I think we also need extra patch for fixing stability issue.
Sometimes after back from retention/off mode, OMAP3430 I2C controller
stops working even all register settings are restored.
OMAP3430 TRM says: "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."
diff --git a/drivers/i2c/busses/i2c-omap.c
b/drivers/i2c/busses/i2c-omap.c index 5ce055c..b084209 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -238,12 +238,14 @@ 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;
omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
-----Original Message-----
From: linux-omap-owner@xxxxxxxxxxxxxxx
[mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of Kevin Hilman
Sent: Friday, June 26, 2009 10:19 PM
To: Aaro Koskinen
Cc: linux-omap@xxxxxxxxxxxxxxx; Rajendra Nayak; Hogander Jouni
(Nokia-D/Tampere); Jagadeesh Bhaskar Pakaravoor
Subject: Re: [PATCH 4/4] I2C: OMAP3: PM: (re)init for every transfer to
support off-mode
Aaro Koskinen <aaro.koskinen@xxxxxxxxx> writes:
> Kevin Hilman wrote:
>> From: Rajendra Nayak <rnayak@xxxxxx>
>>
>> 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.)
>>
>> Signed-off-by: Jouni Hogander <jouni.hogander@xxxxxxxxx>
>> Signed-off-by: Rajendra Nayak <rnayak@xxxxxx>
>> Cc: Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@xxxxxx>
>> Cc: Aaro Koskinen <aaro.koskinen@xxxxxxxxx>
>> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
>
> This patch introduces a compiler warning:
>
> CC drivers/i2c/busses/i2c-omap.o
> drivers/i2c/busses/i2c-omap.c: In function 'omap_i2c_init':
> drivers/i2c/busses/i2c-omap.c:303: warning: unused variable 'v'
>
> So the declaration of "v" should be also removed here:
>
Thanks, updated patch in my queue an below for reference.
Kevin
>From 6880534c0a42beea0e500a566f910875342c313b Mon Sep 17 00:00:00 2001
From: Rajendra Nayak <rnayak@xxxxxx>
Date: Fri, 26 Sep 2008 17:48:07 +0530
Subject: [PATCH] I2C: 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.)
Signed-off-by: Jouni Hogander <jouni.hogander@xxxxxxxxx>
Signed-off-by: Rajendra Nayak <rnayak@xxxxxx>
Cc: Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@xxxxxx>
Cc: Aaro Koskinen <aaro.koskinen@xxxxxxxxx>
Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-omap.c | 62
+++++++++++++++++++++++++---------------
1 files changed, 39 insertions(+), 23 deletions(-)
diff --git a/drivers/i2c/busses/i2c-omap.c
b/drivers/i2c/busses/i2c-omap.c index ece0125..6b28e8a 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 +236,16 @@ 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_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);
+ }
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 +271,7 @@
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 +300,22 @@ 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); @@ -373,23 +384,28
@@ 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;
}
--
1.6.3.2
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