* [PATCH v3] mfd: axp20x: Fix AXP806 access errors on cold boot
@ 2017-01-05 4:01 ` Chen-Yu Tsai
0 siblings, 0 replies; 4+ messages in thread
From: Chen-Yu Tsai @ 2017-01-05 4:01 UTC (permalink / raw)
To: Lee Jones
Cc: Chen-Yu Tsai, linux-kernel, linux-arm-kernel, linux-sunxi, Mark Brown
The AXP806 supports either master/standalone or slave mode.
Slave mode allows sharing the serial bus, even with multiple
AXP806 which all have the same hardware address.
This is done with extra "serial interface address extension",
or AXP806_BUS_ADDR_EXT, and "register address extension", or
AXP806_REG_ADDR_EXT, registers. The former is read-only, with
1 bit customizable at the factory, and 1 bit depending on the
state of an external pin. The latter is writable. Only when
the these device addressing bits (in the upper 4 bits of the
registers) match, will the device respond to operations on
its other registers.
The AXP806_REG_ADDR_EXT was previously configured by Allwinner's
bootloader. Work on U-boot SPL support now allows us to switch
to mainline U-boot, which doesn't do this for us. There might
be other bare minimum bootloaders out there which don't to this
either. It's best to handle this in the kernel.
This patch sets AXP806_REG_ADDR_EXT to 0x10, which is what we
know to be the proper value for a standard AXP806 in slave mode.
Afterwards it will reinitialize the regmap cache, to purge any
invalid stale values.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
Changes since v2:
- Dropped regcache_sync_region() and regmap_reinit_cache() calls.
The write immediately after getting the regmap from the caller
of axp20x_device_probe() is enough.
- Slightly rearranged a few sentences in the comment block.
---
drivers/mfd/axp20x.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
index ed918de84238..81b9ddd10e6c 100644
--- a/drivers/mfd/axp20x.c
+++ b/drivers/mfd/axp20x.c
@@ -31,6 +31,8 @@
#define AXP20X_OFF 0x80
+#define AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE BIT(4)
+
static const char * const axp20x_model_names[] = {
"AXP152",
"AXP202",
@@ -830,6 +832,30 @@ int axp20x_device_probe(struct axp20x_dev *axp20x)
{
int ret;
+ /*
+ * The AXP806 supports either master/standalone or slave mode.
+ * Slave mode allows sharing the serial bus, even with multiple
+ * AXP806 which all have the same hardware address.
+ *
+ * This is done with extra "serial interface address extension",
+ * or AXP806_BUS_ADDR_EXT, and "register address extension", or
+ * AXP806_REG_ADDR_EXT, registers. The former is read-only, with
+ * 1 bit customizable at the factory, and 1 bit depending on the
+ * state of an external pin. The latter is writable. The device
+ * will only respond to operations to its other registers when
+ * the these device addressing bits (in the upper 4 bits of the
+ * registers) match.
+ *
+ * Since we only support an AXP806 chained to an AXP809 in slave
+ * mode, and there isn't any existing hardware which uses AXP806
+ * in master mode, or has 2 AXP806s in the same system, we can
+ * just program the register address extension to the slave mode
+ * address.
+ */
+ if (axp20x->variant == AXP806_ID)
+ regmap_write(axp20x->regmap, AXP806_REG_ADDR_EXT,
+ AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE);
+
ret = regmap_add_irq_chip(axp20x->regmap, axp20x->irq,
IRQF_ONESHOT | IRQF_SHARED, -1,
axp20x->regmap_irq_chip,
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v3] mfd: axp20x: Fix AXP806 access errors on cold boot
@ 2017-01-05 4:01 ` Chen-Yu Tsai
0 siblings, 0 replies; 4+ messages in thread
From: Chen-Yu Tsai @ 2017-01-05 4:01 UTC (permalink / raw)
To: linux-arm-kernel
The AXP806 supports either master/standalone or slave mode.
Slave mode allows sharing the serial bus, even with multiple
AXP806 which all have the same hardware address.
This is done with extra "serial interface address extension",
or AXP806_BUS_ADDR_EXT, and "register address extension", or
AXP806_REG_ADDR_EXT, registers. The former is read-only, with
1 bit customizable at the factory, and 1 bit depending on the
state of an external pin. The latter is writable. Only when
the these device addressing bits (in the upper 4 bits of the
registers) match, will the device respond to operations on
its other registers.
The AXP806_REG_ADDR_EXT was previously configured by Allwinner's
bootloader. Work on U-boot SPL support now allows us to switch
to mainline U-boot, which doesn't do this for us. There might
be other bare minimum bootloaders out there which don't to this
either. It's best to handle this in the kernel.
This patch sets AXP806_REG_ADDR_EXT to 0x10, which is what we
know to be the proper value for a standard AXP806 in slave mode.
Afterwards it will reinitialize the regmap cache, to purge any
invalid stale values.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
Changes since v2:
- Dropped regcache_sync_region() and regmap_reinit_cache() calls.
The write immediately after getting the regmap from the caller
of axp20x_device_probe() is enough.
- Slightly rearranged a few sentences in the comment block.
---
drivers/mfd/axp20x.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
index ed918de84238..81b9ddd10e6c 100644
--- a/drivers/mfd/axp20x.c
+++ b/drivers/mfd/axp20x.c
@@ -31,6 +31,8 @@
#define AXP20X_OFF 0x80
+#define AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE BIT(4)
+
static const char * const axp20x_model_names[] = {
"AXP152",
"AXP202",
@@ -830,6 +832,30 @@ int axp20x_device_probe(struct axp20x_dev *axp20x)
{
int ret;
+ /*
+ * The AXP806 supports either master/standalone or slave mode.
+ * Slave mode allows sharing the serial bus, even with multiple
+ * AXP806 which all have the same hardware address.
+ *
+ * This is done with extra "serial interface address extension",
+ * or AXP806_BUS_ADDR_EXT, and "register address extension", or
+ * AXP806_REG_ADDR_EXT, registers. The former is read-only, with
+ * 1 bit customizable at the factory, and 1 bit depending on the
+ * state of an external pin. The latter is writable. The device
+ * will only respond to operations to its other registers when
+ * the these device addressing bits (in the upper 4 bits of the
+ * registers) match.
+ *
+ * Since we only support an AXP806 chained to an AXP809 in slave
+ * mode, and there isn't any existing hardware which uses AXP806
+ * in master mode, or has 2 AXP806s in the same system, we can
+ * just program the register address extension to the slave mode
+ * address.
+ */
+ if (axp20x->variant == AXP806_ID)
+ regmap_write(axp20x->regmap, AXP806_REG_ADDR_EXT,
+ AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE);
+
ret = regmap_add_irq_chip(axp20x->regmap, axp20x->irq,
IRQF_ONESHOT | IRQF_SHARED, -1,
axp20x->regmap_irq_chip,
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v3] mfd: axp20x: Fix AXP806 access errors on cold boot
2017-01-05 4:01 ` Chen-Yu Tsai
@ 2017-01-05 8:50 ` Lee Jones
-1 siblings, 0 replies; 4+ messages in thread
From: Lee Jones @ 2017-01-05 8:50 UTC (permalink / raw)
To: Chen-Yu Tsai; +Cc: linux-kernel, linux-arm-kernel, linux-sunxi, Mark Brown
On Thu, 05 Jan 2017, Chen-Yu Tsai wrote:
> The AXP806 supports either master/standalone or slave mode.
> Slave mode allows sharing the serial bus, even with multiple
> AXP806 which all have the same hardware address.
>
> This is done with extra "serial interface address extension",
> or AXP806_BUS_ADDR_EXT, and "register address extension", or
> AXP806_REG_ADDR_EXT, registers. The former is read-only, with
> 1 bit customizable at the factory, and 1 bit depending on the
> state of an external pin. The latter is writable. Only when
> the these device addressing bits (in the upper 4 bits of the
> registers) match, will the device respond to operations on
> its other registers.
>
> The AXP806_REG_ADDR_EXT was previously configured by Allwinner's
> bootloader. Work on U-boot SPL support now allows us to switch
> to mainline U-boot, which doesn't do this for us. There might
> be other bare minimum bootloaders out there which don't to this
> either. It's best to handle this in the kernel.
>
> This patch sets AXP806_REG_ADDR_EXT to 0x10, which is what we
> know to be the proper value for a standard AXP806 in slave mode.
> Afterwards it will reinitialize the regmap cache, to purge any
> invalid stale values.
>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
> Changes since v2:
>
> - Dropped regcache_sync_region() and regmap_reinit_cache() calls.
> The write immediately after getting the regmap from the caller
> of axp20x_device_probe() is enough.
>
> - Slightly rearranged a few sentences in the comment block.
> ---
> drivers/mfd/axp20x.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
Much better.
Applied, thanks.
> diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
> index ed918de84238..81b9ddd10e6c 100644
> --- a/drivers/mfd/axp20x.c
> +++ b/drivers/mfd/axp20x.c
> @@ -31,6 +31,8 @@
>
> #define AXP20X_OFF 0x80
>
> +#define AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE BIT(4)
> +
> static const char * const axp20x_model_names[] = {
> "AXP152",
> "AXP202",
> @@ -830,6 +832,30 @@ int axp20x_device_probe(struct axp20x_dev *axp20x)
> {
> int ret;
>
> + /*
> + * The AXP806 supports either master/standalone or slave mode.
> + * Slave mode allows sharing the serial bus, even with multiple
> + * AXP806 which all have the same hardware address.
> + *
> + * This is done with extra "serial interface address extension",
> + * or AXP806_BUS_ADDR_EXT, and "register address extension", or
> + * AXP806_REG_ADDR_EXT, registers. The former is read-only, with
> + * 1 bit customizable at the factory, and 1 bit depending on the
> + * state of an external pin. The latter is writable. The device
> + * will only respond to operations to its other registers when
> + * the these device addressing bits (in the upper 4 bits of the
> + * registers) match.
> + *
> + * Since we only support an AXP806 chained to an AXP809 in slave
> + * mode, and there isn't any existing hardware which uses AXP806
> + * in master mode, or has 2 AXP806s in the same system, we can
> + * just program the register address extension to the slave mode
> + * address.
> + */
> + if (axp20x->variant == AXP806_ID)
> + regmap_write(axp20x->regmap, AXP806_REG_ADDR_EXT,
> + AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE);
> +
> ret = regmap_add_irq_chip(axp20x->regmap, axp20x->irq,
> IRQF_ONESHOT | IRQF_SHARED, -1,
> axp20x->regmap_irq_chip,
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v3] mfd: axp20x: Fix AXP806 access errors on cold boot
@ 2017-01-05 8:50 ` Lee Jones
0 siblings, 0 replies; 4+ messages in thread
From: Lee Jones @ 2017-01-05 8:50 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, 05 Jan 2017, Chen-Yu Tsai wrote:
> The AXP806 supports either master/standalone or slave mode.
> Slave mode allows sharing the serial bus, even with multiple
> AXP806 which all have the same hardware address.
>
> This is done with extra "serial interface address extension",
> or AXP806_BUS_ADDR_EXT, and "register address extension", or
> AXP806_REG_ADDR_EXT, registers. The former is read-only, with
> 1 bit customizable at the factory, and 1 bit depending on the
> state of an external pin. The latter is writable. Only when
> the these device addressing bits (in the upper 4 bits of the
> registers) match, will the device respond to operations on
> its other registers.
>
> The AXP806_REG_ADDR_EXT was previously configured by Allwinner's
> bootloader. Work on U-boot SPL support now allows us to switch
> to mainline U-boot, which doesn't do this for us. There might
> be other bare minimum bootloaders out there which don't to this
> either. It's best to handle this in the kernel.
>
> This patch sets AXP806_REG_ADDR_EXT to 0x10, which is what we
> know to be the proper value for a standard AXP806 in slave mode.
> Afterwards it will reinitialize the regmap cache, to purge any
> invalid stale values.
>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
> Changes since v2:
>
> - Dropped regcache_sync_region() and regmap_reinit_cache() calls.
> The write immediately after getting the regmap from the caller
> of axp20x_device_probe() is enough.
>
> - Slightly rearranged a few sentences in the comment block.
> ---
> drivers/mfd/axp20x.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
Much better.
Applied, thanks.
> diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
> index ed918de84238..81b9ddd10e6c 100644
> --- a/drivers/mfd/axp20x.c
> +++ b/drivers/mfd/axp20x.c
> @@ -31,6 +31,8 @@
>
> #define AXP20X_OFF 0x80
>
> +#define AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE BIT(4)
> +
> static const char * const axp20x_model_names[] = {
> "AXP152",
> "AXP202",
> @@ -830,6 +832,30 @@ int axp20x_device_probe(struct axp20x_dev *axp20x)
> {
> int ret;
>
> + /*
> + * The AXP806 supports either master/standalone or slave mode.
> + * Slave mode allows sharing the serial bus, even with multiple
> + * AXP806 which all have the same hardware address.
> + *
> + * This is done with extra "serial interface address extension",
> + * or AXP806_BUS_ADDR_EXT, and "register address extension", or
> + * AXP806_REG_ADDR_EXT, registers. The former is read-only, with
> + * 1 bit customizable at the factory, and 1 bit depending on the
> + * state of an external pin. The latter is writable. The device
> + * will only respond to operations to its other registers when
> + * the these device addressing bits (in the upper 4 bits of the
> + * registers) match.
> + *
> + * Since we only support an AXP806 chained to an AXP809 in slave
> + * mode, and there isn't any existing hardware which uses AXP806
> + * in master mode, or has 2 AXP806s in the same system, we can
> + * just program the register address extension to the slave mode
> + * address.
> + */
> + if (axp20x->variant == AXP806_ID)
> + regmap_write(axp20x->regmap, AXP806_REG_ADDR_EXT,
> + AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE);
> +
> ret = regmap_add_irq_chip(axp20x->regmap, axp20x->irq,
> IRQF_ONESHOT | IRQF_SHARED, -1,
> axp20x->regmap_irq_chip,
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-01-05 4:01 [PATCH v3] mfd: axp20x: Fix AXP806 access errors on cold boot Chen-Yu Tsai
2017-01-05 4:01 ` Chen-Yu Tsai
2017-01-05 8:50 ` Lee Jones
2017-01-05 8:50 ` Lee Jones
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