Messages in this thread |  | | Date | Tue, 28 Jul 2020 10:27:11 +0200 | From | Michael Walle <> | Subject | Re: [PATCH v6 01/13] mfd: add simple regmap based I2C driver |
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Am 2020-07-28 10:15, schrieb Lee Jones: > On Tue, 28 Jul 2020, Michael Walle wrote: > >> Am 2020-07-28 09:19, schrieb Lee Jones: >> > On Sun, 26 Jul 2020, Michael Walle wrote: >> > >> > > There are I2C devices which contain several different functions but >> > > doesn't require any special access functions. For these kind of >> > > drivers >> > > an I2C regmap should be enough. >> > > >> > > Create an I2C driver which creates an I2C regmap and enumerates its >> > > children. If a device wants to use this as its MFD core driver, it has >> > > to add an individual compatible string. It may provide its own regmap >> > > configuration. >> > > >> > > Subdevices can use dev_get_regmap() on the parent to get their regmap >> > > instance. >> > > >> > > Signed-off-by: Michael Walle <michael@walle.cc> >> > > --- >> > > Changes since v5: >> > > - removed "select MFD_CORE" in Kconfig >> > > - removed help text in Kconfig, we assume that the users of this >> > >> > That's the opposite of what I asked for. >> >> What is the use to describe the symbol, if it is not user selectable? >> I'm not aware this is done anywhere in the kernel, am I missing >> something? > > You mean in menuconfig? > > I find 'help's helpful even outside of menuconfig. > > Surely I'm not the only one who reads them 'raw'?
Its already available in the header of the file. But sure, I can copy it.
>> > > driver will have a "select MFD_SIMPLE_MFD_I2C". Instead added >> > > a small description to the driver itself. >> > > - removed "struct simple_mfd_i2c_config" and use regmap_config >> > > directly >> > > - changed builtin_i2c_driver() to module_i2c_driver(), added >> > > MODULE_ boilerplate >> > > - cleaned up the included files >> > > >> > > Changes since v4: >> > > - new patch. Lee, please bear with me. I didn't want to delay the >> > > new version (where a lot of remarks on the other patches were >> > > addressed) even more, just because we haven't figured out how >> > > to deal with the MFD part. So for now, I've included this one. >> > > >> > > drivers/mfd/Kconfig | 5 ++++ >> > > drivers/mfd/Makefile | 1 + >> > > drivers/mfd/simple-mfd-i2c.c | 55 >> > > ++++++++++++++++++++++++++++++++++++ >> > > 3 files changed, 61 insertions(+) >> > > create mode 100644 drivers/mfd/simple-mfd-i2c.c >> > > >> > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig >> > > index 33df0837ab41..c08539c7a166 100644 >> > > --- a/drivers/mfd/Kconfig >> > > +++ b/drivers/mfd/Kconfig >> > > @@ -1162,6 +1162,11 @@ config MFD_SI476X_CORE >> > > To compile this driver as a module, choose M here: the >> > > module will be called si476x-core. >> > > >> > > +config MFD_SIMPLE_MFD_I2C >> > > + tristate >> > > + depends on I2C >> > > + select REGMAP_I2C >> > >> > Please provide a full help. >> >> See above. >> >> > >> > > config MFD_SM501 >> > > tristate "Silicon Motion SM501" >> > > depends on HAS_DMA >> > > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile >> > > index a60e5f835283..78d24a3e7c9e 100644 >> > > --- a/drivers/mfd/Makefile >> > > +++ b/drivers/mfd/Makefile >> > > @@ -264,3 +264,4 @@ obj-$(CONFIG_MFD_STMFX) += stmfx.o >> > > obj-$(CONFIG_MFD_KHADAS_MCU) += khadas-mcu.o >> > > >> > > obj-$(CONFIG_SGI_MFD_IOC3) += ioc3.o >> > > +obj-$(CONFIG_MFD_SIMPLE_MFD_I2C) += simple-mfd-i2c.o >> > > diff --git a/drivers/mfd/simple-mfd-i2c.c >> > > b/drivers/mfd/simple-mfd-i2c.c >> > > new file mode 100644 >> > > index 000000000000..45090ddad104 >> > > --- /dev/null >> > > +++ b/drivers/mfd/simple-mfd-i2c.c >> > > @@ -0,0 +1,55 @@ >> > > +// SPDX-License-Identifier: GPL-2.0-only >> > > +/* >> > > + * A very simple I2C MFD driver >> > >> > Simple MFD - I2C >> >> ok. >> >> > > + * The driver enumerates its children and registers a common >> > > regmap. Use >> > > + * dev_get_regmap(pdev->dev.parent, NULL) in the child nodes to >> > > fetch that >> > > + * regmap instance. >> > >> > This driver creates a single register map with the intention for it to >> > be shared by all sub-devices. Children can use their parent's device >> > structure (dev.parent) in order reference it. >> >> Should this be appended or should it replace my paragraph? If its the >> latter, >> the "enumeration of the children" is missing. > > If you want to keep that part, try: > > This driver creates a single register map with the intention for it to > be shared by all sub-devices. Children can use their parent's device > structure (dev.parent) in order reference it. > > Once the register map has been successfully initialised, any > sub-devices represented by child nodes in Device Tree will be > subsequently registered. > >> > > + * In the future this driver might be extended to support also >> > > other interfaces >> > > + * like SPI etc. >> > >> > Remove this please. >> >> Why would you remove information about the intention of this driver? >> If >> someone >> looks for a place to implement its SPI/I3C/Slimbus MFD driver this >> might >> come >> in handy. > > By all means put something similar in the commit log, but it has no > place in the driver itself. Besides, if we were to add support for > SPI, it is likely to be a completely separate/unrelated driver.
Why would that be another driver? It would be 90% copy paste with regmap_init_i2c() replaced by regmap_init_spi() and i2c_driver replaced by spi_driver.
But I don't care. I'll remove it.
-michael
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