/* Program the BRG to the given sampling rate and multiplier
*
* @brg: the BRG, QE_BRG1 - QE_BRG16
* @rate: the desired sampling rate
* @multiplier: corresponds to the value programmed in GUMR_L[RDCR] or
* GUMR_L[TDCR]. E.g., if this BRG is the RX clock, and GUMR_L[RDCR]=01,
* then 'multiplier' should be 8.
*/
int qe_setbrg(enum qe_clock brg, unsigned int rate, unsigned int multiplier)
{
u32 divisor, tempval;
u32 div16 = 0;
if ((brg < QE_BRG1) || (brg > QE_BRG16))
return -EINVAL;
divisor = get_brg_clk() / (rate * multiplier);
if (divisor > QE_BRGC_DIVISOR_MAX + 1) {
div16 = QE_BRGC_DIV16;
divisor /= 16;
}
/* Errata QE_General4, which affects some MPC832x and MPC836x SOCs, says
that the BRG divisor must be even if you're not using divide-by-16
mode. */
if (!div16 && (divisor & 1))
divisor++;
tempval = ((divisor - 1) << QE_BRGC_DIVISOR_SHIFT) |
QE_BRGC_ENABLE | div16;
out_be32(&qe_immr->brg.brgc[brg - QE_BRG1], tempval);
return 0;
}
/* This function is used by UARTS, or anything else that uses a 16x
* oversampled clock.
*/
void qe_setbrg(u32 brg, u32 rate)
{
volatile u32 *bp;
u32 divisor, tempval;
int div16 = 0;
bp = &qe_immr->brg.brgc[brg];
divisor = (get_brg_clk() / rate);
if (divisor > QE_BRGC_DIVISOR_MAX + 1) {
div16 = 1;
divisor /= 16;
}
tempval = ((divisor - 1) << QE_BRGC_DIVISOR_SHIFT) | QE_BRGC_ENABLE;
if (div16)
tempval |= QE_BRGC_DIV16;
out_be32(bp, tempval);
}
