On Tue, Jul 21, 2009 at 04:09:03PM -0700, Kevin Hilman wrote: > From: Rajendra Nayak <[email protected]> > > Because of OMAP off-mode, powerdomain can go off when I2C is idle. > Save enough state, and do a re-init for each transfer. > > Additional save/restore state added by Jagadeesh Bhaskar Pakaravoor > (SYSC_REG) and Aaro Koskinen (wakeup sources.) > > Also, The OMAP3430 TRM states: > > "During active mode (I2Ci.I2C_CON[15] I2C_EN bit is set to 1), make no > changes to the I2Ci.I2C_SCLL and I2Ci.I2C_SCLH registers. Changes may > result in unpredictable behavior." > > Hence, the I2C_EN bit should be clearer when modifying these > registers. Please note that clearing the entire I2C_CON register to > disable the I2C module is safe, because the I2C_CON register is > re-configured for each transfer.
should this be applied as a bugfix, or kept for next merge window? > Signed-off-by: Jouni Hogander <[email protected]> > Signed-off-by: Rajendra Nayak <[email protected]> > Cc: Jagadeesh Bhaskar Pakaravoor <[email protected]> > Cc: Aaro Koskinen <[email protected]> > Cc: Jon Hunter <[email protected]> > Cc: Hu Tao <[email protected]> > Cc: Xiaolong Chen <[email protected]> > Signed-off-by: Kevin Hilman <[email protected]> > --- > This patch has been tested extensively as part of the OMAP 'PM branch' > > drivers/i2c/busses/i2c-omap.c | 64 ++++++++++++++++++++++++++-------------- > 1 files changed, 41 insertions(+), 23 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index ad8d201..bb8ae50 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -178,6 +178,12 @@ struct omap_i2c_dev { > unsigned b_hw:1; /* bad h/w fixes */ > unsigned idle:1; > u16 iestate; /* Saved interrupt register */ > + u16 pscstate; > + u16 scllstate; > + u16 sclhstate; > + u16 bufstate; > + u16 syscstate; > + u16 westate; > }; > > static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev, > @@ -230,9 +236,18 @@ static void omap_i2c_unidle(struct omap_i2c_dev *dev) > > clk_enable(dev->iclk); > clk_enable(dev->fclk); > + if (cpu_is_omap34xx()) { > + omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0); > + omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, dev->pscstate); > + omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, dev->scllstate); > + omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, dev->sclhstate); > + omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, dev->bufstate); > + omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, dev->syscstate); > + omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate); > + omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN); > + } > dev->idle = 0; > - if (dev->iestate) > - omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate); > + omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate); > } > > static void omap_i2c_idle(struct omap_i2c_dev *dev) > @@ -258,7 +273,7 @@ static void omap_i2c_idle(struct omap_i2c_dev *dev) > > static int omap_i2c_init(struct omap_i2c_dev *dev) > { > - u16 psc = 0, scll = 0, sclh = 0; > + u16 psc = 0, scll = 0, sclh = 0, buf = 0; > u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0; > unsigned long fclk_rate = 12000000; > unsigned long timeout; > @@ -287,24 +302,22 @@ static int omap_i2c_init(struct omap_i2c_dev *dev) > SYSC_AUTOIDLE_MASK); > > } else if (dev->rev >= OMAP_I2C_REV_ON_3430) { > - u32 v; > - > - v = SYSC_AUTOIDLE_MASK; > - v |= SYSC_ENAWAKEUP_MASK; > - v |= (SYSC_IDLEMODE_SMART << > + dev->syscstate = SYSC_AUTOIDLE_MASK; > + dev->syscstate |= SYSC_ENAWAKEUP_MASK; > + dev->syscstate |= (SYSC_IDLEMODE_SMART << > __ffs(SYSC_SIDLEMODE_MASK)); > - v |= (SYSC_CLOCKACTIVITY_FCLK << > + dev->syscstate |= (SYSC_CLOCKACTIVITY_FCLK << > __ffs(SYSC_CLOCKACTIVITY_MASK)); > > - omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, v); > + omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, > + dev->syscstate); > /* > * Enabling all wakup sources to stop I2C freezing on > * WFI instruction. > * REVISIT: Some wkup sources might not be needed. > */ > - omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, > - OMAP_I2C_WE_ALL); > - > + dev->westate = OMAP_I2C_WE_ALL; > + omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate); > } > } > omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0); > @@ -394,23 +407,28 @@ static int omap_i2c_init(struct omap_i2c_dev *dev) > omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll); > omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh); > > - if (dev->fifo_size) > - /* Note: setup required fifo size - 1 */ > - omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, > - (dev->fifo_size - 1) << 8 | /* RTRSH */ > - OMAP_I2C_BUF_RXFIF_CLR | > - (dev->fifo_size - 1) | /* XTRSH */ > - OMAP_I2C_BUF_TXFIF_CLR); > + if (dev->fifo_size) { > + /* Note: setup required fifo size - 1. RTRSH and XTRSH */ > + buf = (dev->fifo_size - 1) << 8 | OMAP_I2C_BUF_RXFIF_CLR | > + (dev->fifo_size - 1) | OMAP_I2C_BUF_TXFIF_CLR; > + omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf); > + } > > /* Take the I2C module out of reset: */ > omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN); > > /* Enable interrupts */ > - omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, > - (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY | > + dev->iestate = (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY | > OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK | > OMAP_I2C_IE_AL) | ((dev->fifo_size) ? > - (OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0)); > + (OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0); > + omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate); > + if (cpu_is_omap34xx()) { > + dev->pscstate = psc; > + dev->scllstate = scll; > + dev->sclhstate = sclh; > + dev->bufstate = buf; > + } > return 0; > } > > -- > 1.6.3.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Ben ([email protected], http://www.fluff.org/) 'a smiley only costs 4 bytes' -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
