Re: [Patch v3] driver/i2c/mux: Add register-based mux i2c-mux-reg
Do I have to add myself to MAINTAINER file for this driver? Do you want to maintain this driver? I prefer not, if that is OK. Not my most favourite answer, but yes, it is ok ;) -- To unsubscribe from this list: send the line unsubscribe linux-i2c in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Patch v3] driver/i2c/mux: Add register-based mux i2c-mux-reg
On 08/11/2015 06:35 PM, Wolfram Sang wrote: Do I have to add myself to MAINTAINER file for this driver? Do you want to maintain this driver? I prefer not, if that is OK. York -- To unsubscribe from this list: send the line unsubscribe linux-i2c in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Patch v3] driver/i2c/mux: Add register-based mux i2c-mux-reg
On Thu, Jun 18, 2015 at 12:57:38PM -0700, York Sun wrote:
Based on i2c-mux-gpio driver, similarly the register-based mux
switch from one bus to another by setting a single register.
The register can be on PCIe bus, local bus, or any memory-mapped
address. The endianness of such register can be specified in device
tree if used, or in platform data.
Signed-off-by: York Sun york...@freescale.com
Thanks for this driver!
...
+- no-read: The existence indicates reading the register is not allowed.
Given that we have read-only properties already, I'd prefer this one
to be write-only.
+For each i2c child node, an I2C child bus will be created. They will
+be numbered based on their order in the device tree.
This is a Linux specific detail (which can be overridden by aliases), so
it should not be in this document, I'd say.
diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index f6d313e..77c1257 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -29,6 +29,17 @@ config I2C_MUX_GPIO
This driver can also be built as a module. If so, the module
will be called i2c-mux-gpio.
+config I2C_MUX_REG
+ tristate Register-based I2C multiplexer
+ help
+ If you say yes to this option, support will be included for a
+ register based I2C multiplexer. This driver provides access to
+ I2C busses connected through a MUX, which is controlled
+ by a sinple register.
Typo here. And keep the sorting, please.
obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o
+obj-$(CONFIG_I2C_MUX_REG)+= i2c-mux-reg.o
Keep the sorting, please.
obj-$(CONFIG_I2C_MUX_PCA9541)+= i2c-mux-pca9541.o
obj-$(CONFIG_I2C_MUX_PCA954x)+= i2c-mux-pca954x.o
obj-$(CONFIG_I2C_MUX_PINCTRL)+= i2c-mux-pinctrl.o
+ adapter = of_find_i2c_adapter_by_node(adapter_np);
+ if (!adapter) {
+ dev_err(pdev-dev, Cannot find parent bus\n);
I don't think we should print something when deferring.
+ return -EPROBE_DEFER;
+ }
+ mux-parent = adapter;
+ mux-data.parent = i2c_adapter_id(adapter);
+ put_device(adapter-dev);
+
+ mux-data.n_values = of_get_child_count(np);
+ if (of_find_property(np, little-endian, NULL)) {
You should check for a big-endian property as well, no?
+ parent = i2c_get_adapter(mux-data.parent);
+ if (!parent) {
+ dev_err(pdev-dev, Parent adapter (%d) not found\n,
+ mux-data.parent);
+ return -EPROBE_DEFER;
Ditto about printing when deferred probing.
+static int i2c_mux_reg_remove(struct platform_device *pdev)
+{
+ struct regmux *mux = platform_get_drvdata(pdev);
+ int i;
+
+ for (i = 0; i mux-data.n_values; i++)
+ i2c_del_mux_adapter(mux-adap[i]);
+
+ i2c_put_adapter(mux-parent);
+
+ dev_dbg(pdev-dev, Removed\n);
No need for that debug. The driver core has debug output for that.
Thanks,
Wolfram
signature.asc
Description: Digital signature
Re: [Patch v3] driver/i2c/mux: Add register-based mux i2c-mux-reg
On 08/11/2015 08:39 AM, Wolfram Sang wrote:
On Thu, Jun 18, 2015 at 12:57:38PM -0700, York Sun wrote:
Based on i2c-mux-gpio driver, similarly the register-based mux
switch from one bus to another by setting a single register.
The register can be on PCIe bus, local bus, or any memory-mapped
address. The endianness of such register can be specified in device
tree if used, or in platform data.
Signed-off-by: York Sun york...@freescale.com
Thanks for this driver!
...
+- no-read: The existence indicates reading the register is not allowed.
Given that we have read-only properties already, I'd prefer this one
to be write-only.
Sure. That's easy to fix.
+For each i2c child node, an I2C child bus will be created. They will
+be numbered based on their order in the device tree.
This is a Linux specific detail (which can be overridden by aliases), so
it should not be in this document, I'd say.
OK. I can remove it.
diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index f6d313e..77c1257 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -29,6 +29,17 @@ config I2C_MUX_GPIO
This driver can also be built as a module. If so, the module
will be called i2c-mux-gpio.
+config I2C_MUX_REG
+tristate Register-based I2C multiplexer
+help
+ If you say yes to this option, support will be included for a
+ register based I2C multiplexer. This driver provides access to
+ I2C busses connected through a MUX, which is controlled
+ by a sinple register.
Typo here. And keep the sorting, please.
Will fix.
obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o
+obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o
Keep the sorting, please.
obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
+adapter = of_find_i2c_adapter_by_node(adapter_np);
+if (!adapter) {
+dev_err(pdev-dev, Cannot find parent bus\n);
I don't think we should print something when deferring.
OK.
+return -EPROBE_DEFER;
+}
+mux-parent = adapter;
+mux-data.parent = i2c_adapter_id(adapter);
+put_device(adapter-dev);
+
+mux-data.n_values = of_get_child_count(np);
+if (of_find_property(np, little-endian, NULL)) {
You should check for a big-endian property as well, no?
I use the little-endian as an option to indicate the nature of litten-endian
register. It is default to big-endian if this property doesn't exist. I prefer
this way unless you strongly suggest to add both and throw out an error if
neither exists.
+parent = i2c_get_adapter(mux-data.parent);
+if (!parent) {
+dev_err(pdev-dev, Parent adapter (%d) not found\n,
+mux-data.parent);
+return -EPROBE_DEFER;
Ditto about printing when deferred probing.
OK.
+static int i2c_mux_reg_remove(struct platform_device *pdev)
+{
+struct regmux *mux = platform_get_drvdata(pdev);
+int i;
+
+for (i = 0; i mux-data.n_values; i++)
+i2c_del_mux_adapter(mux-adap[i]);
+
+i2c_put_adapter(mux-parent);
+
+dev_dbg(pdev-dev, Removed\n);
No need for that debug. The driver core has debug output for that.
Will remove.
Thanks for reviewing. I will send a new version after testing.
York
--
To unsubscribe from this list: send the line unsubscribe linux-i2c in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Patch v3] driver/i2c/mux: Add register-based mux i2c-mux-reg
+ if (of_find_property(np, little-endian, NULL)) {
You should check for a big-endian property as well, no?
I use the little-endian as an option to indicate the nature of litten-endian
register. It is default to big-endian if this property doesn't exist. I prefer
this way unless you strongly suggest to add both and throw out an error if
neither exists.
I'd think that little-endian or big-endian force a setting. If none
is present, we shall take the CPU endianess. Or am I overlooking
something?
Oh, and I forgot the biggest issue: I get build errors, because
__LITTLE_ENDIAN__ should be __LITTLE_ENDIAN. Is this a recent change or
why did it work for you?
Thanks for the quick response,
Wolfram
signature.asc
Description: Digital signature
Re: [Patch v3] driver/i2c/mux: Add register-based mux i2c-mux-reg
On 08/11/2015 09:16 AM, Wolfram Sang wrote:
+ if (of_find_property(np, little-endian, NULL)) {
You should check for a big-endian property as well, no?
I use the little-endian as an option to indicate the nature of litten-endian
register. It is default to big-endian if this property doesn't exist. I
prefer
this way unless you strongly suggest to add both and throw out an error if
neither exists.
I'd think that little-endian or big-endian force a setting. If none
is present, we shall take the CPU endianess. Or am I overlooking
something?
You are right. The current code checks for littel-endian property. If missing,
the CPU endianess is used. Do you prefer to check littlen-endian first, if
missing then big-endian, if both missing then use CPU endianess?
Oh, and I forgot the biggest issue: I get build errors, because
__LITTLE_ENDIAN__ should be __LITTLE_ENDIAN. Is this a recent change or
why did it work for you?
I tested it on 4.0.4 kernel. I see a lot of reference of __LITTLE_ENDIAN__. I
will test the new patch on the latest kernel.
York
--
To unsubscribe from this list: send the line unsubscribe linux-i2c in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Patch v3] driver/i2c/mux: Add register-based mux i2c-mux-reg
I'd think that little-endian or big-endian force a setting. If none is present, we shall take the CPU endianess. Or am I overlooking something? You are right. The current code checks for littel-endian property. If missing, the CPU endianess is used. Do you prefer to check littlen-endian first, if missing then big-endian, if both missing then use CPU endianess? Yes. Do it like this. signature.asc Description: Digital signature
Re: [Patch v3] driver/i2c/mux: Add register-based mux i2c-mux-reg
Do I have to add myself to MAINTAINER file for this driver? Do you want to maintain this driver? signature.asc Description: Digital signature
Re: [Patch v3] driver/i2c/mux: Add register-based mux i2c-mux-reg
Hi!
On 18/06/15 21:57, ext York Sun wrote:
Based on i2c-mux-gpio driver, similarly the register-based mux
switch from one bus to another by setting a single register.
The register can be on PCIe bus, local bus, or any memory-mapped
address. The endianness of such register can be specified in device
tree if used, or in platform data.
Signed-off-by: York Sun york...@freescale.com
CC: Wolfram Sang w...@the-dreams.de
CC: Paul Bolle pebo...@tiscali.nl
CC: Peter Korsgaard peter.korsga...@barco.com
CC: Alexander Sverdlin alexander.sverd...@nokia.com
I can think about external FPGA applications performing MUX function,
so the code looks useful to me.
Acked-by: Alexander Sverdlin alexander.sverd...@nokia.com
---
According to Alexander's feedback, readback is added. Different sizes
are supported. I stick with iowrite but adding an option to use iowrite
big endian in in case needed. Both big- and little-endian are tested.
Comments are updated.
Change log:
v3: Add support of both big- and little-endian register
Add readback after writing to register
Add no-read option. By default, readback is alowed.
Fix using chan_id transferred back from i2c-mux. It was mistakenly
used as an index. It is actually the data to be written.
v2: Update to GPLv2+ licence header
Use iowrite instead of direct dereference the pointer to write register
Add support of difference register size of 1/2/4 bytes
Remove i2c_put_adapter(parent) in probe fucntion
Replace multiple dev_info() with dev_dbg()
Add idle_in_use variable to gate using idle value
Add __iomem for register pointer
Move platform data header file to include/linux/platform_data/
.../devicetree/bindings/i2c/i2c-mux-reg.txt| 75 +
drivers/i2c/muxes/Kconfig | 11 +
drivers/i2c/muxes/Makefile |1 +
drivers/i2c/muxes/i2c-mux-reg.c| 299
include/linux/platform_data/i2c-mux-reg.h | 44 +++
5 files changed, 430 insertions(+)
create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
create mode 100644 drivers/i2c/muxes/i2c-mux-reg.c
create mode 100644 include/linux/platform_data/i2c-mux-reg.h
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
new file mode 100644
index 000..6e3197f
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
@@ -0,0 +1,75 @@
+Register-based I2C Bus Mux
+
+This binding describes an I2C bus multiplexer that uses a single register
+to route the I2C signals.
+
+Required properties:
+- compatible: i2c-mux-reg
+- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
+ port is connected to.
+* Standard I2C mux properties. See mux.txt in this directory.
+* I2C child bus nodes. See mux.txt in this directory.
+
+Optional properties:
+- reg: this pair of offset size specifies the register to control the mux.
+ The offset size depends on its parent node. It can be any memory-mapped
+ address. The size must be either 1, 2, or 4 bytes. If reg is omitted, the
+ resource of this device will be used.
+- little-endian: The existence indicates the register is in little endian.
+ If omitted, the endianness of the host will be used.
+- no-read: The existence indicates reading the register is not allowed.
+- idle-state: value to set the muxer to when idle. When no value is
+ given, it defaults to the last value used.
+
+For each i2c child node, an I2C child bus will be created. They will
+be numbered based on their order in the device tree.
+
+Whenever an access is made to a device on a child bus, the value set
+in the revelant node's reg property will be output to the register.
+
+If an idle state is defined, using the idle-state (optional) property,
+whenever an access is not being made to a device on a child bus, the
+register will be set according to the idle value.
+
+If an idle state is not defined, the most recently used value will be
+left programmed into the register.
+
+Example of a mux on PCIe card, the host is a powerpc SoC (big endian):
+
+ i2c-mux {
+ /* the offset size depends on the address translation
+ * of the parent device. If omitted, device resource
+ * will be used instead. The size is to determine
+ * whether iowrite32, iowrite16, or iowrite8 will be used.
+ */
+ reg = 0x6028 0x4;
+ little-endian; /* little endian register on PCIe */
+ compatible = i2c-mux-reg;
+ #address-cells = 1;
+ #size-cells = 0;
+ i2c-parent = i2c1;
+ i2c@0 {
+ reg = 0;
+ #address-cells = 1;
+ #size-cells = 0;
+
+
