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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: Linus Walleij <linusw@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
master
Linus Walleij 2026-02-18 14:44:38 +01:00 committed by Jiri Kosina
parent ab05515757
commit 200e6c6e94
1 changed files with 14 additions and 4 deletions
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18
drivers/hid/hid-mcp2221.c
View File

@ -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);
@ -1043,7 +1050,8 @@ static void mcp2221_remove(struct hid_device *hdev)
#if IS_REACHABLE(CONFIG_IIO)
struct mcp2221 *mcp = hid_get_drvdata(hdev);
cancel_delayed_work_sync(&mcp->init_work);
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)
INIT_DELAYED_WORK(&mcp->init_work, mcp_init_work);
schedule_delayed_work(&mcp->init_work, msecs_to_jiffies(100));
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;