RE: [PATCH 1/3] remap: Add I3C bus support

[Vitor Soares]

Hi Boris,

From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Date: Tue, Apr 16, 2019 at 07:15:51

> Typo in the subject: s/remap/regmap/
> 
> On Mon, 15 Apr 2019 21:19:39 +0200
> Vitor Soares <vitor.soares@xxxxxxxxxxxx> wrote:
> 
> > Add basic support for I3C bus.
> > This is a simple implementation that only give support
> > for Read and Write commands.
> > 
> > Signed-off-by: Vitor Soares <vitor.soares@xxxxxxxxxxxx>
> > ---
> >  drivers/base/regmap/Kconfig      |  6 +++-
> >  drivers/base/regmap/Makefile     |  1 +
> >  drivers/base/regmap/regmap-i3c.c | 62 ++++++++++++++++++++++++++++++++++++++++
> >  include/linux/regmap.h           | 20 +++++++++++++
> >  4 files changed, 88 insertions(+), 1 deletion(-)
> >  create mode 100644 drivers/base/regmap/regmap-i3c.c
> > 
> > diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
> > index 6ad5ef4..c8bbf53 100644
> > --- a/drivers/base/regmap/Kconfig
> > +++ b/drivers/base/regmap/Kconfig
> > @@ -4,7 +4,7 @@
> >  # subsystems should select the appropriate symbols.
> >  
> >  config REGMAP
> > -	default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_W1 || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ)
> > +	default y if (REGMAP_I2C || REGMAP_SPI || REGMAP_SPMI || REGMAP_W1 || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ || REGMAP_I3C)
> >  	select IRQ_DOMAIN if REGMAP_IRQ
> >  	bool
> >  
> > @@ -49,3 +49,7 @@ config REGMAP_SOUNDWIRE
> >  config REGMAP_SCCB
> >  	tristate
> >  	depends on I2C
> > +
> > +config REGMAP_I3C
> > +	tristate
> > +	depends on I3C
> > diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
> > index f5b4e88..ff6c7d8 100644
> > --- a/drivers/base/regmap/Makefile
> > +++ b/drivers/base/regmap/Makefile
> > @@ -16,3 +16,4 @@ obj-$(CONFIG_REGMAP_IRQ) += regmap-irq.o
> >  obj-$(CONFIG_REGMAP_W1) += regmap-w1.o
> >  obj-$(CONFIG_REGMAP_SOUNDWIRE) += regmap-sdw.o
> >  obj-$(CONFIG_REGMAP_SCCB) += regmap-sccb.o
> > +obj-$(CONFIG_REGMAP_I3C) += regmap-i3c.o
> > diff --git a/drivers/base/regmap/regmap-i3c.c b/drivers/base/regmap/regmap-i3c.c
> > new file mode 100644
> > index 0000000..565997b
> > --- /dev/null
> > +++ b/drivers/base/regmap/regmap-i3c.c
> > @@ -0,0 +1,62 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2018 Synopsys, Inc. and/or its affiliates.
> > + *
> > + * Author: Vitor Soares <vitor.soares@xxxxxxxxxxxx>
> > + */
> > +
> > +#include <linux/regmap.h>
> > +#include <linux/i3c/device.h>
> > +#include <linux/i3c/master.h>
> > +#include <linux/module.h>
> > +
> > +static int regmap_i3c_write(void *context, const void *data, size_t count)
> > +{
> > +	struct device *dev = context;
> > +	struct i3c_device *i3c = dev_to_i3cdev(dev);
> > +	struct i3c_priv_xfer xfers[] = {
> > +		{
> > +			.rnw = false,
> > +			.len = count,
> > +			.data.out = data,
> > +		},
> > +	};
> > +
> > +	return i3c_device_do_priv_xfers(i3c, xfers, 1);
> > +}
> > +
> > +static int regmap_i3c_read(void *context,
> > +			   const void *reg, size_t reg_size,
> > +			   void *val, size_t val_size)
> > +{
> > +	struct device *dev = context;
> > +	struct i3c_device *i3c = dev_to_i3cdev(dev);
> > +	struct i3c_priv_xfer xfers[2];
> > +
> > +	xfers[0].rnw = false;
> > +	xfers[0].len = reg_size;
> > +	xfers[0].data.out = reg;
> > +
> > +	xfers[1].rnw = true;
> > +	xfers[1].len = val_size;
> > +	xfers[1].data.in = val;
> > +
> > +	return i3c_device_do_priv_xfers(i3c, xfers, 2);
> > +}
> > +
> > +static struct regmap_bus regmap_i3c = {
> > +	.write = regmap_i3c_write,
> > +	.read = regmap_i3c_read,
> > +};
> > +
> > +struct regmap *__devm_regmap_init_i3c(struct i3c_device *i3c,
> > +				      const struct regmap_config *config,
> > +				      struct lock_class_key *lock_key,
> > +				      const char *lock_name)
> > +{
> > +	return __devm_regmap_init(&i3c->dev, &regmap_i3c, &i3c->dev, config,
> > +				  lock_key, lock_name);
> > +}
> > +EXPORT_SYMBOL_GPL(__devm_regmap_init_i3c);
> > +
> > +MODULE_LICENSE("GPL");
> > diff --git a/include/linux/regmap.h b/include/linux/regmap.h
> > index daeec7d..f65984d 100644
> > --- a/include/linux/regmap.h
> > +++ b/include/linux/regmap.h
> > @@ -25,6 +25,7 @@ struct module;
> >  struct clk;
> >  struct device;
> >  struct i2c_client;
> > +struct i3c_device;
> >  struct irq_domain;
> >  struct slim_device;
> >  struct spi_device;
> > @@ -624,6 +625,10 @@ struct regmap *__devm_regmap_init_slimbus(struct slim_device *slimbus,
> >  				 const struct regmap_config *config,
> >  				 struct lock_class_key *lock_key,
> >  				 const char *lock_name);
> > +struct regmap *__devm_regmap_init_i3c(struct i3c_device *i3c,
> > +				 const struct regmap_config *config,
> > +				 struct lock_class_key *lock_key,
> > +				 const char *lock_name);
> >  /*
> >   * Wrapper for regmap_init macros to include a unique lockdep key and name
> >   * for each call. No-op if CONFIG_LOCKDEP is not set.
> > @@ -982,6 +987,21 @@ bool regmap_ac97_default_volatile(struct device *dev, unsigned int reg);
> >  #define devm_regmap_init_slimbus(slimbus, config)			\
> >  	__regmap_lockdep_wrapper(__devm_regmap_init_slimbus, #config,	\
> >  				slimbus, config)
> > +
> > +/**
> > + * devm_regmap_init_i3c() - Initialise managed register map
> 
> Maybe we should have a more specific name here, as some might want to
> access registers using HDR modes (devm_regmap_init_i3c_sdr()?)

That make sense if the device with HDR capability is able to do 
everything in HDR mode and I'm not sure about that.
I would like to wait for a couple of commercial devices before that 
change.

> 
> 
> > + *
> > + * @i3c: Device that will be interacted with
> > + * @config: Configuration for register map
> > + *
> > + * The return value will be an ERR_PTR() on error or a valid pointer
> > + * to a struct regmap.  The regmap will be automatically freed by the
> > + * device management code.
> > + */
> > +#define devm_regmap_init_i3c(i3c, config)				\
> > +	__regmap_lockdep_wrapper(__devm_regmap_init_i3c, #config,	\
> > +				i3c, config)
> > +
> >  int regmap_mmio_attach_clk(struct regmap *map, struct clk *clk);
> >  void regmap_mmio_detach_clk(struct regmap *map);
> >  void regmap_exit(struct regmap *map);


Thanks for your feedback.

Best regards,
Vitor Soares