Re: [PATCH v2 2/5] mfd: ts4800-syscon: add driver for TS-4800 syscon

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

On Thu, 29 Oct 2015, Damien Riegel wrote:

> Driver for TS-4800 syscon. These registers belong to a FPGA that is
> memory mapped and are used for counters, enable various IPs in the FPGA,
> control LEDs, control IOs, etc.
> 
> Currently, only the watchdog is handled.

Why do you require your own syscon driver?

What's wrong with the generic one?

> Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
> ---
>  .../devicetree/bindings/mfd/ts4800-syscon.txt      | 12 ++++

Separate patch please.

>  drivers/mfd/Kconfig                                |  7 ++
>  drivers/mfd/Makefile                               |  1 +
>  drivers/mfd/ts4800-syscon.c                        | 84 ++++++++++++++++++++++
>  include/linux/mfd/ts4800-syscon.h                  | 24 +++++++
>  5 files changed, 128 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mfd/ts4800-syscon.txt
>  create mode 100644 drivers/mfd/ts4800-syscon.c
>  create mode 100644 include/linux/mfd/ts4800-syscon.h
> 
> diff --git a/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt b/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt
> new file mode 100644
> index 0000000..8dbc12c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt
> @@ -0,0 +1,12 @@
> +Technologic Systems Syscon
> +
> +Required properties:
> +- compatible : must be "ts,ts4800-syscon"
> +- reg : physical base address and length of memory mapped region
> +
> +Example:
> +
> +syscon@b0010000 {
> +	compatible = "ts,ts4800-syscon";
> +	reg = <0xb0010000 0x3d>;
> +};
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 3f68dd2..8f03dce 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1302,6 +1302,13 @@ config MFD_TC6393XB
>  	help
>  	  Support for Toshiba Mobile IO Controller TC6393XB
>  
> +config MFD_TS4800_SYSCON
> +	tristate "TS-4800 Syscon Support"
> +	select REGMAP
> +	select REGMAP_MMIO
> +	help
> +	  Support for TS-4800's FPGA Syscon registers
> +
>  config MFD_VX855
>  	tristate "VIA VX855/VX875 integrated south bridge"
>  	depends on PCI
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index ea40e07..e2c0f1b 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -181,6 +181,7 @@ obj-$(CONFIG_MFD_HI6421_PMIC)	+= hi6421-pmic-core.o
>  obj-$(CONFIG_MFD_DLN2)		+= dln2.o
>  obj-$(CONFIG_MFD_RT5033)	+= rt5033.o
>  obj-$(CONFIG_MFD_SKY81452)	+= sky81452.o
> +obj-$(CONFIG_MFD_TS4800_SYSCON)	+= ts4800-syscon.o
>  
>  intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
>  obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o
> diff --git a/drivers/mfd/ts4800-syscon.c b/drivers/mfd/ts4800-syscon.c
> new file mode 100644
> index 0000000..1e42e96
> --- /dev/null
> +++ b/drivers/mfd/ts4800-syscon.c
> @@ -0,0 +1,84 @@
> +/*
> + * Device driver for TS-4800 FPGA's syscon
> + *
> + * Copyright (c) 2015 - Savoir-faire Linux
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.

Why is the MFD v2+ and the Watchdog driver only v2?

> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/mfd/core.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/mfd/ts4800-syscon.h>

Alphabetical.

> +
> +

Superfluous '\n'.

> +static const struct regmap_config ts4800_regmap_config = {
> +	.reg_bits = 32,
> +	.reg_stride = 2,
> +	.val_bits = 16,
> +};
> +
> +static int ts4800_syscon_probe(struct platform_device *pdev)
> +{
> +	struct ts4800_syscon *syscon;
> +	struct resource *res;
> +	void __iomem *base;
> +
> +	syscon = devm_kzalloc(&pdev->dev, sizeof(*syscon), GFP_KERNEL);
> +	if (!syscon)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	syscon->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
> +						   &ts4800_regmap_config);
> +	if (IS_ERR(syscon->regmap)) {
> +		dev_err(&pdev->dev,
> +			"regmap init failed: %ld\n",
> +			PTR_ERR(syscon->regmap));
> +		return PTR_ERR(syscon->regmap);
> +	}
> +
> +	platform_set_drvdata(pdev, syscon);
> +
> +	return 0;
> +}
> +
> +static int ts4800_syscon_remove(struct platform_device *pdev)
> +{
> +	return 0;
> +}

If it doesn't do anything, don't provide it.

> +static const struct of_device_id ts4800_syscon_of_match[] = {
> +	{ .compatible = "ts,ts4800-syscon", },
> +	{ },
> +};
> +
> +static struct platform_driver ts4800_syscon_driver = {
> +	.driver = {
> +		.name	= "ts4800_syscon",
> +		.of_match_table = ts4800_syscon_of_match,
> +	},
> +	.probe	= ts4800_syscon_probe,
> +	.remove	= ts4800_syscon_remove,
> +};
> +module_platform_driver(ts4800_syscon_driver);
> +
> +MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
> +MODULE_DESCRIPTION("TS-4800 Syscon driver");
> +MODULE_LICENSE("GPL v2");

This does not match the header.

> diff --git a/include/linux/mfd/ts4800-syscon.h b/include/linux/mfd/ts4800-syscon.h
> new file mode 100644
> index 0000000..3d29184
> --- /dev/null
> +++ b/include/linux/mfd/ts4800-syscon.h
> @@ -0,0 +1,24 @@
> +/*
> + * Copyright (c) 2015 - Savoir-faire Linux
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +
> +#ifndef __LINUX_MFD_TS4800_SYSCON_H
> +#define __LINUX_MFD_TS4800_SYSCON_H
> +
> +#include <linux/regmap.h>
> +
> +struct ts4800_syscon {
> +	struct regmap		*regmap;
> +};
> +
> +#endif /* __LINUX_MFD_TS4800_SYSCON_H */

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