我现在研究spi驱动，在2.6.29内核里，有一个问题想问你，就是
    /* setup any gpio we can */

    if (!pdata->set_cs) {
        if (pdata->pin_cs < 0) {
            dev_err(&pdev->dev, "No chipselect pin\n");
            goto err_register;
        }

        err = gpio_request(pdata->pin_cs, dev_name(&pdev->dev));
        if (err) {
            dev_err(&pdev->dev, "Failed to get gpio for cs\n");
            goto err_register;
        }

        hw->set_cs = s3c24xx_spi_gpiocs;
        gpio_direction_output(pdata->pin_cs, 1);
    } else
        hw->set_cs = pdata->set_cs;

上面代码是不是设置片选呢？为什么我设置的不对（我的不是三星的芯片），快崩溃了，望回复！！感激不尽

我板子上电时的错误：
<3>s3c2410-spi s3c2410-spi.0: Failed to get gpio for cs
s3c2410-spi s3c2410-spi.0: Failed to get gpio for cs
<4>s3c2410-spi: probe of s3c2410-spi.0 failed with error -38
s3c2410-spi: probe of s3c2410-spi.0 failed with error -38

为什么会失败呢？？？怎么解决？？望指点。。。
如果我上面得if里的注释掉，会有部分乱码，但别的都对。也能注册。。好奇怪

err = gpio_request(pdata->pin_cs, dev_name(&pdev->dev));
        if (err) {
            dev_err(&pdev->dev, "Failed to get gpio for cs\n");
            goto err_register;
        }

代码就在那里，看不懂吗？

恩，你知道 gpio_request调用的是什么吗？？为什么没调用gpiolib.c下的呢？？？？通过跟踪，调用的是linux/include/gpio.h里的static inline int gpio_request(unsigned gpio, const char *label)
{
    return -ENOSYS;
}
这个好像不对啊？？？？为什么？？

如果你的内核用的是这个gpio_request()，说明内核配置不支持generic gpio，查你用的内核配置里是否有CONFIG_GENERIC_GPIO

内核里看了，
# CONFIG_GENERIC_GPIO is not set
我用的是27的内核，29的spi驱动，是不是不支持呢？？

对于S3C24xx来说，2.6.27的内核就可以支持generic gpio，配置内核的时候选中“GPIO Support”这个选项就可以了。

版主，请问怎么测试spi？看到网上说是
内核编译完成后进入/root/linux-2.6.27/Documentation/spi
执行：arm-linux-gcc -I/root/linux-2.6.27/include  spidev_test.c
后会生成a.out的spi测试程序；
我执行后报错啊？？

[root@localhost spi]# arm-linux-gcc -I/root/linux-2.6.27/include  spidev_test.c
spidev_test.c:22:30: linux/spi/spidev.h: No such file or directory
spidev_test.c: In function `transfer':
spidev_test.c:51: error: variable `tr' has initializer but incomplete type
spidev_test.c:52: error: unknown field `tx_buf' specified in initializer
spidev_test.c:52: warning: excess elements in struct initializer
spidev_test.c:52: warning: (near initialization for `tr')
spidev_test.c:53: error: unknown field `rx_buf' specified in initializer
spidev_test.c:53: warning: excess elements in struct initializer
spidev_test.c:53: warning: (near initialization for `tr')
spidev_test.c:54: error: unknown field `len' specified in initializer
spidev_test.c:54: warning: excess elements in struct initializer
spidev_test.c:54: warning: (near initialization for `tr')
spidev_test.c:55: error: unknown field `delay_usecs' specified in initializer
spidev_test.c:55: warning: excess elements in struct initializer
spidev_test.c:55: warning: (near initialization for `tr')
spidev_test.c:56: error: unknown field `speed_hz' specified in initializer
spidev_test.c:56: warning: excess elements in struct initializer
spidev_test.c:56: warning: (near initialization for `tr')
spidev_test.c:57: error: unknown field `bits_per_word' specified in initializer
spidev_test.c:57: warning: excess elements in struct initializer
spidev_test.c:57: warning: (near initialization for `tr')
spidev_test.c:51: error: storage size of 'tr' isn't known
spidev_test.c: In function `parse_opts':
spidev_test.c:125: error: `SPI_LOOP' undeclared (first use in this function)
spidev_test.c:125: error: (Each undeclared identifier is reported only once
spidev_test.c:125: error: for each function it appears in.)
spidev_test.c:128: error: `SPI_CPHA' undeclared (first use in this function)
spidev_test.c:131: error: `SPI_CPOL' undeclared (first use in this function)
spidev_test.c:134: error: `SPI_LSB_FIRST' undeclared (first use in this function)
spidev_test.c:137: error: `SPI_CS_HIGH' undeclared (first use in this function)
spidev_test.c:140: error: `SPI_3WIRE' undeclared (first use in this function)
spidev_test.c: In function `main':
spidev_test.c:163: error: `SPI_IOC_WR_MODE' undeclared (first use in this function)
spidev_test.c:167: error: `SPI_IOC_RD_MODE' undeclared (first use in this function)
spidev_test.c:174: error: `SPI_IOC_WR_BITS_PER_WORD' undeclared (first use in this function)
spidev_test.c:178: error: `SPI_IOC_RD_BITS_PER_WORD' undeclared (first use in this function)
spidev_test.c:185: error: `SPI_IOC_WR_MAX_SPEED_HZ' undeclared (first use in this function)
spidev_test.c:189: error: `SPI_IOC_RD_MAX_SPEED_HZ' undeclared (first use in this function)
[root@localhost spi]#
什么原因？？怎么解决？？

我在linux/spi/spidev.h 有这个文件啊？？？好奇怪啊？？哪里需要配置？

[root@localhost spi]# arm-linux-gcc -I/root/linux-2.6.27/include  spidev_test.c
spidev_test.c:22:30: linux/spi/spidev.h: No such file or directory

执行"ls -l /root/linux-2.6.27/include/linux/spi/spidev.h"看看

呵呵，问题又神奇的解决了？
http://aiothome.net/read.php?tid-5591-page-e.html#a