diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-mpc.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-mpc.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c index af349661fd76..8de8296d2583 100644 --- a/drivers/i2c/busses/i2c-mpc.c +++ b/drivers/i2c/busses/i2c-mpc.c @@ -105,23 +105,30 @@ static irqreturn_t mpc_i2c_isr(int irq, void *dev_id) /* Sometimes 9th clock pulse isn't generated, and slave doesn't release * the bus, because it wants to send ACK. * Following sequence of enabling/disabling and sending start/stop generates - * the 9 pulses, so it's all OK. + * the 9 pulses, each with a START then ending with STOP, so it's all OK. */ static void mpc_i2c_fixup(struct mpc_i2c *i2c) { int k; - u32 delay_val = 1000000 / i2c->real_clk + 1; - - if (delay_val < 2) - delay_val = 2; + unsigned long flags; for (k = 9; k; k--) { writeccr(i2c, 0); - writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN); + writeb(0, i2c->base + MPC_I2C_SR); /* clear any status bits */ + writeccr(i2c, CCR_MEN | CCR_MSTA); /* START */ + readb(i2c->base + MPC_I2C_DR); /* init xfer */ + udelay(15); /* let it hit the bus */ + local_irq_save(flags); /* should not be delayed further */ + writeccr(i2c, CCR_MEN | CCR_MSTA | CCR_RSTA); /* delay SDA */ readb(i2c->base + MPC_I2C_DR); - writeccr(i2c, CCR_MEN); - udelay(delay_val << 1); + if (k != 1) + udelay(5); + local_irq_restore(flags); } + writeccr(i2c, CCR_MEN); /* Initiate STOP */ + readb(i2c->base + MPC_I2C_DR); + udelay(15); /* Let STOP propagate */ + writeccr(i2c, 0); } static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing) |