From: Ben Dooks <ben-linux@fluff.org>
To: Kevin Hilman <khilman@deeprootsystems.com>
Cc: ben-linux@fluff.org, linux-i2c@vger.kernel.org,
linux-omap@vger.kernel.org
Subject: Re: [PATCH] I2C: OMAP3: PM: (re)init for every transfer to support off-mode
Date: Thu, 30 Jul 2009 00:43:08 +0100 [thread overview]
Message-ID: <20090729234308.GA8850@fluff.org.uk> (raw)
In-Reply-To: <1248217743-24330-1-git-send-email-khilman@deeprootsystems.com>
On Tue, Jul 21, 2009 at 04:09:03PM -0700, Kevin Hilman wrote:
> From: Rajendra Nayak <rnayak@ti.com>
>
> 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 <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>
> ---
> 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
>
> --
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--
Ben (ben@fluff.org, http://www.fluff.org/)
'a smiley only costs 4 bytes'
next prev parent reply other threads:[~2009-07-29 23:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-21 23:09 [PATCH] I2C: OMAP3: PM: (re)init for every transfer to support off-mode Kevin Hilman
2009-07-29 23:43 ` Ben Dooks [this message]
[not found] ` <20090729234308.GA8850-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org>
2009-08-03 22:11 ` Kevin Hilman
2009-09-30 22:06 ` Kevin Hilman
[not found] ` <636c5030909301506p7da5f016m5148ce6cd279e704-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-11-12 19:29 ` Kevin Hilman
2009-11-23 16:59 Kevin Hilman
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