Re: [U-Boot] [PATCH v2 2/6] dm: core: Allow multiple drivers to bind for a single node

Hi Philipp,

On 22 February 2017 at 13:47, Philipp Tomsich philipp.tomsich@theobroma-systems.com wrote:

Currently, driver binding stops once it encounters the first compatible driver that doesn't refuse to bind. However, there are cases where a single node will need to be handled by multiple driver classes. For those cases we provide a configurable option to continue to bind after the first driver has been found.

The first use cases for this are from the DM conversion of the sunxi (Allwinner) architecture:

• pinctrl (UCLASS_PINCTRL) and gpio (UCLASS_GPIO) drivers need to bind against a single node
• clock (UCLASS_CLK) and reset (UCLASS_RESET) drivers also need to bind against a single node

Does linux work this way? Another approach would be to have a separate MISC driver with two children, one pinctrl, one clk.

Signed-off-by: Philipp Tomsich philipp.tomsich@theobroma-systems.com

drivers/core/Kconfig | 14 ++++++++++++++ drivers/core/lists.c | 12 +++++++++++- 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig index 8749561..913101c 100644 --- a/drivers/core/Kconfig +++ b/drivers/core/Kconfig @@ -31,6 +31,20 @@ config DM_WARN This will cause dm_warn() to be compiled out - it will do nothing when called.

+config DM_ALLOW_MULTIPLE_DRIVERS

•    bool "Allow multiple drivers to bind for one node"
  

•   depends on DM
  

•   default n
  

You should be able to drop this line.

•   help
  

•     The driver model in U-Boot originally did not allow multiple
  

•     drivers to bind for a single device node.
  

•     If enabled, multiple drivers can now bind for a single node
  

•     by using the same compatible string for matching: lists_bind_fdt()
  

•     will assume that binding multiple drivers is desirable, if the
  

•     caller does not request the pointer to the udevice structure to
  

•     be returned (i.e. if devp is NULL).
  

Please update the function documentation in the header file.

config DM_DEVICE_REMOVE bool "Support device removal" depends on DM diff --git a/drivers/core/lists.c b/drivers/core/lists.c index 23b6ba7..52efe69 100644 --- a/drivers/core/lists.c +++ b/drivers/core/lists.c @@ -166,7 +166,11 @@ int lists_bind_fdt(struct udevice *parent, const void *blob, int offset, dm_dbg(" - attempt to match compatible string '%s'\n", compat);

•           for (entry = driver; entry != driver + n_ents; entry++) {
  

•           entry = driver;
  

+#if defined(CONFIG_DM_ALLOW_MULTIPLE_DRIVERS)

•   allow_more_matches:
  

+#endif

•           for (; entry != driver + n_ents; entry++) {
                    ret = driver_check_compatible(entry->of_match, &id,
                                                  compat);
                    if (!ret)
  

@@ -190,6 +194,12 @@ int lists_bind_fdt(struct udevice *parent, const void *blob, int offset, found = true; if (devp) *devp = dev; +#if defined(CONFIG_DM_ALLOW_MULTIPLE_DRIVERS)

Can you make this a variable, e.g. with allow_multiple = IS_ENABLED(DM_ALLOW_MULTIPLE_DRIVERS)? I'd prefer not to add #ifdefs in this file.

•                   else {
  

•                           entry++;
  

•                           goto allow_more_matches;
  

Is it possible to loop without using goto?

•                   }
  

+#endif } break; } -- 1.9.1

Regards, Simon