linux-kernel - Re: [PATCH v3 3/7] misc: Add cros_ec

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Date:	Fri, 23 Jan 2015 09:27:22 +0530
From:	Varka Bhadram <varkabhadram@...il.com>
To:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Cc:	Lee Jones <lee.jones@...aro.org>, Olof Johansson <olof@...om.net>,
	Arnd Bergmann <arnd@...db.de>,
	Doug Anderson <dianders@...omium.org>,
	Bill Richardson <wfrichar@...omium.org>,
	Simon Glass <sjg@...gle.com>,
	Gwendal Grignou <gwendal@...gle.com>,
	Jonathan Corbet <corbet@....net>,
	linux-samsung-soc@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 3/7] misc: Add cros_ec_lpc driver for x86 devices

On Fri, Jan 23, 2015 at 12:46 AM, Javier Martinez Canillas
<javier.martinez@...labora.co.uk> wrote:
> From: Bill Richardson <wfrichar@...omium.org>
>
> Chromebooks have an Embedded Controller (EC) that is used to
> implement various functions such as keyboard, power and battery.
>
> The AP can communicate with the EC through different bus types
> such as I2C, SPI or LPC.
>
> The cros_ec mfd driver is then composed of a core driver that
> register the sub-devices as mfd cells and provide a high level
> communication interface that is used by the rest of the kernel
> and bus specific interfaces modules.
>
> Each connection method then has its own driver, which register
> with the EC driver interface-agnostic interface.
>
> Currently, there are drivers to communicate with the EC over
> I2C and SPI and this driver adds support for LPC.
>
> Signed-off-by: Bill Richardson <wfrichar@...omium.org>
> Signed-off-by: Javier Martinez Canillas <javier.martinez@...labora.co.uk>
> ---
>
> Changes since v2:
>  - Move out from drivers/mfd to drivers/misc. Suggested by Lee Jones.
>
> Changes since v1: None, new patch.
> ---
>  drivers/misc/Kconfig       |  10 ++
>  drivers/misc/Makefile      |   1 +
>  drivers/misc/cros_ec_lpc.c | 306 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 317 insertions(+)
>  create mode 100644 drivers/misc/cros_ec_lpc.c
(...)
> +static int cros_ec_lpc_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct cros_ec_device *ec_dev;
> +       int err = -ENOTTY;
> +
> +       if (!request_region(EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE, MYNAME)) {

Why dont you use devres API for request_region()... Then maximum of
your goto label regarding
release region will gone...

> +               dev_warn(dev, "couldn't reserve memmap region\n");
> +               goto failed_memmap;
> +       }
> +
> +       if ((inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) != 'E') ||
> +           (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) != 'C')) {
> +               dev_warn(dev, "EC ID not detected\n");
> +               goto failed_ec_probe;
> +       }
> +
> +       if (!request_region(EC_HOST_CMD_REGION0, EC_HOST_CMD_REGION_SIZE,
> +                           MYNAME)) {

same...

> +               dev_warn(dev, "couldn't reserve region0\n");
> +               goto failed_region0;
> +       }
> +       if (!request_region(EC_HOST_CMD_REGION1, EC_HOST_CMD_REGION_SIZE,
> +                           MYNAME)) {

same ...

> +               dev_warn(dev, "couldn't reserve region1\n");
> +               goto failed_region1;
> +       }
> +
> +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> +       if (!ec_dev) {
> +               err = -ENOMEM;
> +               goto failed_ec_dev;
> +       }
> +
> +       platform_set_drvdata(pdev, ec_dev);
> +       ec_dev->dev = dev;
> +       ec_dev->ec_name = pdev->name;
> +       ec_dev->phys_name = dev_name(dev);
> +       ec_dev->parent = dev;
> +       ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc;
> +       ec_dev->cmd_readmem = cros_ec_lpc_readmem;
> +
> +       err = cros_ec_register(ec_dev);
> +       if (err) {
> +               dev_warn(dev, "couldn't register ec_dev\n");
> +               goto failed_ec_dev;
> +       }
> +
> +       return 0;
> +
> +failed_ec_dev:
> +       release_region(EC_HOST_CMD_REGION1, EC_HOST_CMD_REGION_SIZE);
> +failed_region1:
> +       release_region(EC_HOST_CMD_REGION0, EC_HOST_CMD_REGION_SIZE);
> +failed_region0:
> +failed_ec_probe:
> +       release_region(EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE);

All these goto labels will be gone if you use devres API..

> +failed_memmap:
> +       return err;
> +}
> +
> +static int cros_ec_lpc_remove(struct platform_device *pdev)
> +{
> +       struct cros_ec_device *ec_dev;
> +
> +       ec_dev = platform_get_drvdata(pdev);
> +       cros_ec_remove(ec_dev);
> +
> +       release_region(EC_HOST_CMD_REGION1, EC_HOST_CMD_REGION_SIZE);
> +       release_region(EC_HOST_CMD_REGION0, EC_HOST_CMD_REGION_SIZE);
> +       release_region(EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE);
> +

These also will be gone....


-- 
Thanks and Regards,
Varka Bhadram.
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