From: Rajendra Nayak <rnayak@xxxxxx> 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. Signed-off-by: Jouni Hogander <jouni.hogander@xxxxxxxxx> Signed-off-by: Rajendra Nayak <rnayak@xxxxxx> Cc: Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@xxxxxx> Cc: Aaro Koskinen <aaro.koskinen@xxxxxxxxx> Cc: Jon Hunter <jon-hunter@xxxxxx> Cc: Hu Tao <taohu@xxxxxxxxxxxx> Cc: Xiaolong Chen <A21785@xxxxxxxxxxxx> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> --- Originally posted on 21-july-2009 for the 2.6.32 merge window: http://marc.info/?l=linux-i2c&m=124821776627177&w=2 Please queue for 2.6.32-rc if still possible, or at least for 2.6.33. 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 827da08..75bf3ad 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; } -- 1.6.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
