Re: [PATCH] joydev.c: Digital joysticks on analog ports

From: Vojtech Pavlik
Date: Thu Jul 07 2005 - 07:15:02 EST

On Thu, Jul 07, 2005 at 01:14:58PM +0200, Thomas Richter wrote:
>
> Hi folks, hi Vojtech,
>
> the following is a patch to drivers/input/joydev.c and
> include/linux/joystick.h that allows you to connect the "traditional"
> digital joysticks for C64, Atari, Amiga... on analog input ports by
> means of a minimalistic self- made adapter board ("ElCheapo",
> schematics below). The patch converts the digital inputs to suitable
> "analog" versions that are interpreted fine. The patch "as is" applies
> to kernel 2.4.31, but it should work for other kernel versions as
> well.
>
> New kernel parameters for joydev: "digital = 1" sets all default input
> modes to "digital" instead of analog.
>
> The new ioctl JSIOCSDIGITAL for joydev allows to adjusts this
> on the running driver.

Sorry, I have to reject this patch.

First, you added support for the adapter to the wrong file - if
anywhere, the logic should be either inside analog.c, or in a separate
driver, which would be probably better.

Second, the 2.4 input layer is in bugfix-only mode now. Any new features
can go only into 2.6.

Third - the ElCheapo interface is totally ugly. With just a few more
component a real convertor, working as a real joystick is possible.

Fourth - we already have three drivers for these joystick (db9, gamecon
and turbografx), all connected via trivial circuits to the parallel
port.

> Greetings,
> Thomas Richter
>
> Patch for drivers/input/joydev.c:
>
> /* snip */
>
> --- ../linux-2.4.31/drivers/input/joydev.c 2003-06-13 16:51:34.000000000 +0200
> +++ drivers/input/joydev.c 2005-07-06 22:37:21.000000000 +0200
> @@ -65,6 +65,7 @@
> struct JS_DATA_SAVE_TYPE glue;
> int nabs;
> int nkey;
> + int digital;
> __u16 keymap[KEY_MAX - BTN_MISC];
> __u16 keypam[KEY_MAX - BTN_MISC];
> __u8 absmap[ABS_MAX];
> @@ -84,6 +85,11 @@
>
> static struct joydev *joydev_table[JOYDEV_MINORS];
>
> +static int digital = 0;
> +
> +MODULE_PARM(digital,"i");
> +MODULE_PARM_DESC(digital,"if 1, handle digital joysticks via the 'ElCheapo' interface");
> +
> MODULE_AUTHOR("Vojtech Pavlik <vojtech@xxxxxxx>");
> MODULE_DESCRIPTION("Joystick device driver");
> MODULE_LICENSE("GPL");
> @@ -109,13 +115,68 @@
> return value;
> }
>
> +static int joydev_digital_event(struct js_event *ev,struct input_handle *handle,unsigned int type,
> + unsigned int code, int value)
> +{
> + struct joydev *joydev = handle->private;
> +
> + switch(type) {
> + case EV_KEY:
> + if (code < BTN_MISC || value == 2) return 0;
> + code = joydev->keymap[code - BTN_MISC];
> + switch(code) {
> + case 0:
> + ev->type = JS_EVENT_AXIS;
> + ev->number = 1;
> + ev->value = (value)?+32767:0;
> + break;
> + case 1:
> + ev->type = JS_EVENT_AXIS;
> + ev->number = 0;
> + ev->value = (value)?+32767:0;
> + break;
> + case 2:
> + ev->type = JS_EVENT_AXIS;
> + ev->number = 1;
> + ev->value = (value)?-32767:0;
> + break;
> + case 3:
> + ev->type = JS_EVENT_AXIS;
> + ev->number = 0;
> + ev->value = (value)?-32767:0;
> + break;
> + default:
> + ev->type = JS_EVENT_BUTTON;
> + ev->number = code;
> + ev->value = value;
> + }
> + break;
> + case EV_ABS:
> + if (joydev->absmap[code] == 0) {
> + ev->type = JS_EVENT_BUTTON;
> + ev->number = 0;
> + if (joydev_correct(value, joydev->corr) >= 16384)
> + ev->value = 1;
> + else
> + ev->value = 0;
> + } else return 0;
> + break;
> + default:
> + return 0;
> + }
> + return 1;
> +}
> +
> static void joydev_event(struct input_handle *handle, unsigned int type, unsigned int code, int value)
> {
> struct joydev *joydev = handle->private;
> struct joydev_list *list = joydev->list;
> struct js_event event;
>
> - switch (type) {
> + if (joydev->digital) {
> + if (joydev_digital_event(&event,handle,type,code,value) == 0)
> + return;
> + } else switch (type) {
>
> case EV_KEY:
> if (code < BTN_MISC || value == 2) return;
> @@ -382,6 +443,8 @@
> joydev->absmap[joydev->abspam[i]] = i;
> }
> return 0;
> + case JSIOCSDIGITAL:
> + return get_user(joydev->digital, (__u8 *)arg);
> case JSIOCGAXMAP:
> return copy_to_user((__u8 *) arg, joydev->abspam,
> sizeof(__u8) * ABS_MAX) ? -EFAULT : 0;
> @@ -450,6 +513,7 @@
> joydev->handle.private = joydev;
>
> joydev->exist = 1;
> + joydev->digital = digital;
>
> for (i = 0; i < ABS_MAX; i++)
> if (test_bit(i, dev->absbit)) {
>
> /* snip */
>
> Patch for include/linux/joystick.h:
>
> /* snip */
>
> --- ../linux-2.4.31/include/linux/joystick.h 2005-06-26 15:44:37.000000000 +0200
> +++ include/linux/joystick.h 2005-07-06 22:37:36.000000000 +0200
> @@ -70,6 +70,7 @@
> #define JSIOCGAXMAP _IOR('j', 0x32, __u8[ABS_MAX]) /* get axis mapping */
> #define JSIOCSBTNMAP _IOW('j', 0x33, __u16[KEY_MAX - BTN_MISC]) /* set button mapping */
> #define JSIOCGBTNMAP _IOR('j', 0x34, __u16[KEY_MAX - BTN_MISC]) /* get button mapping */
> +#define JSIOCSDIGITAL _IOW('j', 0x35, __u8) /* set digital/analog flag */
>
> /*
> * Types and constants for get/set correction
>
> /* snip */
>
> Finally, a figure explaining the required connections to be made to
> connect a digital joystick to an analog input (xfig required):
>
> /* snip */
> #FIG 3.2 Produced by xfig version 3.2.5-alpha5
> Landscape
> Center
> Metric
> A4
> 70.00
> Single
> -2
> 1200 2
> 6 2250 4050 4275 4500
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 2250 4275 2700 4275
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 5
> 2700 4500 2700 4050 3825 4050 3825 4500 2700 4500
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 3825 4275 4275 4275
> -6
> 6 4050 4050 6075 4500
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 4050 4275 4500 4275
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 5
> 4500 4500 4500 4050 5625 4050 5625 4500 4500 4500
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 5625 4275 6075 4275
> -6
> 6 6075 4050 8100 4500
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 6075 4275 6525 4275
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 5
> 6525 4500 6525 4050 7650 4050 7650 4500 6525 4500
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 7650 4275 8100 4275
> -6
> 6 6075 2250 8100 2700
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 6075 2475 6525 2475
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 5
> 6525 2700 6525 2250 7650 2250 7650 2700 6525 2700
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 7650 2475 8100 2475
> -6
> 6 6075 8550 8100 9000
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 6075 8775 6525 8775
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 5
> 6525 9000 6525 8550 7650 8550 7650 9000 6525 9000
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 7650 8775 8100 8775
> -6
> 6 6075 6750 8100 7200
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 6075 6975 6525 6975
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 5
> 6525 7200 6525 6750 7650 6750 7650 7200 6525 7200
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 7650 6975 8100 6975
> -6
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 1125 3825 225 225 1125 3825 1350 3825
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 1125 4725 225 225 1125 4725 1350 4725
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 1125 5625 225 225 1125 5625 1350 5625
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 1125 6525 225 225 1125 6525 1350 6525
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 1125 7425 225 225 1125 7425 1350 7425
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 2025 4275 225 225 2025 4275 2250 4275
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 2025 5175 225 225 2025 5175 2250 5175
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 2025 6075 225 225 2025 6075 2250 6075
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 2025 6975 225 225 2025 6975 2250 6975
> 1 3 0 1 0 0 50 0 20 0.000 1 0.0000 6075 4275 75 75 6075 4275 6150 4275
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 9900 4275 225 225 9900 4275 10125 4275
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 9900 3375 225 225 9900 3375 10125 3375
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 9900 2475 225 225 9900 2475 10125 2475
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 9900 5175 225 225 9900 5175 10125 5175
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 9900 6075 225 225 9900 6075 10125 6075
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 9900 6975 225 225 9900 6975 10125 6975
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 9900 7875 225 225 9900 7875 10125 7875
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 9900 8775 225 225 9900 8775 10125 8775
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 10800 2925 225 225 10800 2925 11025 2925
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 10800 3825 225 225 10800 3825 11025 3825
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 10800 4725 225 225 10800 4725 11025 4725
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 10800 5625 225 225 10800 5625 11025 5625
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 10800 6525 225 225 10800 6525 11025 6525
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 10800 7425 225 225 10800 7425 11025 7425
> 1 3 0 1 0 7 50 0 -1 0.000 1 0.0000 10800 8325 225 225 10800 8325 11025 8325
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 8100 4275 9675 4275
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 6075 2475 6075 4275
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 8100 2475 9675 2475
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 8100 6975 9675 6975
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 8100 8775 9675 8775
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 6075 6975 6075 8775
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 2
> 1350 3825 10575 3825
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 4
> 9675 7875 3600 7875 3600 6525 1350 6525
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 4
> 1350 5625 4050 5625 4050 7425 10575 7425
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 4
> 1350 4725 8550 4725 8550 3375 9675 3375
> 2 1 0 1 0 7 50 0 -1 0.000 0 0 -1 0 0 4
> 2250 6075 6075 6075 6075 5175 9675 5175
> 4 0 0 50 0 0 24 0.0000 4 270 210 675 3825 1\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 675 4725 2\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 675 5625 3\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 675 6525 4\001
> 4 0 0 50 0 0 24 0.0000 4 285 210 675 7425 5\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 1575 4275 6\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 1575 5175 7\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 1575 6075 8\001
> 4 0 0 50 0 0 24 0.0000 4 285 210 1575 6975 9\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 10125 2475 1\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 10125 3375 2\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 10125 4275 3\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 10125 5175 4\001
> 4 0 0 50 0 0 24 0.0000 4 285 210 10125 6075 5\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 10125 6975 6\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 10125 7875 7\001
> 4 0 0 50 0 0 24 0.0000 4 270 210 10125 8775 8\001
> 4 0 0 50 0 0 24 0.0000 4 285 210 11025 2925 9\001
> 4 0 0 50 0 0 24 0.0000 4 270 420 11025 3825 10\001
> 4 0 0 50 0 0 24 0.0000 4 270 420 11025 4725 11\001
> 4 0 0 50 0 0 24 0.0000 4 270 420 11025 5625 12\001
> 4 0 0 50 0 0 24 0.0000 4 270 420 11025 6525 13\001
> 4 0 0 50 0 0 24 0.0000 4 270 420 11025 7425 14\001
> 4 0 0 50 0 0 24 0.0000 4 285 420 11025 8325 15\001
> 4 0 0 50 0 0 36 0.0000 4 540 2865 9225 1800 PC Joystick\001
> 4 0 0 50 0 0 36 0.0000 4 540 3360 450 1800 Atari Joystick\001
> 4 0 0 50 0 0 48 0.0000 4 720 9945 1800 900 "El Cheapo" Joystick Interface\001
> 4 0 0 50 0 0 24 0.0000 4 270 2025 10575 9450 2003 THOR\001
> 4 0 0 50 0 32 36 0.0000 4 420 465 5220 8730 W\001
> 4 0 0 50 0 0 36 0.0000 4 420 4110 1170 8730 All resistors 22K\001
> /* snip */
>
>

--
Vojtech Pavlik
SuSE Labs, SuSE CR
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