Re: [PATCH v3 01/36] mtd: st_spi_fsm: Allocate resources and register with MTD framework

srinivas kandagatla
2013-12-02T13:58:58Z

On 29/11/13 12:18, Lee Jones wrote:
> This is a new driver. It's used to communicate with a special type of
> optimised Serial Flash Controller called the FSM. The FSM uses a subset
> of the SPI protocol to communicate with supported NOR-Flash devices.
>
You might want to expand what is FSM here..(Fast sequence mode).
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
> drivers/mtd/devices/Kconfig | 7 +++
> drivers/mtd/devices/Makefile | 1 +
> drivers/mtd/devices/st_spi_fsm.c | 111 +++++++++++++++++++++++++++++++++++++++
> drivers/mtd/devices/st_spi_fsm.h | 27 ++++++++++
> 4 files changed, 146 insertions(+)
> create mode 100644 drivers/mtd/devices/st_spi_fsm.c
> create mode 100644 drivers/mtd/devices/st_spi_fsm.h
>
> diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
> index 74ab4b7..d977281 100644
> --- a/drivers/mtd/devices/Kconfig
> +++ b/drivers/mtd/devices/Kconfig
> @@ -217,6 +217,13 @@ config MTD_DOCG3
> M-Systems and now Sandisk. The support is very experimental,
> and doesn't give access to any write operations.
>
> +config MTD_ST_SPI_FSM
> + tristate "ST Microelectronics SPI FSM Serial Flash Controller"

I think this should depend on ARCH_STI, so that it is not build for x86
or any other platforms.

> + help
> + This provides an MTD device driver for the ST Microelectronics
> + SPI FSM Serial Flash Controller and support for a subset of
> + connected Serial Flash devices.
> +
> if MTD_DOCG3
> config BCH_CONST_M
> default 14
> diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
> index d83bd73..c68868f 100644
> --- a/drivers/mtd/devices/Makefile
> +++ b/drivers/mtd/devices/Makefile
> @@ -16,6 +16,7 @@ obj-$(CONFIG_MTD_NAND_OMAP_BCH) += elm.o
> obj-$(CONFIG_MTD_SPEAR_SMI) += spear_smi.o
> obj-$(CONFIG_MTD_SST25L) += sst25l.o
> obj-$(CONFIG_MTD_BCM47XXSFLASH) += bcm47xxsflash.o
> +obj-$(CONFIG_MTD_ST_SPI_FSM) += st_spi_fsm.o
>
>
> CFLAGS_docg3.o += -I$(src)
> diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c
> new file mode 100644
> index 0000000..1e3abde
> --- /dev/null
> +++ b/drivers/mtd/devices/st_spi_fsm.c
> @@ -0,0 +1,111 @@
> +/*
> + * st_spi_fsm.c Support for ST Serial Flash Controller
> + *
> + * Author: Angus Clark <angus.clark@st.com>
> + *
> + * Copyright (C) 2010-2013 STicroelectronics Limited
> + *
> + * JEDEC probe based on drivers/mtd/devices/m25p80.c
> + *
> + * This code 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.
> + *
> + */
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/sched.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +
> +#include <asm/io.h>
Are you sure about including this?
> +
> +#include "st_spi_fsm.h"
Header file can be removed totally, as this is the only file which is
using it.
> +
> +static int stfsm_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct resource *res;
> + struct stfsm *fsm;
> +
> + if (!np) {
> + dev_err(&pdev->dev, "No DT found\n");
> + return -EINVAL;
> + }
> +
> + fsm = devm_kzalloc(&pdev->dev, sizeof(*fsm), GFP_KERNEL);
> + if (!fsm)
> + return -ENOMEM;
> +
> + fsm->dev = &pdev->dev;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(&pdev->dev, "Resource not found\n");
> + return -ENODEV;
> + }
> +
> + fsm->region = devm_request_mem_region(&pdev->dev, res->start,
> + resource_size(res), pdev->name);
> + if (!fsm->region) {
> + dev_err(&pdev->dev,
> + "Failed to reserve memory region [0x%08x-0x%08x]\n",
> + res->start, res->end);
> + return -EBUSY;
> + }
> +
> + fsm->base = devm_ioremap_nocache(&pdev->dev,
> + res->start, resource_size(res));
> + if (!fsm->base) {
> + dev_err(&pdev->dev, "Failed to ioremap [0x%08x]\n", res->start);
> + return -EINVAL;
> + }
> +
> + mutex_init(&fsm->lock);
> +
> + platform_set_drvdata(pdev, fsm);
> +
> + fsm->mtd.dev.parent = &pdev->dev;
> + fsm->mtd.type = MTD_NORFLASH;
> + fsm->mtd.writesize = 4;
> + fsm->mtd.writebufsize = fsm->mtd.writesize;
> + fsm->mtd.flags = MTD_CAP_NORFLASH;
> +
> + return mtd_device_parse_register(&fsm->mtd, NULL, NULL, NULL, 0);
> +}
> +
> +static int stfsm_remove(struct platform_device *pdev)
> +{
> + struct stfsm *fsm = platform_get_drvdata(pdev);
> + int err;
> +
> + err = mtd_device_unregister(&fsm->mtd);
> + if (err)
> + return err;
> +
> + return 0;
> +}
> +Any reason not to use of_match_ptr macro here?

Thanks,
srini

> +static struct of_device_id stfsm_match[] = {
> + { .compatible = "st,spi-fsm", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, spi_fsm_match);
> +
> +static struct platform_driver stfsm_driver = {
> + .probe = stfsm_probe,
> + .remove = stfsm_remove,
> + .driver = {
> + .name = "st-spi-fsm",
> + .owner = THIS_MODULE,
> + .of_match_table = stfsm_match,
Any reason not to use of_match_ptr macro here?

Thanks,
srini