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serial: 8250_pci: Add WCH CH352 quirk to avoid Xscale detection

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The code in 8250.c for detecting ARM/XScale UARTs says:

  * Try writing and reading the UART_IER_UUE bit (b6).
  * If it works, this is probably one of the Xscale platform's
  * internal UARTs.

If the above passes, it then goes on to:

     * It's an Xscale.
     * We'll leave the UART_IER_UUE bit set to 1 (enabled).

However, the CH352 uses the UART_IER_UUE as the LOWPOWER function,
so it is readable and writable.  According to the datasheet:

    "LOWPOWER:When the bit is 1, close the internal benchmark
     clock of serial port to set into low-power status.

So it essentially gets mis-detected as Xscale, and gets
powered down in the process.  The device in question where
this was seen is listed by lspci as:

 Serial controller: Device 4348:3253 (rev 10) (prog-if 02 [16550])

Re-using the 353 quirk which just sets flags to fixed and type
to 16550 is suitable for fixing the 352 as well.

Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Wang YanQing 2013-03-05 23:16:48 +08:00 committed by Greg Kroah-Hartman
parent 503bded92d
commit 8b5c913f7e
1 changed files with 13 additions and 0 deletions
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13
drivers/tty/serial/8250/8250_pci.c
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@ -1554,6 +1554,7 @@ pci_wch_ch353_setup(struct serial_private *priv,
#define PCI_DEVICE_ID_PLX_CRONYX_OMEGA 0xc001
#define PCI_DEVICE_ID_INTEL_PATSBURG_KT 0x1d3d
#define PCI_VENDOR_ID_WCH 0x4348
#define PCI_DEVICE_ID_WCH_CH352_2S 0x3253
#define PCI_DEVICE_ID_WCH_CH353_4S 0x3453
#define PCI_DEVICE_ID_WCH_CH353_2S1PF 0x5046
#define PCI_DEVICE_ID_WCH_CH353_2S1P 0x7053
@ -2172,6 +2173,14 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = {
.subdevice = PCI_ANY_ID,
.setup = pci_wch_ch353_setup,
},
/* WCH CH352 2S card (16550 clone) */
{
.vendor = PCI_VENDOR_ID_WCH,
.device = PCI_DEVICE_ID_WCH_CH352_2S,
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID,
.setup = pci_wch_ch353_setup,
},
/*
* ASIX devices with FIFO bug
*/
@ -4870,6 +4879,10 @@ static struct pci_device_id serial_pci_tbl[] = {
PCI_ANY_ID, PCI_ANY_ID,
0, 0, pbn_b0_bt_2_115200 },
{ PCI_VENDOR_ID_WCH, PCI_DEVICE_ID_WCH_CH352_2S,
PCI_ANY_ID, PCI_ANY_ID,
0, 0, pbn_b0_bt_2_115200 },
/*
* Commtech, Inc. Fastcom adapters
*/