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i2c-omap: OMAP3: PM: (re)init for every transfer to support off-mode 

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@nokia.com>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Cc: Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@ti.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: Jon Hunter <jon-hunter@ti.com>
Cc: Hu Tao <taohu@motorola.com>
Cc: Xiaolong Chen <A21785@motorola.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Rajendra Nayak 2009-11-23 08:59:18 -08:00 committed by Ben Dooks
parent 6d1ea0f6af
commit ef871432e1
1 changed files with 41 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
drivers/i2c/busses/i2c-omap.c
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@ -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;
}