Re: [patch v4 2/2] mfd: Add Mellanox regmap I2C driver

[Lee Jones <lee.jones@linaro.org>]

On Tue, 29 Aug 2017, Vadim Pasternak wrote:

> This patch adds I2C regmap driver for Mellanox BMC cards with the
> programmable devices attached to I2C interface. It allows support
> for CPLD devices with one and two bytes address space.
> 
> Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
> Acked-by: Pavel Machek <pavel@ucw.cz>
> ---
>  MAINTAINERS              |   1 +
>  drivers/mfd/Kconfig      |  13 ++++
>  drivers/mfd/Makefile     |   1 +
>  drivers/mfd/mlxreg-i2c.c | 183 +++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 198 insertions(+)
>  create mode 100644 drivers/mfd/mlxreg-i2c.c

I don't know what this is, but it is not an MFD driver.  Please find
somewhere more appropriate to locate it.  MFD is not a dumping ground
for drivers which do not fit anywhere else.

> diff --git a/MAINTAINERS b/MAINTAINERS
> index bcb7f45..86a5f8f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -8299,6 +8299,7 @@ M:	Vadim Pasternak <vadimp@mellanox.com>
>  S:	Supported
>  F:	Documentation/devicetree/bindings/mfd/mellanox,mlxreg-core
>  F:	drivers/mfd/mlxreg-core.c
> +F:	drivers/mfd/mlxreg-i2c.c
>  F:	include/linux/platform_data/mlxreg.h
>  
>  MELLANOX ETHERNET DRIVER (mlx4_en)
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index fa1562f..453afcb 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1709,6 +1709,19 @@ config MFD_MLXREG_CORE
>  	  This driver can also be built as a module. If so the module
>  	  will be called mlxreg-core.
>  
> +config MFD_MLXREG_I2C
> +	bool "Mellanox programmable device with I2C interface"
> +	depends on I2C && REGMAP_I2C
> +	depends on MFD_MLXREG_CORE
> +	help
> +	  Support for the Mellanox BMC card with hardware control by a
> +	  programmable device. This option enables core support for the
> +	  programmable devices with I2C interface. It allows support for
> +	  the devices with address space 1 and 2 bytes.
> +
> +	  This driver can also be built as a module. If so the module
> +	  will be called mlxreg-i2c.
> +
>  menu "Multimedia Capabilities Port drivers"
>  	depends on ARCH_SA1100
>  
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 9661ee2..b76c5b2 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -222,3 +222,4 @@ obj-$(CONFIG_MFD_SUN4I_GPADC)	+= sun4i-gpadc.o
>  obj-$(CONFIG_MFD_STM32_TIMERS) 	+= stm32-timers.o
>  obj-$(CONFIG_MFD_MXS_LRADC)     += mxs-lradc.o
>  obj-$(CONFIG_MFD_MLXREG_CORE)	+= mlxreg-core.o
> +obj-$(CONFIG_MFD_MLXREG_I2C)	+= mlxreg-i2c.o
> diff --git a/drivers/mfd/mlxreg-i2c.c b/drivers/mfd/mlxreg-i2c.c
> new file mode 100644
> index 0000000..04823b5
> --- /dev/null
> +++ b/drivers/mfd/mlxreg-i2c.c
> @@ -0,0 +1,183 @@
> +/*
> + * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
> + * Copyright (c) 2017 Vadim Pasternak <vadimp@mellanox.com>
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions are met:
> + *
> + * 1. Redistributions of source code must retain the above copyright
> + *    notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + *    notice, this list of conditions and the following disclaimer in the
> + *    documentation and/or other materials provided with the distribution.
> + * 3. Neither the names of the copyright holders nor the names of its
> + *    contributors may be used to endorse or promote products derived from
> + *    this software without specific prior written permission.
> + *
> + * Alternatively, this software may be distributed under the terms of the
> + * GNU General Public License ("GPL") version 2 as published by the Free
> + * Software Foundation.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
> + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
> + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
> + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
> + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
> + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
> + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
> + * POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +/**
> + * enum mlxreg_i2c_type - driver flavours:
> + *
> + * @MLXREG_8BIT: type for I2C CPLD control with 1 byte address space;
> + * @MLXREG_16BIT: type for I2C CPLD control with 2 bytes address space;
> + */
> +enum mlxreg_i2c_type {
> +	MLXREG_8BIT,
> +	MLXREG_16BIT,
> +};
> +
> +/**
> + * Configuration for the register map of a device with 1 byte address space.
> + */
> +static const struct regmap_config mlxreg_i2c_regmap8_conf = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = 255,
> +};
> +
> +/**
> + * Configuration for the register map of a device with 2 bytes address space.
> + */
> +static const struct regmap_config mlxreg_i2c_regmap16_conf = {
> +	.reg_bits = 16,
> +	.val_bits = 16,
> +	.max_register = 1023,
> +};
> +
> +static struct resource mlxreg_i2c_resources[] = {
> +	[0] = DEFINE_RES_IRQ_NAMED(-1, "mlxcpld-ctrl-2c"),
> +};
> +
> +static int
> +mlxreg_i2c_probe(struct i2c_client *client, const struct i2c_device_id *id)
> +{
> +	struct device_node *child, *np = client->dev.of_node;
> +	struct platform_device *pdev;
> +	struct i2c_adapter *adapter;
> +	struct regmap *regmap;
> +	int err = 0;
> +
> +	if (!np)
> +		return -ENODEV;
> +
> +	if (!of_device_is_compatible(np, "mellanox,mlxreg-i2c"))
> +		return -ENODEV;
> +
> +	child = of_parse_phandle(np, "deferred", 0);
> +	if (child) {
> +		adapter = of_find_i2c_adapter_by_node(child);
> +		of_node_put(child);
> +		if (!adapter)
> +			return -EPROBE_DEFER;
> +	}
> +
> +	if (!i2c_check_functionality(client->adapter,
> +				     I2C_FUNC_SMBUS_BYTE_DATA |
> +				     I2C_FUNC_SMBUS_WORD_DATA |
> +				     I2C_FUNC_SMBUS_I2C_BLOCK))
> +		return -ENODEV;
> +
> +	switch (id->driver_data) {
> +	case MLXREG_8BIT:
> +		regmap = devm_regmap_init_i2c(client,
> +					      &mlxreg_i2c_regmap8_conf);
> +		break;
> +	case MLXREG_16BIT:
> +		regmap = devm_regmap_init_i2c(client,
> +					      &mlxreg_i2c_regmap16_conf);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	pdev = platform_device_alloc("mlxreg-core", (client->adapter->nr << 8)
> +				     | client->addr);
> +	if (!pdev)
> +		return -ENOMEM;
> +
> +	i2c_set_clientdata(client, pdev);
> +	pdev->dev.parent = &client->dev;
> +	pdev->dev.of_node = client->dev.of_node;
> +	pdev->dev.platform_data = regmap;
> +
> +	if (client->irq) {
> +		mlxreg_i2c_resources[0].start = client->irq;
> +		err = platform_device_add_resources(pdev,
> +				mlxreg_i2c_resources,
> +				ARRAY_SIZE(mlxreg_i2c_resources));
> +	}
> +
> +	err = err ? err : platform_device_add(pdev);
> +
> +	if (err)
> +		platform_device_put(pdev);
> +
> +	return err;
> +}
> +
> +static int mlxreg_i2c_remove(struct i2c_client *client)
> +{
> +	struct platform_device *pdev = i2c_get_clientdata(client);
> +
> +	platform_device_unregister(pdev);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id mlxreg_i2c_id[] = {
> +	{ "mlxreg-i2c", MLXREG_8BIT },
> +	{ "mlxreg-i2c-16", MLXREG_16BIT },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(i2c, mlxreg_i2c_id);
> +
> +static const struct of_device_id mlxreg_i2c_dt_match[] = {
> +	{ .compatible = "mellanox,mlxreg-i2c" },
> +	{ .compatible = "mellanox,mlxreg-i2c-16" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, mlxreg_i2c_dt_match);
> +
> +static struct i2c_driver mlxreg_i2c_driver = {
> +	.class = I2C_CLASS_HWMON,
> +	.driver = {
> +	    .name = "mlxreg-i2c",
> +	    .of_match_table = of_match_ptr(mlxreg_i2c_dt_match),
> +	},
> +	.probe = mlxreg_i2c_probe,
> +	.remove = mlxreg_i2c_remove,
> +	.id_table = mlxreg_i2c_id,
> +};
> +
> +module_i2c_driver(mlxreg_i2c_driver);
> +
> +MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
> +MODULE_DESCRIPTION("Mellanox CPLD control I2C driver");
> +MODULE_LICENSE("Dual BSD/GPL");
> +MODULE_ALIAS("mlxreg-i2c");

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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