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Date:   Wed, 19 May 2021 12:11:25 +0100
From:   Lee Jones <lee.jones@linaro.org>
To:     Robert Marko <robert.marko@sartura.hr>
Cc:     robh+dt@kernel.org, linus.walleij@linaro.org,
        bgolaszewski@baylibre.com, jdelvare@suse.com, linux@roeck-us.net,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-gpio@vger.kernel.org, linux-hwmon@vger.kernel.org,
        luka.perkov@sartura.hr, jmp@epiphyte.org, pmenzel@molgen.mpg.de,
        buczek@molgen.mpg.de
Subject: Re: [PATCH 1/6] mfd: Add Delta TN48M CPLD driver
Message-ID: <20210519111125.GD2403908@dell>
References: <20210430123511.116057-1-robert.marko@sartura.hr>
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In-Reply-To: <20210430123511.116057-1-robert.marko@sartura.hr>
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On Fri, 30 Apr 2021, Robert Marko wrote:

> Delta TN48M switches have a Lattice CPLD that serves
> multiple purposes including being a GPIO expander.
> So lets add the MFD core driver for it.
> 
> Signed-off-by: Robert Marko <robert.marko@sartura.hr>
> ---
>  drivers/mfd/Kconfig       |  13 +++
>  drivers/mfd/Makefile      |   1 +
>  drivers/mfd/tn48m-cpld.c  | 181 ++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/tn48m.h |  30 +++++++
>  4 files changed, 225 insertions(+)
>  create mode 100644 drivers/mfd/tn48m-cpld.c
>  create mode 100644 include/linux/mfd/tn48m.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index b74efa469e90..809041f98d71 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -297,6 +297,19 @@ config MFD_ASIC3
>  	  This driver supports the ASIC3 multifunction chip found on many
>  	  PDAs (mainly iPAQ and HTC based ones)
>  
> +config MFD_TN48M_CPLD
> +	tristate "Delta Networks TN48M switch CPLD driver"
> +	depends on I2C
> +	select MFD_CORE
> +	select REGMAP_I2C
> +	help
> +	  Select this option to enable support for Delta Networks TN48M switch
> +	  CPLD. It consists of GPIO and hwmon drivers.
> +	  CPLD provides GPIOS-s for the SFP slots as well as power supply
> +	  related information.
> +	  Driver provides debugfs information about the board model as
> +	  well as hardware and CPLD revision information.

No need for every sentence to be it's own paragraphs.

Please re-align to be a single chunk.

>  config PMIC_DA903X
>  	bool "Dialog Semiconductor DA9030/DA9034 PMIC Support"
>  	depends on I2C=y
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 834f5463af28..974663341f08 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -27,6 +27,7 @@ obj-$(CONFIG_MFD_TI_LP87565)	+= lp87565.o
>  obj-$(CONFIG_MFD_DAVINCI_VOICECODEC)	+= davinci_voicecodec.o
>  obj-$(CONFIG_MFD_DM355EVM_MSP)	+= dm355evm_msp.o
>  obj-$(CONFIG_MFD_TI_AM335X_TSCADC)	+= ti_am335x_tscadc.o
> +obj-$(CONFIG_MFD_TN48M_CPLD)	+= tn48m-cpld.o
>  
>  obj-$(CONFIG_MFD_STA2X11)	+= sta2x11-mfd.o
>  obj-$(CONFIG_MFD_STMPE)		+= stmpe.o
> diff --git a/drivers/mfd/tn48m-cpld.c b/drivers/mfd/tn48m-cpld.c
> new file mode 100644
> index 000000000000..b84510fb630a
> --- /dev/null
> +++ b/drivers/mfd/tn48m-cpld.c
> @@ -0,0 +1,181 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Delta TN48M CPLD parent driver
> + *
> + * Copyright 2020 Sartura Ltd

This is out of date.

> + * Author: Robert Marko <robert.marko@sartura.hr>
> + */
> +
> +#include <linux/debugfs.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/tn48m.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +static const struct mfd_cell tn48m_cell[] = {};

Please populate this.

Without it, this is not an MFD.

> +static const struct regmap_config tn48m_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = 0x40,
> +};
> +
> +static int hardware_version_show(struct seq_file *s, void *data)
> +{
> +	struct tn48m_data *priv = s->private;
> +	unsigned int regval;
> +	char *buf;
> +
> +	regmap_read(priv->regmap, HARDWARE_VERSION_ID, &regval);
> +
> +	switch (FIELD_GET(HARDWARE_VERSION_MASK, regval)) {
> +	case HARDWARE_VERSION_EVT1:
> +		buf = "EVT1";
> +		break;
> +	case HARDWARE_VERSION_EVT2:
> +		buf = "EVT2";
> +		break;
> +	case HARDWARE_VERSION_DVT:
> +		buf = "DVT";
> +		break;
> +	case HARDWARE_VERSION_PVT:
> +		buf = "PVT";
> +		break;
> +	default:
> +		buf = "Unknown";
> +		break;
> +	}
> +
> +	seq_printf(s, "%s\n", buf);
> +
> +	return 0;
> +}
> +

Please drop this '\n'.

> +DEFINE_SHOW_ATTRIBUTE(hardware_version);
> +
> +static int board_id_show(struct seq_file *s, void *data)
> +{
> +	struct tn48m_data *priv = s->private;
> +	unsigned int regval;
> +	char *buf;
> +
> +	regmap_read(priv->regmap, BOARD_ID, &regval);
> +
> +	switch (regval) {
> +	case BOARD_ID_TN48M:
> +		buf = "TN48M";
> +		break;
> +	case BOARD_ID_TN48M_P:
> +		buf = "TN48-P";
> +		break;
> +	default:
> +		buf = "Unknown";
> +		break;
> +	}
> +
> +	seq_printf(s, "%s\n", buf);
> +
> +	return 0;
> +}
> +

Please drop this '\n'.

> +DEFINE_SHOW_ATTRIBUTE(board_id);
> +
> +static int code_version_show(struct seq_file *s, void *data)
> +{
> +	struct tn48m_data *priv = s->private;
> +	unsigned int regval;
> +
> +	regmap_read(priv->regmap, CPLD_CODE_VERSION, &regval);
> +
> +	seq_printf(s, "%d\n", regval);
> +
> +	return 0;
> +}
> +

Please drop this '\n'.

> +DEFINE_SHOW_ATTRIBUTE(code_version);
> +
> +static void tn48m_init_debugfs(struct tn48m_data *data)
> +{
> +	data->debugfs_dir = debugfs_create_dir(data->client->name, NULL);
> +
> +	debugfs_create_file("hardware_version",
> +			    0400,
> +			    data->debugfs_dir,
> +			    data,
> +			    &hardware_version_fops);
> +
> +	debugfs_create_file("board_id",
> +			    0400,
> +			    data->debugfs_dir,
> +			    data,
> +			    &board_id_fops);
> +
> +	debugfs_create_file("code_version",
> +			    0400,
> +			    data->debugfs_dir,
> +			    data,
> +			    &code_version_fops);
> +}

Does S/W actually do anything useful with these files?

Or are they just there for the sake of it?

If the latter, just print them to the kernel log and have done.

> +static int tn48m_probe(struct i2c_client *client)
> +{
> +	struct tn48m_data *data;

'ddata' for both please.

> +	int ret;
> +
> +	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->client = client;
> +	data->dev = &client->dev;
> +	i2c_set_clientdata(client, data);
> +
> +	data->regmap = devm_regmap_init_i2c(client, &tn48m_regmap_config);
> +	if (IS_ERR(data->regmap)) {
> +		dev_err(data->dev, "Failed to allocate regmap\n");
> +		return PTR_ERR(data->regmap);
> +	}
> +
> +	ret = devm_mfd_add_devices(data->dev, PLATFORM_DEVID_AUTO, tn48m_cell,
> +				   ARRAY_SIZE(tn48m_cell), NULL, 0, NULL);
> +	if (ret)
> +		dev_err(data->dev, "Failed to register sub-devices %d\n", ret);
> +
> +	tn48m_init_debugfs(data);
> +
> +	return ret;
> +}
> +
> +static int tn48m_remove(struct i2c_client *client)
> +{
> +	struct tn48m_data *data = i2c_get_clientdata(client);
> +
> +	debugfs_remove_recursive(data->debugfs_dir);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id tn48m_of_match[] = {
> +	{ .compatible = "delta,tn48m-cpld"},

Missing ' ' before the '}'.

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, tn48m_of_match);
> +
> +static struct i2c_driver tn48m_driver = {
> +	.driver = {
> +		.name = "tn48m-cpld",
> +		.of_match_table = tn48m_of_match,
> +	},
> +	.probe_new	= tn48m_probe,
> +	.remove		= tn48m_remove,
> +};
> +module_i2c_driver(tn48m_driver);
> +
> +MODULE_AUTHOR("Robert Marko <robert.marko@sartura.hr>");
> +MODULE_DESCRIPTION("Delta TN48M CPLD parent driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/tn48m.h b/include/linux/mfd/tn48m.h
> new file mode 100644
> index 000000000000..551c550efa54
> --- /dev/null
> +++ b/include/linux/mfd/tn48m.h
> @@ -0,0 +1,30 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright 2020 Sartura Ltd

Out of date.

> + */
> +
> +#ifndef __TN48M_H__
> +#define __TN48M_H__

Better prefix with MFD.

> +#include <linux/device.h>
> +#include <linux/regmap.h>
> +
> +#define HARDWARE_VERSION_ID	0x0
> +#define HARDWARE_VERSION_MASK	GENMASK(3, 0)
> +#define HARDWARE_VERSION_EVT1	0
> +#define HARDWARE_VERSION_EVT2	1
> +#define HARDWARE_VERSION_DVT	2
> +#define HARDWARE_VERSION_PVT	3
> +#define BOARD_ID		0x1
> +#define BOARD_ID_TN48M		0xa
> +#define BOARD_ID_TN48M_P	0xb
> +#define CPLD_CODE_VERSION	0x2
> +
> +struct tn48m_data {
> +	struct device *dev;
> +	struct regmap *regmap;
> +	struct i2c_client *client;

You don't need both 'dev' and 'client'.

> +	struct dentry *debugfs_dir;
> +};
> +
> +#endif

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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