi gupta <gupt21@gmail.com> wrote:
>> On Fri, Nov 20, 2020 at 8:31 AM Matt Ranostay
>> <matt.ranostay@konsulko.com> wrote:
>>> Add support for the three 10-bit ADC channels registered via
>>> the IIO subsystem.
>>>
>>> Cc: linux-input@vger.kernel.org
>>> Cc: linux-iio@vger.kernel.org
>>> CC: Rishi Gupta <gupt21@gmail.com>
>>> Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
>>> ---
>>> drivers/hid/Kconfig | 1 +
>>> drivers/hid/hid-mcp2221.c | 65 ++++++++++++++++++++++++++++++++++++++-
>>> 2 files changed, 65 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
>>> index 05315b434276..4795744d9979 100644
>>> --- a/drivers/hid/Kconfig
>>> +++ b/drivers/hid/Kconfig
>>> @@ -1157,6 +1157,7 @@ config HID_MCP2221
>>> tristate "Microchip MCP2221 HID USB-to-I2C/SMbus host support"
>>> depends on USB_HID && I2C
>>> depends on GPIOLIB
>>> + depends on IIO
>> I am wondering what will happen on systems which do not enable IIO.
>> This driver can not be used there.
>> Is my understanding correct?
> Actually yeah this should be "select IIO" to avoid that issue.
No, we should not have a individual driver select a framework. This will
cause all kinds of issues with reverse dependencies.
It might be worth splitting this driver into a MFD driver, then the MFD
cells could have their own module that depend on the subsystem and if
not enabled the functionality will not be provided.
- Lars
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] HID: mcp2221: add ADC support
2020-11-20 19:54 ` Lars-Peter Clausen
@ 2020-11-20 20:31 ` Matt Ranostay
2020-11-21 15:10 ` Jonathan Cameron
0 siblings, 1 reply; 6+ messages in thread
From: Matt Ranostay @ 2020-11-20 20:31 UTC (permalink / raw)
To: Lars-Peter Clausen
Cc: rishi gupta, open list:IIO SUBSYSTEM AND DRIVERS,
open list:HID CORE LAYER
On Fri, Nov 20, 2020 at 11:54 AM Lars-Peter Clausen <lars@metafoo.de> wrote:
>
> On 11/20/20 8:17 PM, Matt Ranostay wrote:
> > On Fri, Nov 20, 2020 at 5:15 AM rishi gupta <gupt21@gmail.com> wrote:
> >> On Fri, Nov 20, 2020 at 8:31 AM Matt Ranostay
> >> <matt.ranostay@konsulko.com> wrote:
> >>> Add support for the three 10-bit ADC channels registered via
> >>> the IIO subsystem.
> >>>
> >>> Cc: linux-input@vger.kernel.org
> >>> Cc: linux-iio@vger.kernel.org
> >>> CC: Rishi Gupta <gupt21@gmail.com>
> >>> Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
> >>> ---
> >>> drivers/hid/Kconfig | 1 +
> >>> drivers/hid/hid-mcp2221.c | 65 ++++++++++++++++++++++++++++++++++++++-
> >>> 2 files changed, 65 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> >>> index 05315b434276..4795744d9979 100644
> >>> --- a/drivers/hid/Kconfig
> >>> +++ b/drivers/hid/Kconfig
> >>> @@ -1157,6 +1157,7 @@ config HID_MCP2221
> >>> tristate "Microchip MCP2221 HID USB-to-I2C/SMbus host support"
> >>> depends on USB_HID && I2C
> >>> depends on GPIOLIB
> >>> + depends on IIO
> >> I am wondering what will happen on systems which do not enable IIO.
> >> This driver can not be used there.
> >> Is my understanding correct?
> > Actually yeah this should be "select IIO" to avoid that issue.
>
> No, we should not have a individual driver select a framework. This will
> cause all kinds of issues with reverse dependencies.
>
> It might be worth splitting this driver into a MFD driver, then the MFD
> cells could have their own module that depend on the subsystem and if
> not enabled the functionality will not be provided.
Would it make sense to use IS_REACHABLE(CONFIG_IIO) for the iio blocks?
Guessing the weak reference "imply IIO" would still be bad for the
driver selecting a framework?
Thanks,
Matt
>
> - Lars
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] HID: mcp2221: add ADC support
2020-11-20 20:31 ` Matt Ranostay
@ 2020-11-21 15:10 ` Jonathan Cameron
0 siblings, 0 replies; 6+ messages in thread
From: Jonathan Cameron @ 2020-11-21 15:10 UTC (permalink / raw)
To: Matt Ranostay
Cc: Lars-Peter Clausen, rishi gupta,
open list:IIO SUBSYSTEM AND DRIVERS, open list:HID CORE LAYER
On Fri, 20 Nov 2020 12:31:23 -0800
Matt Ranostay <matt.ranostay@konsulko.com> wrote:
> On Fri, Nov 20, 2020 at 11:54 AM Lars-Peter Clausen <lars@metafoo.de> wrote:
> >
> > On 11/20/20 8:17 PM, Matt Ranostay wrote:
> > > On Fri, Nov 20, 2020 at 5:15 AM rishi gupta <gupt21@gmail.com> wrote:
> > >> On Fri, Nov 20, 2020 at 8:31 AM Matt Ranostay
> > >> <matt.ranostay@konsulko.com> wrote:
> > >>> Add support for the three 10-bit ADC channels registered via
> > >>> the IIO subsystem.
> > >>>
> > >>> Cc: linux-input@vger.kernel.org
> > >>> Cc: linux-iio@vger.kernel.org
> > >>> CC: Rishi Gupta <gupt21@gmail.com>
> > >>> Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
> > >>> ---
> > >>> drivers/hid/Kconfig | 1 +
> > >>> drivers/hid/hid-mcp2221.c | 65 ++++++++++++++++++++++++++++++++++++++-
> > >>> 2 files changed, 65 insertions(+), 1 deletion(-)
> > >>>
> > >>> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> > >>> index 05315b434276..4795744d9979 100644
> > >>> --- a/drivers/hid/Kconfig
> > >>> +++ b/drivers/hid/Kconfig
> > >>> @@ -1157,6 +1157,7 @@ config HID_MCP2221
> > >>> tristate "Microchip MCP2221 HID USB-to-I2C/SMbus host support"
> > >>> depends on USB_HID && I2C
> > >>> depends on GPIOLIB
> > >>> + depends on IIO
> > >> I am wondering what will happen on systems which do not enable IIO.
> > >> This driver can not be used there.
> > >> Is my understanding correct?
> > > Actually yeah this should be "select IIO" to avoid that issue.
> >
> > No, we should not have a individual driver select a framework. This will
> > cause all kinds of issues with reverse dependencies.
> >
> > It might be worth splitting this driver into a MFD driver, then the MFD
> > cells could have their own module that depend on the subsystem and if
> > not enabled the functionality will not be provided.
>
> Would it make sense to use IS_REACHABLE(CONFIG_IIO) for the iio blocks?
>
> Guessing the weak reference "imply IIO" would still be bad for the
> driver selecting a framework?
A lesser option than going full MFD for this (which is probably the
right design decision but is a big change) would be to just put the
IIO stuff in a separate C file and use some build time magic.
I agree with Lars though that this is probably better done as an MFD.
It supports a bunch of things in entirely different subsystems afterall.
Jonathan
>
> Thanks,
>
> Matt
>
> >
> > - Lars
> >
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-11-21 15:10 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-11-20 3:01 [PATCH] HID: mcp2221: add ADC support Matt Ranostay
2020-11-20 13:14 ` rishi gupta
2020-11-20 19:17 ` Matt Ranostay
2020-11-20 19:54 ` Lars-Peter Clausen
2020-11-20 20:31 ` Matt Ranostay
2020-11-21 15:10 ` Jonathan Cameron
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