Re: [PATCH 1/5] memory: add a driver for atmel ram controllers

[Boris BREZILLON <boris.brezillon@free-electrons.com>]

On Mon,  7 Jul 2014 17:19:11 +0200
Alexandre Belloni <alexandre.belloni@free-electrons.com> wrote:

> Atmel SoCs have one or multiple RAM controllers that need one or multiple clocks
> to run.
> This driver handle those clocks.
> 

Actually this controller is an SDRAM controller which, depending on the
SoC, might support SDR SDRAMs, DDR SDRAMs or both.

This is just a nitpick, but if you don't mind I'd rather replace
references to RAMC by SDRAMC (ATMEL_RAMC -> ATMEL_SDRAMC) and just state
that in some cases (at least this is the case for the DDRSDRC available
in at91sam9g45 SoC) it supports both type of SDRAM (DDR and SDR).

The same goes for the source file name (atmel-ramc.c -> atmel-sdramc.c).

> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> ---
>  .../devicetree/bindings/arm/atmel-at91.txt         |  1 +
>  drivers/memory/Kconfig                             |  8 ++
>  drivers/memory/Makefile                            |  1 +
>  drivers/memory/atmel-ramc.c                        | 96 ++++++++++++++++++++++
>  4 files changed, 106 insertions(+)
>  create mode 100644 drivers/memory/atmel-ramc.c
> 
> diff --git a/Documentation/devicetree/bindings/arm/atmel-at91.txt b/Documentation/devicetree/bindings/arm/atmel-at91.txt
> index 16f60b41c147..54dc3aefb12a 100644
> --- a/Documentation/devicetree/bindings/arm/atmel-at91.txt
> +++ b/Documentation/devicetree/bindings/arm/atmel-at91.txt
> @@ -61,6 +61,7 @@ RAMC SDRAM/DDR Controller required properties:
>  - compatible: Should be "atmel,at91rm9200-sdramc",
>  			"atmel,at91sam9260-sdramc",
>  			"atmel,at91sam9g45-ddramc",
> +			"atmel,sama5d3-mpddramc",
>  - reg: Should contain registers location and length
>    For at91sam9263 and at91sam9g45 you must specify 2 entries.

Shouldn't we move the documentation in
Documentation/devicetree/bindings/memory-controllers/ (though this
should be done in different patch).

>  
> diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
> index c59e9c96e86d..e49b9caa1b30 100644
> --- a/drivers/memory/Kconfig
> +++ b/drivers/memory/Kconfig
> @@ -7,6 +7,14 @@ menuconfig MEMORY
>  
>  if MEMORY
>  
> +config ATMEL_RAMC
> +	bool "Atmel (Multi-port DDR-)SDRAM Controller"
> +	default y
> +	depends on ARCH_AT91 && OF
> +	help
> +	  This driver is for Atmel SDRAM Controller or Atmel Multi-port
> +	  DDR-SDRAM Controller available on Atmel AT91SAM9 and SAMA5 SoCs
> +
>  config TI_AEMIF
>  	tristate "Texas Instruments AEMIF driver"
>  	depends on (ARCH_DAVINCI || ARCH_KEYSTONE) && OF
> diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
> index 71160a2b7313..eb5d7716efa4 100644
> --- a/drivers/memory/Makefile
> +++ b/drivers/memory/Makefile
> @@ -5,6 +5,7 @@
>  ifeq ($(CONFIG_DDR),y)
>  obj-$(CONFIG_OF)		+= of_memory.o
>  endif
> +obj-$(CONFIG_ATMEL_RAMC)	+= atmel-ramc.o
>  obj-$(CONFIG_TI_AEMIF)		+= ti-aemif.o
>  obj-$(CONFIG_TI_EMIF)		+= emif.o
>  obj-$(CONFIG_FSL_IFC)		+= fsl_ifc.o
> diff --git a/drivers/memory/atmel-ramc.c b/drivers/memory/atmel-ramc.c
> new file mode 100644
> index 000000000000..1d12d3d01cbd
> --- /dev/null
> +++ b/drivers/memory/atmel-ramc.c
> @@ -0,0 +1,96 @@
> +/*
> + * Atmel (Multi-port DDR-)SDRAM Controller driver
> + *
> + * Copyright (C) 2014 Atmel
> + *
> + * 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 version 2 of the License.
> + *
> + * This program is distributed in the hope that 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +
> +struct at91_ramc_caps {
> +	bool has_ddrck;
> +	bool has_mpddr_clk;
> +};
> +
> +static const struct at91_ramc_caps at91rm9200_caps = { };
> +
> +static const struct at91_ramc_caps at91sam9g45_caps = {
> +	.has_ddrck = 1,
> +	.has_mpddr_clk = 0,
> +};
> +
> +static const struct at91_ramc_caps sama5d3_caps = {
> +	.has_ddrck = 1,
> +	.has_mpddr_clk = 1,
> +};
> +
> +static const struct of_device_id atmel_ramc_of_match[] = {
> +	{ .compatible = "atmel,at91rm9200-sdramc", .data = &at91rm9200_caps, },
> +	{ .compatible = "atmel,at91sam9260-sdramc", .data = &at91rm9200_caps, },
> +	{ .compatible = "atmel,at91sam9g45-ddramc", .data = &at91sam9g45_caps, },
> +	{ .compatible = "atmel,sama5d3-mpddramc", .data = &sama5d3_caps, },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, atmel_ramc_of_match);
> +
> +static int atmel_ramc_probe(struct platform_device *pdev)
> +{
> +	const struct of_device_id *match;
> +	const struct at91_ramc_caps *caps;
> +	struct clk *clk;
> +
> +	match = of_match_device(atmel_ramc_of_match, &pdev->dev);
> +	caps = match->data;
> +
> +	if (caps->has_ddrck) {
> +		clk = devm_clk_get(&pdev->dev, "ddrck");
> +		if (IS_ERR(clk))
> +			return PTR_ERR(clk);
> +		clk_prepare_enable(clk);
> +	}
> +
> +	if (caps->has_mpddr_clk) {
> +		clk = devm_clk_get(&pdev->dev, "mpddr");
> +		if (WARN_ON(IS_ERR(clk)))
> +			return 0;
> +		clk_prepare_enable(clk);
> +	}
> +
> +	return 0;
> +}
> +
> +static struct platform_driver atmel_ramc_driver = {
> +	.probe		= atmel_ramc_probe,
> +	.driver		= {
> +		.name	= "atmel-ramc",
> +		.owner	= THIS_MODULE,
> +		.of_match_table = atmel_ramc_of_match,
> +	},
> +};
> +
> +static int __init atmel_ramc_init(void)
> +{
> +	return platform_driver_register(&atmel_ramc_driver);
> +}
> +module_init(atmel_ramc_init);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
> +MODULE_DESCRIPTION("Atmel (Multi-port DDR-)SDRAM Controller");



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com