Commit ef871432 authored by Rajendra Nayak's avatar Rajendra Nayak Committed by Ben Dooks
Browse files

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: default avatarJouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: default avatarRajendra 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: default avatarKevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent 6d1ea0f6

drivers/i2c/busses/i2c-omap.c

+41 −23
Original line number Diff line number Diff line
@@ -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,
@@ -230,8 +236,17 @@ 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);

}
@@ -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;

}

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