From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Menon, Nishanth" Subject: Re: [PATCH 1/2] omap i2c: make errata 1.153 workaround a separate function Date: Thu, 17 Dec 2009 08:36:30 +0530 Message-ID: <4B29A036.2040807@ti.com> References: <1260972144-31593-1-git-send-email-virtuoso@slind.org> <1260972144-31593-2-git-send-email-virtuoso@slind.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1260972144-31593-2-git-send-email-virtuoso-0lOfPCoBze7YtjvyW6yDsg@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Alexander Shishkin Cc: "ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org" , "linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-i2c@vger.kernel.org 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 > CC: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > CC: linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > --- > 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? > +{ > + 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)? > + > 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