[PATCH 2/8] mfd: mtk-mmsys: Add mmsys driver

Philipp Zabel
2017-11-23T09:09:05Z

Hi Matthias,

On Tue, 2017-11-14 at 22:41 +0100, Matthias Brugger wrote:
> The MMSYS subsystem includes clocks and drm components.
> This patch adds a MFD device to probe both drivers from the same
> device tree compatible.
>
> Signed-off-by: Matthias Brugger <mbrugger@suse.com>
> ---
> drivers/mfd/Kconfig | 9 +++++
> drivers/mfd/Makefile | 2 ++
> drivers/mfd/mtk-mmsys.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/mfd/mmsys.h | 18 ++++++++++
> 4 files changed, 120 insertions(+)
> create mode 100644 drivers/mfd/mtk-mmsys.c
> create mode 100644 include/linux/mfd/mmsys.h
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index fc5e4fef89d2..3250ce5d205a 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -368,6 +368,15 @@ config MFD_MC13XXX_I2C
> help
> Select this if your MC13xxx is connected via an I2C bus.
>
> +config MFD_MEDIATEK_MMSYS
> + tristate "Mediatek MMSYS interface"
> + select MDF_CORE
> + select REGMAP_MMIO
> + help
> + Select this if you have a MMSYS subsystem in your SoC. The
> + MMSYS subsystem has at least a clock driver part and some
> + DRM components.
> +
> config MFD_MXS_LRADC
> tristate "Freescale i.MX23/i.MX28 LRADC"
> depends on ARCH_MXS || COMPILE_TEST
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 8703ff17998e..d4fc99df784c 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -100,6 +100,8 @@ obj-$(CONFIG_MFD_MC13XXX) += mc13xxx-core.o
> obj-$(CONFIG_MFD_MC13XXX_SPI) += mc13xxx-spi.o
> obj-$(CONFIG_MFD_MC13XXX_I2C) += mc13xxx-i2c.o
>
> +obj-$(CONFIG_MFD_MEDIATEK_MMSYS) += mtk-mmsys.o
> +
> obj-$(CONFIG_MFD_CORE) += mfd-core.o
>
> obj-$(CONFIG_EZX_PCAP) += ezx-pcap.o
> diff --git a/drivers/mfd/mtk-mmsys.c b/drivers/mfd/mtk-mmsys.c
> new file mode 100644
> index 000000000000..102b491aa28f
> --- /dev/null
> +++ b/drivers/mfd/mtk-mmsys.c
> @@ -0,0 +1,91 @@
> +/*
> + * mtk-mmsys.c -- Mediatek MMSYS multi-function driver
> + *
> + * Copyright (c) 2017 Matthias Brugger <matthias.bgg@gmail.com>
> + *
> + * Author: Matthias Brugger <matthias.bgg@gmail.com>
> + *
> + * For licencing details see kernel-base/COPYING
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/mmsys.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +enum {
> + MMSYS_MT2701 = 1,
> +};
> +
> +static const struct mfd_cell mmsys_mt2701_devs[] = {
> + { .name = "clk-mt2701-mm", },
> + { .name = "drm-mt2701-mm", },
> +};
> +
> +static int mmsys_probe(struct platform_device *pdev)
> +{
> + struct mmsys_dev *private;
> + const struct mfd_cell *mmsys_cells;
> + int nr_cells;
> + long id;
> + int ret;
> +
> + id = (long) of_device_get_match_data(&pdev->dev);
> + if (!id) {
> + dev_err(&pdev->dev, "of_device_get match_data() failed\n");
> + return -EINVAL;
> + }
> +
> + switch (id) {
> + case MMSYS_MT2701:
> + mmsys_cells = mmsys_mt2701_devs;
> + nr_cells = ARRAY_SIZE(mmsys_mt2701_devs);
> + break;
> + default:
> + return -ENODEV;
> + }
> +
> + private = devm_kzalloc(&pdev->dev, sizeof(*private), GFP_KERNEL);
> + if (!private)
> + return -ENOMEM;
> +
> + private->dev = &pdev->dev;
> + dev_set_drvdata(private->dev, private);
> +
> + private->of_node = pdev->dev.of_node;

This seems superfluous to me. The of_node can be obtained from the
device, and the device itself is already needed to get to the drvdata.

Instead of

mmsys_private = drv_get_drvdata(pdev->dev.parent);
mmsys_dev = mmsys_private.dev;
mmsys_of_node = mmsys_private.of_node;

couldn't the mfd children just do

mmsys_dev = pdev->dev.parent;
mmsys_of_node = pdev->dev.parent->of_node;

?

> +
> + ret = devm_mfd_add_devices(private->dev, 0, mmsys_cells, nr_cells,
> + NULL, 0, NULL);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to add MFD devices %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +};
> +
> +static const struct of_device_id of_match_mmsys[] = {
> + { .compatible = "mediatek,mt2701-mmsys",
> + .data = (void *) MMSYS_MT2701,
> + },
> + { /* sentinel */ },
> +};
> +
> +static struct platform_driver mmsys_drv = {
> + .probe = mmsys_probe,
> + .driver = {
> + .name = "mediatek-mmysys",
> + .of_match_table = of_match_ptr(of_match_mmsys),
> + },
> +};
> +
> +builtin_platform_driver(mmsys_drv);
> +
> +MODULE_DESCRIPTION("Mediatek MMSYS multi-function driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/mmsys.h b/include/linux/mfd/mmsys.h
> new file mode 100644
> index 000000000000..274b9ee03ada
> --- /dev/null
> +++ b/include/linux/mfd/mmsys.h
> @@ -0,0 +1,18 @@
> +/* Header of MMSYS MFD core driver for Mediatek platforms
> + *
> + * Copyright (c) 2017 Matthias Brugger <matthias.bgg@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it under
> + * the terms of the GNU General Public License version 2 as published by the
> + * Free Software Foundation.
> + */
> +
> +#ifndef __MEDIATEK_MMSYS__H__
> +#define __MEDIATEK_MMSYS__H__
> +
> +struct mmsys_dev {
> + struct device *dev;
> + struct device_node *of_node;
> +};

This wouldn't be needed, then.

regards
Philipp