I2C pxa fast mode (400khz) support

Add fast_mode option to i2c_pxa_platform_data and use it to set the ICR_FM bit appropriately when i2c_pxa_reset is called. Parameter called fast_mode rather than frequency as this driver is also used for the i2c_pxa_pwr bus which has different normal and fast frequencies.

Signed-off-by Jonathan Cameron <jic23-KWPb1pKIrIJaa/[email protected]>

---
 drivers/i2c/busses/i2c-pxa.c        |    4 +++-
 include/asm-arm/arch-pxa/i2c.h      |    1 +
 include/asm-arm/arch-pxa/pxa-regs.h |    1 +
 3 files changed, 5 insertions(+), 1 deletion(-)

include/asm-arm/arch-pxa/pxa-regs.h +1 -0

@@ -448,6 +448,7 @@
 #define ICR_ALDIE	(1 << 12)	   /* enable arbitration interrupt */
 #define ICR_SADIE	(1 << 13)	   /* slave address detected int enable */
 #define ICR_UR		(1 << 14)	   /* unit reset */
+#define ICR_FM		(1 << 15)	   /* fast mode */
 
 #define ISR_RWM		(1 << 0)	   /* read/write mode */
 #define ISR_ACKNAK	(1 << 1)	   /* ack/nak status */

include/asm-arm/arch-pxa/i2c.h +1 -0

@@ -66,6 +66,7 @@ struct i2c_pxa_platform_data {
 	struct i2c_slave_client	*slave;
 	unsigned int		class;
 	int			use_pio;
+	int			fast_mode;
 };
 
 extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);

drivers/i2c/busses/i2c-pxa.c +3 -1

@@ -67,6 +67,7 @@ struct pxa_i2c {
 
 	int			irq;
 	int			use_pio;
+	int			fast_mode;
 };
 
 #define _IBMR(i2c)	((i2c)->reg_base + 0)

@@ -365,7 +366,7 @@ static void i2c_pxa_reset(struct pxa_i2c
 	writel(i2c->slave_addr, _ISAR(i2c));
 
 	/* set control register values */
-	writel(I2C_ICR_INIT, _ICR(i2c));
+	writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
 
 #ifdef CONFIG_I2C_PXA_SLAVE
 	dev_info(&i2c->adap.dev, "Enabling slave mode\n");

@@ -1041,6 +1042,7 @@ static int i2c_pxa_probe(struct platform
 	if (plat) {
 		i2c->adap.class = plat->class;
 		i2c->use_pio = plat->use_pio;
+		i2c->fast_mode = plat->fast_mode;
 	}
 
 	if (i2c->use_pio) {

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Quoted 4 lines · Jonathan Cameron

Add fast_mode option to i2c_pxa_platform_data and use it to set the ICR_FM bit appropriately when i2c_pxa_reset is called. Parameter called fast_mode rather than frequency as this driver is also used for the i2c_pxa_pwr bus which has different normal and fast frequencies.

Maybe we should convert that (as well as 'use_pio') to a bit field to save another byte.

Otherwise looks OK to me.

Quoted 58 lines

Signed-off-by Jonathan Cameron <[email protected]>

---
 drivers/i2c/busses/i2c-pxa.c        |    4 +++-
 include/asm-arm/arch-pxa/i2c.h      |    1 +
 include/asm-arm/arch-pxa/pxa-regs.h |    1 +
 3 files changed, 5 insertions(+), 1 deletion(-)

include/asm-arm/arch-pxa/pxa-regs.h +1 -0

@@ -448,6 +448,7 @@
 #define ICR_ALDIE	(1 << 12)	   /* enable arbitration interrupt */
 #define ICR_SADIE	(1 << 13)	   /* slave address detected int enable */
 #define ICR_UR		(1 << 14)	   /* unit reset */
+#define ICR_FM		(1 << 15)	   /* fast mode */
 
 #define ISR_RWM		(1 << 0)	   /* read/write mode */
 #define ISR_ACKNAK	(1 << 1)	   /* ack/nak status */

include/asm-arm/arch-pxa/i2c.h +1 -0

@@ -66,6 +66,7 @@ struct i2c_pxa_platform_data {
 	struct i2c_slave_client	*slave;
 	unsigned int		class;
 	int			use_pio;
+	int			fast_mode;
 };
 
 extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);

drivers/i2c/busses/i2c-pxa.c +3 -1

@@ -67,6 +67,7 @@ struct pxa_i2c {
 
 	int			irq;
 	int			use_pio;
+	int			fast_mode;
 };
 
 #define _IBMR(i2c)	((i2c)->reg_base + 0)

@@ -365,7 +366,7 @@ static void i2c_pxa_reset(struct pxa_i2c
 	writel(i2c->slave_addr, _ISAR(i2c));
 
 	/* set control register values */
-	writel(I2C_ICR_INIT, _ICR(i2c));
+	writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
 
 #ifdef CONFIG_I2C_PXA_SLAVE
 	dev_info(&i2c->adap.dev, "Enabling slave mode\n");

@@ -1041,6 +1042,7 @@ static int i2c_pxa_probe(struct platform
 	if (plat) {
 		i2c->adap.class = plat->class;
 		i2c->use_pio = plat->use_pio;
+		i2c->fast_mode = plat->fast_mode;
 	}
 
 	if (i2c->use_pio) {

Quoted 4 lines

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http://lists.lm-sensors.org/mailman/listinfo/i2c

Quoted 8 lines · Eric Miao

Quoted 4 lines · Jonathan Cameron

Add fast_mode option to i2c_pxa_platform_data and use it to set the ICR_FM bit appropriately when i2c_pxa_reset is called. Parameter called fast_mode rather than frequency as this driver is also used for the i2c_pxa_pwr bus which has different normal and fast frequencies.

Maybe we should convert that (as well as 'use_pio') to a bit field to save another byte.

I think use_pio and fast_mode could both be bits.

Quoted 6 lines · Ben Dooks

Quoted 5 lines · Eric Miao

Quoted 4 lines · Jonathan Cameron

Add fast_mode option to i2c_pxa_platform_data and use it to set the ICR_FM bit appropriately when i2c_pxa_reset is called. Parameter called fast_mode rather than frequency as this driver is also used for the i2c_pxa_pwr bus which has different normal and fast frequencies.

Quoted 3 lines

Quoted 2 lines

Maybe we should convert that (as well as 'use_pio') to a bit field to save another byte.

I think use_pio and fast_mode could both be bits.

Or alternatively, "bool" ... which is usually a byte, and on ARM will let GCC eliminate a comparision instruction. Just load byte and branch on zero/nonzero, vs needing one more instruction.

Quoted 6 lines

Quoted 1 line

I think use_pio and fast_mode could both be bits.

Or alternatively, "bool" ... which is usually a byte, and on ARM will let GCC eliminate a comparision instruction. Just load byte and branch on zero/nonzero, vs needing one more instruction.

Unfortunately, on ARM the LDR/LDRB instructions can not update the condition codes.

Add fast_mode option to i2c_pxa_platform_data and use it to set the ICR_FM bit appropriately when i2c_pxa_reset is called. Parameter called fast_mode rather than frequency as this driver is also used for the i2c_pxa_pwr bus which has different normal and fast frequencies.

Signed-off-by Jonathan Cameron <jic23-KWPb1pKIrIJaa/[email protected]>

---
 drivers/i2c/busses/i2c-pxa.c        |    4 +++-
 include/asm-arm/arch-pxa/i2c.h      |    1 +
 include/asm-arm/arch-pxa/pxa-regs.h |    1 +
 3 files changed, 5 insertions(+), 1 deletion(-)

include/asm-arm/arch-pxa/pxa-regs.h +1 -0

@@ -448,6 +448,7 @@
 #define ICR_ALDIE	(1 << 12)	   /* enable arbitration interrupt */
 #define ICR_SADIE	(1 << 13)	   /* slave address detected int enable */
 #define ICR_UR		(1 << 14)	   /* unit reset */
+#define ICR_FM		(1 << 15)	   /* fast mode */
 
 #define ISR_RWM		(1 << 0)	   /* read/write mode */
 #define ISR_ACKNAK	(1 << 1)	   /* ack/nak status */

include/asm-arm/arch-pxa/i2c.h +1 -0

@@ -66,6 +66,7 @@ struct i2c_pxa_platform_data {
 	struct i2c_slave_client	*slave;
 	unsigned int		class;
 	int			use_pio;
+	int			fast_mode;
 };
 
 extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);

drivers/i2c/busses/i2c-pxa.c +2 -1

@@ -67,6 +67,7 @@ struct pxa_i2c {
 
 	int			irq;
 	int			use_pio;
+	int			fast_mode;
 };
 
 #define _IBMR(i2c)	((i2c)->reg_base + 0)

@@ -365,7 +366,7 @@ static void i2c_pxa_reset(struct pxa_i2c
 	writel(i2c->slave_addr, _ISAR(i2c));
 
 	/* set control register values */
-	writel(I2C_ICR_INIT, _ICR(i2c));
+	writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
 
 #ifdef CONFIG_I2C_PXA_SLAVE
 	dev_info(&i2c->adap.dev, "Enabling slave mode\n");

Add fast_mode option to i2c_pxa_platform_data and use it to set the ICR_FM bit appropriately when i2c_pxa_reset is called. Parameter called fast_mode rather than frequency as this driver is also used for the i2c_pxa_pwr bus which has different normal and fast frequencies.

Signed-off-by Jonathan Cameron <[email protected]>

Quoted 5 lines · Jonathan Cameron

Add fast_mode option to i2c_pxa_platform_data and use it to set the ICR_FM bit appropriately when i2c_pxa_reset is called. Parameter called fast_mode rather than frequency as this driver is also used for the i2c_pxa_pwr bus which has different normal and fast frequencies.

Quoted 1 line

Signed-off-by Jonathan Cameron <jic23-KWPb1pKIrIJaa/[email protected]>

Unfortuantely due to the problem of all the registers in one place, this really will need to be applied by RMK. However due to the current amount of work in the PXA tree, and the number of patches he is carrying for merging this is going to be too late for this kernel merge.

Quoted 6 lines · Ben Dooks

Quoted 5 lines · Jonathan Cameron

Add fast_mode option to i2c_pxa_platform_data and use it to set the ICR_FM bit appropriately when i2c_pxa_reset is called. Parameter called fast_mode rather than frequency as this driver is also used for the i2c_pxa_pwr bus which has different normal and fast frequencies.

Quoted 7 lines

Quoted 1 line

Signed-off-by Jonathan Cameron <[email protected]>

Unfortuantely due to the problem of all the registers in one place, this really will need to be applied by RMK. However due to the current amount of work in the PXA tree, and the number of patches he is carrying for merging this is going to be too late for this kernel merge.

Actually, this round of separation work of the pxa-regs.h has been done several weeks ago, so I don't see this patch is likely to cause any merge conflict.

But Russell is going to freeze the pxa branch, I see little chance this be fixed quickly and get into :(

Quoted 15 lines · eric miao

Quoted 6 lines · Ben Dooks

Quoted 5 lines · Jonathan Cameron

Add fast_mode option to i2c_pxa_platform_data and use it to set the ICR_FM bit appropriately when i2c_pxa_reset is called. Parameter called fast_mode rather than frequency as this driver is also used for the i2c_pxa_pwr bus which has different normal and fast frequencies.

Quoted 7 lines

Quoted 1 line

Signed-off-by Jonathan Cameron <[email protected]>

Unfortuantely due to the problem of all the registers in one place, this really will need to be applied by RMK. However due to the current amount of work in the PXA tree, and the number of patches he is carrying for merging this is going to be too late for this kernel merge.

Quoted 7 lines

Actually, this round of separation work of the pxa-regs.h has been done several weeks ago, so I don't see this patch is likely to cause any merge conflict.

But Russell is going to freeze the pxa branch, I see little chance this be fixed quickly and get into :(

Dear all, thanks for the comments.

I'll switch the use_pio and fast_mode flags to bit fields and resend when next kernel merge begins.

As I'm maintaining rather a lot of platform specific stuff anyway for my use, one more won't do any harm for a few weeks!

I think most of RMK's pxa tree has been merged, so a diff against a current -git release should give you a better starting point.

Quoted 3 lines · Ben Dooks

I think most of RMK's pxa tree has been merged, so a diff against a current -git release should give you a better starting point.

There's still around 300K of PXA stuff outstanding - but unfortunately I can't update the 'nightly' snapshots with the outstanding commits because I can't get a reasonable patch out of git:

$ git-diff -u master...pxa |less

MAINTAINERS +6 -0

diff --cc MAINTAINERS
index 1528e58,8f0ec46,c68a118..20aef95
@@@@ -481,11 -475,11 -475,11 +475,28 @@@@ M:    [email protected]
   L:   [email protected] (subscribers-only)
   S:   Maintained
 
+++ARM/COMPULAB CM-X270/EM-X270 MACHINE SUPPORT
+++P:   Mike Rapoport
+++M:   [email protected]
+++L:   [email protected] (subscribers-only)
+++S:   Maintained
+++

This is basically because 'master...pxa' has multiple common ancestors.

Hm, I don't see that with your current tree:

	ukleinek@zentaur:~/gsrc/linux-2.6$ git merge-base --all rmk/pxa rmk/master
	543cf4cb3fe6f6cae3651ba918b9c56200b257d0