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
> 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
On 08/11/2015 01:02 PM, Wolfram Sang wrote: >>> 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. > OK. Will do. Do I have to add myself to MAINTAINER file for this driver? 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
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
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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
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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
>
> 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
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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
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
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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
> CC: Wolfram Sang
> CC: Paul Bolle
> CC: Peter Korsgaard
> CC: Alexander Sverdlin
I can think about external FPGA applications performing MUX function,
so the code looks useful to me.
Acked-by: Alexander Sverdlin
> ---
> 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 specifies the register to control the mux.
> + The 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 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>;
> +
> + si5338: clock-generator@70 {
> +
