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Date:   Tue, 16 Apr 2019 08:15:51 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     Vitor Soares <vitor.soares@synopsys.com>
Cc:     linux-iio@vger.kernel.org, linux-i3c@lists.infradead.org,
        linux-kernel@vger.kernel.org, pmeerw@pmeerw.net, lars@metafoo.de,
        knaack.h@gmx.de, jic23@kernel.org, lorenzo.bianconi83@gmail.com,
        bbrezillon@kernel.org, rafael@kernel.org,
        gregkh@linuxfoundation.org, broonie@kernel.org,
        joao.pinto@synopsys.com
Subject: Re: [PATCH 1/3] remap: Add I3C bus support
Message-ID: <20190416081551.6f21bc38@collabora.com>
In-Reply-To: <c38e3cb9e8524af58c995a9cf1f79ddba69b47b4.1555354268.git.vitor.soares@synopsys.com>
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        <c38e3cb9e8524af58c995a9cf1f79ddba69b47b4.1555354268.git.vitor.soares@synopsys.com>
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Typo in the subject: s/remap/regmap/

On Mon, 15 Apr 2019 21:19:39 +0200
Vitor Soares <vitor.soares@synopsys.com> 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@synopsys.com>
> ---
>  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@synopsys.com>
> + */
> +
> +#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()?)


> + *
> + * @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);