Commit 200e6c6e authored by Linus Walleij's avatar Linus Walleij Committed by Jiri Kosina
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HID: mcp2221: Add module parameter to enfoce GPIO mode 



Add a module parameter to MCP2221 to enfor GPIO mode on the
general purpose pins GP0 thru GP3.

If I plug a device of this type into my machine, it will use the
GP0, GP1, GP2 and GP3 pins for IIO voltage readings by default
if CONFIG_IIO is set.

However there may be cases where IIO is available but we want to
use the GP0 thru GP3 lines for GPIO anyway.

Example use:

insmode hid-mcp2221.ko gpio_mode_enforce=1

Result in dmesg:
mcp2221 0003:04D8:00DD.0005: GPIO 0 not in gpio mode
mcp2221 0003:04D8:00DD.0005: GPIO 1 not in gpio mode
mcp2221 0003:04D8:00DD.0005: GPIO 2 not in gpio mode
mcp2221 0003:04D8:00DD.0005: GPIO 3 not in gpio mode
mcp2221 0003:04D8:00DD.0005: Set GPIO mode for gpio pin 0!
mcp2221 0003:04D8:00DD.0005: Set GPIO mode for gpio pin 1!
mcp2221 0003:04D8:00DD.0005: Set GPIO mode for gpio pin 2!
mcp2221 0003:04D8:00DD.0005: Set GPIO mode for gpio pin 3!

After this the gpiolib tools such as gpioset can be used to alter
the GPIO line values successfully.

Signed-off-by: default avatarLinus Walleij <linusw@kernel.org>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.com>
parent ab055157

drivers/hid/hid-mcp2221.c

+14 −4
Original line number Diff line number Diff line
@@ -19,8 +19,15 @@ 
#include <linux/gpio/driver.h>

#include <linux/iio/iio.h>

#include <linux/minmax.h>

#include <linux/moduleparam.h>

#include "hid-ids.h"



static bool gpio_mode_enforce;



module_param(gpio_mode_enforce, bool, 0644);

MODULE_PARM_DESC(gpio_mode_enforce,

	 "Enfore GPIO mode for GP0 thru GP3 (default: false, will be used for IIO)");



/* Commands codes in a raw output report */

enum {

	MCP2221_I2C_WR_DATA = 0x90,
@@ -648,7 +655,7 @@ static int mcp2221_check_gpio_pinfunc(struct mcp2221 *mcp) 
	int needgpiofix = 0;

	int ret;



	if (IS_ENABLED(CONFIG_IIO))

	if (IS_ENABLED(CONFIG_IIO) && !gpio_mode_enforce)

		return 0;



	ret = mcp_gpio_read_sram(mcp);
@@ -1043,6 +1050,7 @@ static void mcp2221_remove(struct hid_device *hdev) 
#if IS_REACHABLE(CONFIG_IIO)

	struct mcp2221 *mcp = hid_get_drvdata(hdev);



	if (!gpio_mode_enforce)

		cancel_delayed_work_sync(&mcp->init_work);

#endif

}
@@ -1317,8 +1325,10 @@ static int mcp2221_probe(struct hid_device *hdev, 
#endif



#if IS_REACHABLE(CONFIG_IIO)

	if (!gpio_mode_enforce) {

		INIT_DELAYED_WORK(&mcp->init_work, mcp_init_work);

		schedule_delayed_work(&mcp->init_work, msecs_to_jiffies(100));

	}

#endif



	return 0;