From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH] I2C: OMAP3: PM: (re)init for every transfer to support off-mode Date: Mon, 03 Aug 2009 15:11:48 -0700 Message-ID: <4A7760A4.3080109@deeprootsystems.com> References: <1248217743-24330-1-git-send-email-khilman@deeprootsystems.com> <20090729234308.GA8850@fluff.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090729234308.GA8850-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ben Dooks Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org Ben Dooks wrote: > On Tue, Jul 21, 2009 at 04:09:03PM -0700, Kevin Hilman wrote: >> From: Rajendra Nayak >> >> 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? next merge window is fine. Thanks, Kevin >> Signed-off-by: Jouni Hogander >> Signed-off-by: Rajendra Nayak >> Cc: Jagadeesh Bhaskar Pakaravoor >> Cc: Aaro Koskinen >> Cc: Jon Hunter >> Cc: Hu Tao >> Cc: Xiaolong Chen >> Signed-off-by: Kevin Hilman >> --- >> 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 majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >