[PATCH 0/2] Kconfig: Add an I2C_DEVICES device group

[PATCH 0/2] Kconfig: Add an I2C_DEVICES device group

[Peter Maydell]

This patchset adds a new Kconfig "device group" for I2C devices which
a user might reasonably want to plug in to an arbitrary i2c bus via
the command line.  This follows the approach we use for PCI devices:
generally-usable i2c devices have
       default y if I2C_DEVICES
and board models with user-accessible i2c buses have
       imply I2C_DEVICES

This means that when building a board model that pulls in the device
group, the devices are all compiled in and available for use. 
(Previously they would happen to be present and usable only if some
other board that explicitly pulled that device in happened to also be
built into the same QEMU binary.)

I have been fairly conservative in marking devices as being in the
group and in marking board models as pulling in the group; feel free
to suggest changes.

In particular I've only added 'imply I2C_DEVICES' to arm boards. 
Grepping through Kconfig files I only found the PPC boards e500 and
ppc44x that enable some kind of i2c controller anyway.

The immediate motivation here is that the recently added lsm303dlhc
magnetometer isn't currently built unless the user manually adds it
to their config, because as it happens no boards have it as a
hard-wired device.

thanks
-- PMM

Peter Maydell (2):
  Kconfig: Add I2C_DEVICES device group
  Kconfig: Add 'imply I2C_DEVICES' on boards with available i2c bus

 docs/devel/kconfig.rst |  8 ++++++--
 hw/arm/Kconfig         | 10 ++++++++++
 hw/i2c/Kconfig         |  5 +++++
 hw/rtc/Kconfig         |  2 ++
 hw/sensor/Kconfig      |  5 +++++
 5 files changed, 28 insertions(+), 2 deletions(-)

-- 
2.25.1

[PATCH 1/2] Kconfig: Add I2C_DEVICES device group

[Peter Maydell]

Currently there is no way for a board model's Kconfig stanza to
say "I have an i2c bus which the user can plug an i2c device into,
build all the free-standing i2c devices". The Kconfig mechanism
for this is the "device group". Add an I2C_DEVICES group along
the same lines as the existing PCI_DEVICES. Simple free-standing
i2c devices which a user might plausibly want to be able to
plug in on the QEMU commandline should have
   default y if I2C_DEVICES
and board models which have an i2c bus that is user-accessible
should use
   imply I2C_DEVICES
to cause those pluggable devices to be built.

In this commit we mark only a fairly conservative set of i2c devices
as belonging to the I2C_DEVICES group: the simple sensors and RTCs
(not including PMBus devices or devices which need GPIO lines to be
connected).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Feel free to suggest other i2c devices that should be marked
as in the group; as I say, I erred on the side of not putting
devices in the group.
---
 docs/devel/kconfig.rst | 8 ++++++--
 hw/i2c/Kconfig         | 5 +++++
 hw/rtc/Kconfig         | 2 ++
 hw/sensor/Kconfig      | 5 +++++
 4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/docs/devel/kconfig.rst b/docs/devel/kconfig.rst
index a1cdbec7512..aa5042f1569 100644
--- a/docs/devel/kconfig.rst
+++ b/docs/devel/kconfig.rst
@@ -192,11 +192,15 @@ declares its dependencies in different ways:
   no directive and are not used in the Makefile either; they only appear
   as conditions for ``default y`` directives.
 
-  QEMU currently has two device groups, ``PCI_DEVICES`` and
-  ``TEST_DEVICES``.  PCI devices usually have a ``default y if
+  QEMU currently has three device groups, ``PCI_DEVICES``, ``I2C_DEVICES``,
+  and ``TEST_DEVICES``.  PCI devices usually have a ``default y if
   PCI_DEVICES`` directive rather than just ``default y``.  This lets
   some boards (notably s390) easily support a subset of PCI devices,
   for example only VFIO (passthrough) and virtio-pci devices.
+  ``I2C_DEVICES`` is similar to ``PCI_DEVICES``. It contains i2c devices
+  that users might reasonably want to plug in to an i2c bus on any
+  board (and not ones which are very board-specific or that need
+  to be wired up in a way that can't be done on the command line).
   ``TEST_DEVICES`` instead is used for devices that are rarely used on
   production virtual machines, but provide useful hooks to test QEMU
   or KVM.
diff --git a/hw/i2c/Kconfig b/hw/i2c/Kconfig
index 8217cb50411..9bb8870517f 100644
--- a/hw/i2c/Kconfig
+++ b/hw/i2c/Kconfig
@@ -1,6 +1,11 @@
 config I2C
     bool
 
+config I2C_DEVICES
+    # Device group for i2c devices which can reasonably be user-plugged
+    # to any board's i2c bus
+    bool
+
 config SMBUS
     bool
     select I2C
diff --git a/hw/rtc/Kconfig b/hw/rtc/Kconfig
index f06e133b8a2..730c272bc54 100644
--- a/hw/rtc/Kconfig
+++ b/hw/rtc/Kconfig
@@ -1,10 +1,12 @@
 config DS1338
     bool
     depends on I2C
+    default y if I2C_DEVICES
 
 config M41T80
     bool
     depends on I2C
+    default y if I2C_DEVICES
 
 config M48T59
     bool
diff --git a/hw/sensor/Kconfig b/hw/sensor/Kconfig
index b317f91b7b4..215944decc7 100644
--- a/hw/sensor/Kconfig
+++ b/hw/sensor/Kconfig
@@ -1,18 +1,22 @@
 config TMP105
     bool
     depends on I2C
+    default y if I2C_DEVICES
 
 config TMP421
     bool
     depends on I2C
+    default y if I2C_DEVICES
 
 config DPS310
     bool
     depends on I2C
+    default y if I2C_DEVICES
 
 config EMC141X
     bool
     depends on I2C
+    default y if I2C_DEVICES
 
 config ADM1272
     bool
@@ -25,3 +29,4 @@ config MAX34451
 config LSM303DLHC_MAG
     bool
     depends on I2C
+    default y if I2C_DEVICES
-- 
2.25.1

[PATCH 2/2] Kconfig: Add 'imply I2C_DEVICES' on boards with available i2c bus

[Peter Maydell]

For arm boards with an i2c bus which a user could reasonably
want to plug arbitrary devices, add 'imply I2C_DEVICES' to the
Kconfig stanza.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Again, slightly arbitrary but erring on the side of conservative.
I leave non-Arm architectures out (afaict only ppc ppc4xx and e500
enable any kind of I2C controller in their Kconfig anyway).
---
 hw/arm/Kconfig | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
index 2e0049196d6..6945330030e 100644
--- a/hw/arm/Kconfig
+++ b/hw/arm/Kconfig
@@ -46,6 +46,7 @@ config DIGIC
 
 config EXYNOS4
     bool
+    imply I2C_DEVICES
     select A9MPCORE
     select I2C
     select LAN9118
@@ -184,6 +185,7 @@ config REALVIEW
     bool
     imply PCI_DEVICES
     imply PCI_TESTDEV
+    imply I2C_DEVICES
     select SMC91C111
     select LAN9118
     select A9MPCORE
@@ -229,6 +231,7 @@ config SABRELITE
 
 config STELLARIS
     bool
+    imply I2C_DEVICES
     select ARM_V7M
     select CMSDK_APB_WATCHDOG
     select I2C
@@ -406,6 +409,7 @@ config NPCM7XX
 
 config FSL_IMX25
     bool
+    imply I2C_DEVICES
     select IMX
     select IMX_FEC
     select IMX_I2C
@@ -414,6 +418,7 @@ config FSL_IMX25
 
 config FSL_IMX31
     bool
+    imply I2C_DEVICES
     select SERIAL
     select IMX
     select IMX_I2C
@@ -422,6 +427,7 @@ config FSL_IMX31
 
 config FSL_IMX6
     bool
+    imply I2C_DEVICES
     select A9MPCORE
     select IMX
     select IMX_FEC
@@ -450,6 +456,7 @@ config ASPEED_SOC
 
 config MPS2
     bool
+    imply I2C_DEVICES
     select ARMSSE
     select LAN9118
     select MPS2_FPGAIO
@@ -466,6 +473,7 @@ config FSL_IMX7
     bool
     imply PCI_DEVICES
     imply TEST_DEVICES
+    imply I2C_DEVICES
     select A15MPCORE
     select PCI
     select IMX
@@ -481,6 +489,7 @@ config ARM_SMMUV3
 
 config FSL_IMX6UL
     bool
+    imply I2C_DEVICES
     select A15MPCORE
     select IMX
     select IMX_FEC
@@ -495,6 +504,7 @@ config MICROBIT
 
 config NRF51_SOC
     bool
+    imply I2C_DEVICES
     select I2C
     select ARM_V7M
     select UNIMP
-- 
2.25.1

Re: [PATCH 0/2] Kconfig: Add an I2C_DEVICES device group

[Paolo Bonzini]

On 2/8/22 16:59, Peter Maydell wrote:
> This patchset adds a new Kconfig "device group" for I2C devices which
> a user might reasonably want to plug in to an arbitrary i2c bus via
> the command line.  This follows the approach we use for PCI devices:
> generally-usable i2c devices have
>         default y if I2C_DEVICES
> and board models with user-accessible i2c buses have
>         imply I2C_DEVICES
> 
> This means that when building a board model that pulls in the device
> group, the devices are all compiled in and available for use.
> (Previously they would happen to be present and usable only if some
> other board that explicitly pulled that device in happened to also be
> built into the same QEMU binary.)
> 
> I have been fairly conservative in marking devices as being in the
> group and in marking board models as pulling in the group; feel free
> to suggest changes.
> 
> In particular I've only added 'imply I2C_DEVICES' to arm boards.
> Grepping through Kconfig files I only found the PPC boards e500 and
> ppc44x that enable some kind of i2c controller anyway.
> 
> The immediate motivation here is that the recently added lsm303dlhc
> magnetometer isn't currently built unless the user manually adds it
> to their config, because as it happens no boards have it as a
> hard-wired device.

Acked-by: Paolo Bonzini <pbonzini@redhat.com>

> thanks
> -- PMM
> 
> Peter Maydell (2):
>    Kconfig: Add I2C_DEVICES device group
>    Kconfig: Add 'imply I2C_DEVICES' on boards with available i2c bus
> 
>   docs/devel/kconfig.rst |  8 ++++++--
>   hw/arm/Kconfig         | 10 ++++++++++
>   hw/i2c/Kconfig         |  5 +++++
>   hw/rtc/Kconfig         |  2 ++
>   hw/sensor/Kconfig      |  5 +++++
>   5 files changed, 28 insertions(+), 2 deletions(-)
> 

Re: [PATCH 1/2] Kconfig: Add I2C_DEVICES device group

[Hao Wu]

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On Tue, Feb 8, 2022 at 9:55 AM Peter Maydell <peter.maydell@linaro.org>
wrote:

> Currently there is no way for a board model's Kconfig stanza to
> say "I have an i2c bus which the user can plug an i2c device into,
> build all the free-standing i2c devices". The Kconfig mechanism
> for this is the "device group". Add an I2C_DEVICES group along
> the same lines as the existing PCI_DEVICES. Simple free-standing
> i2c devices which a user might plausibly want to be able to
> plug in on the QEMU commandline should have
>    default y if I2C_DEVICES
> and board models which have an i2c bus that is user-accessible
> should use
>    imply I2C_DEVICES
> to cause those pluggable devices to be built.
>
> In this commit we mark only a fairly conservative set of i2c devices
> as belonging to the I2C_DEVICES group: the simple sensors and RTCs
> (not including PMBus devices or devices which need GPIO lines to be
> connected).
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>
Reviewed-by: Hao Wu <wuhaotsh@google.com>

> ---
> Feel free to suggest other i2c devices that should be marked
> as in the group; as I say, I erred on the side of not putting
> devices in the group.
> ---
>  docs/devel/kconfig.rst | 8 ++++++--
>  hw/i2c/Kconfig         | 5 +++++
>  hw/rtc/Kconfig         | 2 ++
>  hw/sensor/Kconfig      | 5 +++++
>  4 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/docs/devel/kconfig.rst b/docs/devel/kconfig.rst
> index a1cdbec7512..aa5042f1569 100644
> --- a/docs/devel/kconfig.rst
> +++ b/docs/devel/kconfig.rst
> @@ -192,11 +192,15 @@ declares its dependencies in different ways:
>    no directive and are not used in the Makefile either; they only appear
>    as conditions for ``default y`` directives.
>
> -  QEMU currently has two device groups, ``PCI_DEVICES`` and
> -  ``TEST_DEVICES``.  PCI devices usually have a ``default y if
> +  QEMU currently has three device groups, ``PCI_DEVICES``,
> ``I2C_DEVICES``,
> +  and ``TEST_DEVICES``.  PCI devices usually have a ``default y if
>    PCI_DEVICES`` directive rather than just ``default y``.  This lets
>    some boards (notably s390) easily support a subset of PCI devices,
>    for example only VFIO (passthrough) and virtio-pci devices.
> +  ``I2C_DEVICES`` is similar to ``PCI_DEVICES``. It contains i2c devices
> +  that users might reasonably want to plug in to an i2c bus on any
> +  board (and not ones which are very board-specific or that need
> +  to be wired up in a way that can't be done on the command line).
>    ``TEST_DEVICES`` instead is used for devices that are rarely used on
>    production virtual machines, but provide useful hooks to test QEMU
>    or KVM.
> diff --git a/hw/i2c/Kconfig b/hw/i2c/Kconfig
> index 8217cb50411..9bb8870517f 100644
> --- a/hw/i2c/Kconfig
> +++ b/hw/i2c/Kconfig
> @@ -1,6 +1,11 @@
>  config I2C
>      bool
>
> +config I2C_DEVICES
> +    # Device group for i2c devices which can reasonably be user-plugged
> +    # to any board's i2c bus
> +    bool
> +
>  config SMBUS
>      bool
>      select I2C
> diff --git a/hw/rtc/Kconfig b/hw/rtc/Kconfig
> index f06e133b8a2..730c272bc54 100644
> --- a/hw/rtc/Kconfig
> +++ b/hw/rtc/Kconfig
> @@ -1,10 +1,12 @@
>  config DS1338
>      bool
>      depends on I2C
> +    default y if I2C_DEVICES
>
>  config M41T80
>      bool
>      depends on I2C
> +    default y if I2C_DEVICES
>
>  config M48T59
>      bool
> diff --git a/hw/sensor/Kconfig b/hw/sensor/Kconfig
> index b317f91b7b4..215944decc7 100644
> --- a/hw/sensor/Kconfig
> +++ b/hw/sensor/Kconfig
> @@ -1,18 +1,22 @@
>  config TMP105
>      bool
>      depends on I2C
> +    default y if I2C_DEVICES
>
>  config TMP421
>      bool
>      depends on I2C
> +    default y if I2C_DEVICES
>
>  config DPS310
>      bool
>      depends on I2C
> +    default y if I2C_DEVICES
>
>  config EMC141X
>      bool
>      depends on I2C
> +    default y if I2C_DEVICES
>
>  config ADM1272
>      bool
> @@ -25,3 +29,4 @@ config MAX34451
>  config LSM303DLHC_MAG
>      bool
>      depends on I2C
> +    default y if I2C_DEVICES
> --
> 2.25.1
>
>
>

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Re: [PATCH 2/2] Kconfig: Add 'imply I2C_DEVICES' on boards with available i2c bus

[Hao Wu]

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On Tue, Feb 8, 2022 at 9:23 AM Peter Maydell <peter.maydell@linaro.org>
wrote:

> For arm boards with an i2c bus which a user could reasonably
> want to plug arbitrary devices, add 'imply I2C_DEVICES' to the
> Kconfig stanza.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>
Reviewed-by: Hao Wu <wuhaotsh@google.com>

> ---
> Again, slightly arbitrary but erring on the side of conservative.
> I leave non-Arm architectures out (afaict only ppc ppc4xx and e500
> enable any kind of I2C controller in their Kconfig anyway).
> ---
>  hw/arm/Kconfig | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
> index 2e0049196d6..6945330030e 100644
> --- a/hw/arm/Kconfig
> +++ b/hw/arm/Kconfig
> @@ -46,6 +46,7 @@ config DIGIC
>
>  config EXYNOS4
>      bool
> +    imply I2C_DEVICES
>      select A9MPCORE
>      select I2C
>      select LAN9118
> @@ -184,6 +185,7 @@ config REALVIEW
>      bool
>      imply PCI_DEVICES
>      imply PCI_TESTDEV
> +    imply I2C_DEVICES
>      select SMC91C111
>      select LAN9118
>      select A9MPCORE
> @@ -229,6 +231,7 @@ config SABRELITE
>
>  config STELLARIS
>      bool
> +    imply I2C_DEVICES
>      select ARM_V7M
>      select CMSDK_APB_WATCHDOG
>      select I2C
> @@ -406,6 +409,7 @@ config NPCM7XX
>
>  config FSL_IMX25
>      bool
> +    imply I2C_DEVICES
>      select IMX
>      select IMX_FEC
>      select IMX_I2C
> @@ -414,6 +418,7 @@ config FSL_IMX25
>
>  config FSL_IMX31
>      bool
> +    imply I2C_DEVICES
>      select SERIAL
>      select IMX
>      select IMX_I2C
> @@ -422,6 +427,7 @@ config FSL_IMX31
>
>  config FSL_IMX6
>      bool
> +    imply I2C_DEVICES
>      select A9MPCORE
>      select IMX
>      select IMX_FEC
> @@ -450,6 +456,7 @@ config ASPEED_SOC
>
>  config MPS2
>      bool
> +    imply I2C_DEVICES
>      select ARMSSE
>      select LAN9118
>      select MPS2_FPGAIO
> @@ -466,6 +473,7 @@ config FSL_IMX7
>      bool
>      imply PCI_DEVICES
>      imply TEST_DEVICES
> +    imply I2C_DEVICES
>      select A15MPCORE
>      select PCI
>      select IMX
> @@ -481,6 +489,7 @@ config ARM_SMMUV3
>
>  config FSL_IMX6UL
>      bool
> +    imply I2C_DEVICES
>      select A15MPCORE
>      select IMX
>      select IMX_FEC
> @@ -495,6 +504,7 @@ config MICROBIT
>
>  config NRF51_SOC
>      bool
> +    imply I2C_DEVICES
>      select I2C
>      select ARM_V7M
>      select UNIMP
> --
> 2.25.1
>
>
>

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Re: [PATCH 0/2] Kconfig: Add an I2C_DEVICES device group

[Philippe Mathieu-Daudé via]

On 8/2/22 16:59, Peter Maydell wrote:

> Peter Maydell (2):
>    Kconfig: Add I2C_DEVICES device group
>    Kconfig: Add 'imply I2C_DEVICES' on boards with available i2c bus
> 
>   docs/devel/kconfig.rst |  8 ++++++--
>   hw/arm/Kconfig         | 10 ++++++++++
>   hw/i2c/Kconfig         |  5 +++++
>   hw/rtc/Kconfig         |  2 ++
>   hw/sensor/Kconfig      |  5 +++++
>   5 files changed, 28 insertions(+), 2 deletions(-)

Series:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>