From: Kevin Hilman <khilman@deeprootsystems.com>
To: Ben Dooks <ben-linux@fluff.org>
Cc: 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: Wed, 30 Sep 2009 15:06:09 -0700 [thread overview]
Message-ID: <636c5030909301506p7da5f016m5148ce6cd279e704@mail.gmail.com> (raw)
In-Reply-To: <4A7760A4.3080109@deeprootsystems.com>
On Mon, Aug 3, 2009 at 3:11 PM, Kevin Hilman
<khilman@deeprootsystems.com> wrote:
> Ben Dooks wrote:
>>
>> 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?
>
> next merge window is fine.
>
Ben,
It doesn't look like this made it in during the 2.6.32 merge window.
Can you queue it for the -rc series?
Kevin
>>> 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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>>
>
>
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next prev parent reply other threads:[~2009-09-30 22:06 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
[not found] ` <20090729234308.GA8850-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org>
2009-08-03 22:11 ` Kevin Hilman
2009-09-30 22:06 ` Kevin Hilman [this message]
[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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