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i2c-omap: OMAP3430 Silicon Errata 1.153

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When an XRDY/XDR is hit, wait for XUDF before writing data to DATA_REG.
Otherwise some data bytes can be lost while transferring them from the
memory to the I2C interface.

Do a Busy-wait for XUDF, before writing data to DATA_REG. While waiting
if there is NACK | AL, set the appropriate error flags, ack the pending
interrupts and return from the ISR.

Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Vikram pandita <vikram.pandita@ti.com>
[ben-linux@fluff.org: fixed mail format and added i2c-omap to subject]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Sonasath, Moiz 2009-07-21 10:15:12 -05:00 • committed by Ben Dooks
parent 04c688dd7a
commit cd086d3aa6
1 changed files with 23 additions and 1 deletions
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24
drivers/i2c/busses/i2c-omap.c
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@ -672,9 +672,10 @@ omap_i2c_isr(int this_irq, void *dev_id)
break; break;
} }
err = 0;
complete:
omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat); omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
err = 0;
if (stat & OMAP_I2C_STAT_NACK) { if (stat & OMAP_I2C_STAT_NACK) {
err |= OMAP_I2C_STAT_NACK; err |= OMAP_I2C_STAT_NACK;
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
@ -764,6 +765,27 @@ omap_i2c_isr(int this_irq, void *dev_id)
"data to send\n"); "data to send\n");
break; break;
} }
/*
* OMAP3430 Errata 1.153: When an XRDY/XDR
* is hit, wait for XUDF before writing data
* to DATA_REG. Otherwise some data bytes can
* be lost while transferring them from the
* memory to the I2C interface.
*/
if (cpu_is_omap34xx()) {
while (!(stat & OMAP_I2C_STAT_XUDF)) {
if (stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
omap_i2c_ack_stat(dev, stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
err |= OMAP_I2C_STAT_XUDF;
goto complete;
}
cpu_relax();
stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
}
}
omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w); omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
} }
omap_i2c_ack_stat(dev, omap_i2c_ack_stat(dev,