On Thu, Dec 17, 2009 at 08:36:30 +0530, Menon, Nishanth wrote:
> Alexander Shishkin said the following on 12/16/2009 07:32 PM:
> >This is to avoid insanely long lines and levels of indentation.
> >
> >Signed-off-by: Alexander Shishkin <virtuoso@xxxxxxxxx>
> >CC: linux-i2c@xxxxxxxxxxxxxxx
> >CC: linux-omap@xxxxxxxxxxxxxxx
> >---
> > drivers/i2c/busses/i2c-omap.c | 43 ++++++++++++++++++++++------------------
> > 1 files changed, 24 insertions(+), 19 deletions(-)
> >
> >diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> >index 75bf3ad..ad8242a 100644
> >--- a/drivers/i2c/busses/i2c-omap.c
> >+++ b/drivers/i2c/busses/i2c-omap.c
> >@@ -671,6 +671,27 @@ omap_i2c_rev1_isr(int this_irq, void *dev_id)
> > #define omap_i2c_rev1_isr NULL
> > #endif
> >+/*
> >+ * 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.
> >+ */
> >+static int omap3430_workaround(struct omap_i2c_dev *dev, u16 *stat, int *err)
>
> note, though this is identified as being part of 3430, it is not
> really restricted to 3430 alone
> we might want to rename this as errata_omap3_1p153() perhaps?
Ok, I don't see why not.
> >+{
> >+ 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;
> >+ return -1;
> >+ }
> >+ cpu_relax();
> >+ *stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
> >+ }
> >+
> >+ return 0;
> >+}
> wonder if using an inline might help throw away the function call
> overhead (considering it is used only once)?
objdump -S says it's implicitly inlined already. I actually had in mind
the conversation about generalizing the features/erratas for chips/IPs
and that somehow stopped me from explicitly inlining this. Do you think
it makes sense (for the next version of this patchset) to explicitly
inline this?
> >+
> > static irqreturn_t
> > omap_i2c_isr(int this_irq, void *dev_id)
> > {
> >@@ -794,25 +815,9 @@ complete:
> > 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 (dev->rev <= OMAP_I2C_REV_ON_3430) {
> >- 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);
> >- }
> >- }
> >+ if (dev->rev <= OMAP_I2C_REV_ON_3430 &&
> >+ omap3430_workaround(dev, &stat, &err))
> >+ goto complete;
> > omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
> > }
>
> Regards,
> Nishanth Menon
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