long
gpioread(Chan *c, void *va, long n, vlong off)
{
int type, scheme;
uint pin;
char *a;
a = va;
if(c->qid.type & QTDIR)
{
return devdirread(c, va, n, 0, 0, gpiogen);
}
type = FILE_TYPE(c->qid);
scheme = SCHEME_TYPE(c->qid);
if(scheme != Qgeneric && scheme != pinscheme)
{
error(nil);
}
switch(type)
{
case Qdata:
pin = PIN_NUMBER(c->qid);
a[0] = (gpioin(pin))?'1':'0';
n = 1;
break;
case Qctl:
break;
case Qevent:
if(off >= 4)
{
off %= 4;
eventvalue = 0;
}
sleep(&rend, isset, 0);
if(off + n > 4)
{
n = 4 - off;
}
memmove(a, &eventvalue + off, n);
}
return n;
}
static void adm_read(int cs, char *buf, unsigned int bits)
{
int i, len = (bits + 7) / 8;
__u8 mask;
gpioout(eecs, (cs ? eecs : 0));
udelay(EECK_EDGE_TIME);
/* Byte assemble from MSB to LSB */
for (i = 0; i < len; i++) {
__u8 byte;
/* Bit bang from MSB to LSB */
for (mask = 0x80, byte = 0; mask && bits > 0; mask >>= 1, bits --) {
__u8 gp;
/* Clock low */
gpioout(eesk, 0);
udelay(EECK_EDGE_TIME);
/* Input on rising edge */
gp = gpioin();
if (gp & eedi)
byte |= mask;
/* Clock high */
gpioout(eesk, eesk);
udelay(EECK_EDGE_TIME);
}
*buf++ = byte;
}
/* Clock low */
gpioout(eesk, 0);
udelay(EECK_EDGE_TIME);
if (cs)
gpioout(eecs, 0);
}