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Date: Mon, 1 Dec 2014 14:51:16 +0100
From: Linus Walleij <linus.walleij@...aro.org>
To: Muthu Mani <muth@...ress.com>
Cc: Samuel Ortiz <sameo@...ux.intel.com>,
Lee Jones <lee.jones@...aro.org>,
Wolfram Sang <wsa@...-dreams.de>,
Alexandre Courbot <gnurou@...il.com>,
Johan Hovold <johan@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
Rajaram Regupathy <rera@...ress.com>
Subject: Re: [PATCH v4 3/3] gpio: add support for Cypress CYUSBS234 USB-GPIO adapter
On Fri, Nov 28, 2014 at 5:41 PM, Muthu Mani <muth@...ress.com> wrote:
> Adds support for USB-GPIO interface of Cypress Semiconductor
> CYUSBS234 USB-Serial Bridge controller.
>
> The GPIO get/set can be done through vendor command on control endpoint
> for the configured gpios.
>
> Details about the device can be found at:
> http://www.cypress.com/?rID=84126
>
> Signed-off-by: Muthu Mani <muth@...ress.com>
> Signed-off-by: Rajaram Regupathy <rera@...ress.com>
> ---
> Changes since v3:
(..)
> +config GPIO_CYUSBS23X
> + tristate "CYUSBS23x GPIO support"
> + depends on MFD_CYUSBS23X && USB
Doesn't MFD_CYUSV23X already depend on USB?
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +
> +#include <linux/usb.h>
> +#include <linux/gpio.h>
> +
> +#include <linux/mfd/cyusbs23x.h>
Why this arbitrary newlines? Add this
#include <linus/bitops.h>
> +struct cyusbs_gpio {
> + struct gpio_chip gpio;
> + struct cyusbs23x *cyusbs;
> + u32 out_gpio;
> + u32 out_value;
> + u32 in_gpio;
> +};
Add kerneldoc to this struct so we know what the out/in etc are.
> +static int cy_gpio_get(struct gpio_chip *chip,
> + unsigned offset)
> +{
> + int ret;
> + char *buf;
> + u16 wIndex, wValue;
> + struct cyusbs_gpio *gpio = to_cyusbs_gpio(chip);
> + struct cyusbs23x *cyusbs = gpio->cyusbs;
> +
> + if (gpio->out_gpio & (1 << offset))
> + return gpio->out_value & (1 << offset);
Rewrite like this:
if (gpio->out_gpio & BIT(offset))
return !!(gpio->out_value & BIT(offset));
(!! will clamp to [0,1])
> + wValue = offset;
> + wIndex = 0;
> + buf = kmalloc(CY_GPIO_GET_LEN, GFP_KERNEL);
> + if (buf == NULL)
> + return -ENOMEM;
> +
> + ret = usb_control_msg(cyusbs->usb_dev,
> + usb_rcvctrlpipe(cyusbs->usb_dev, 0),
> + CY_GPIO_GET_VALUE_CMD,
> + USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
> + wValue, wIndex, buf, CY_GPIO_GET_LEN,
> + CY_USBS_CTRL_XFER_TIMEOUT);
> + if (ret == CY_GPIO_GET_LEN) {
> + dev_dbg(chip->dev, "%s: offset=%d %02X %02X\n",
> + __func__, offset, buf[0], buf[1]);
> + if (buf[0] == 0)
> + ret = buf[1];
ret = !!buf[1];
> + else
> + ret = -EIO;
> + } else {
> + dev_err(chip->dev, "%s: offset=%d %d\n", __func__, offset, ret);
> + ret = -EIO;
> + }
> +
> + kfree(buf);
> + return ret;
> +}
> +
> +static void cy_gpio_set(struct gpio_chip *chip,
> + unsigned offset, int value)
> +{
> + int ret;
> + u16 wIndex, wValue;
> + struct cyusbs_gpio *gpio = to_cyusbs_gpio(chip);
> + struct cyusbs23x *cyusbs = gpio->cyusbs;
> +
> + wValue = offset;
> + wIndex = value;
> +
> + ret = usb_control_msg(cyusbs->usb_dev,
> + usb_sndctrlpipe(cyusbs->usb_dev, 0),
> + CY_GPIO_SET_VALUE_CMD,
> + USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
> + wValue, wIndex, NULL, 0, CY_USBS_CTRL_XFER_TIMEOUT);
> + if (ret < 0)
> + dev_err(chip->dev, "error setting gpio %d: %d\n", offset, ret);
> + else {
> + if (value)
> + gpio->out_value |= (1 << offset);
> + else
> + gpio->out_value &= ~(1 << offset);
Use the BIT(offset) pattern here and everywhere else in the file.
> +static int cy_get_device_config(struct cyusbs23x *cyusbs, u8 *buf)
> +{
> + int ret;
> +
> + ret = usb_control_msg(cyusbs->usb_dev,
> + usb_sndctrlpipe(cyusbs->usb_dev, 0),
> + CY_DEV_ENABLE_CONFIG_READ_CMD,
> + USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
> + 0xA6BC, 0xB1B0, NULL, 0,
Aren't these 16bit numbers #defined somewhere?
#define CYUSB_VID 0xA6BC and use that?
> +static int cy_gpio_retrieve_gpio_details(struct cyusbs_gpio *gpio)
> +{
> + int ret;
> + u32 drive0, drive1;
> + u8 *buf;
> + struct cyusbs23x *cyusbs = gpio->cyusbs;
> +
> + buf = kzalloc(CY_DEVICE_CONFIG_SIZE, GFP_KERNEL);
> + if (buf == NULL)
> + return -ENOMEM;
> +
> + ret = cy_get_device_config(cyusbs, buf);
> + if (ret) {
> + dev_err(&cyusbs->usb_dev->dev,
> + "could not retrieve device configuration\n");
> + goto error;
> + }
> +
> + /* Retrieve the GPIO configuration details */
> + drive0 = *((u32 *)&buf[436]);
> + drive1 = *((u32 *)&buf[440]);
> + gpio->out_gpio = drive0 | drive1;
> + gpio->out_value = drive1;
> + gpio->in_gpio = *((u32 *)&buf[444]);
These offsets seem horribly arbitrary. Is there a spec of the packet
format to reference in that comment?
Yours,
Linus Walleij
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