[PATCH 06/67] max3110 sanity check a register
in [Kernel]
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From: Greg Kroah-Hartman on 5 Aug 2010 18:30 From: jianwei.yang <jianwei.yang(a)intel.com> MAX3111 is the SPI/UART IC installed on the MRST SPI Port Card as a serial debug goal, and the SPI Port Card will be frequently mounted and unmounted from the main board by developers depending whether debug serial is required or not. As the MAX3111 has no subvendor or product id registers available, the patch will try to access one register to decide if this IC is present or not. Signed-off-by: Alan Cox <alan(a)linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de> --- drivers/serial/mrst_max3110.c | 13 +++++++++++-- 1 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/serial/mrst_max3110.c b/drivers/serial/mrst_max3110.c index 273e7cb..f9c01ae 100644 --- a/drivers/serial/mrst_max3110.c +++ b/drivers/serial/mrst_max3110.c @@ -721,7 +721,7 @@ static int serial_m3110_probe(struct spi_device *spi) struct uart_max3110 *max; int ret; unsigned char *buffer; - + u16 res; max = kzalloc(sizeof(*max), GFP_KERNEL); if (!max) return -ENOMEM; @@ -753,7 +753,16 @@ static int serial_m3110_probe(struct spi_device *spi) max->cur_conf = 0; atomic_set(&max->irq_pending, 0); - + /* Check if reading configuration register returns something sane */ + + res = RC_TAG; + ret = max3110_write_then_read(max, (u8 *)&res, (u8 *)&res, 2, 0); + if (ret < 0 || res == 0 || res == 0xffff) { + printk(KERN_ERR "MAX3111 deemed not present (conf reg %04x)", + res); + ret = -ENODEV; + goto err_get_page; + } buffer = (unsigned char *)__get_free_page(GFP_KERNEL); if (!buffer) { ret = -ENOMEM; -- 1.7.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |