As platform_get_irq() now prints an error when the interrupt does not
exist, scary warnings may be printed for optional interrupts:

    sh-sci e6550000.serial: IRQ index 1 not found
    sh-sci e6550000.serial: IRQ index 2 not found
    sh-sci e6550000.serial: IRQ index 3 not found
    sh-sci e6550000.serial: IRQ index 4 not found
    sh-sci e6550000.serial: IRQ index 5 not found

Fix this by calling platform_get_irq_optional() instead for all but the
first interrupts, which are optional.

Fixes: 7723f4c5 ("driver core: platform: Add an error message to platform_get_irq*()")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Reviewed-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20191001180743.1041-1-geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The sifive serial driver implements earlycon support, but unless
another driver is built in that supports earlycon support it won't
be usable.  Explicitly select SERIAL_EARLYCON instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NPaul Walmsley <paul.walmsley@sifive.com>
Link: https://lore.kernel.org/r/20190910055923.28384-1-hch@lst.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

'exit' functions should be marked as __exit, not __init.

Fixes: c10b1332 ("tty: serial: Add RDA8810PL UART driver")
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20190910041702.7357-1-christophe.jaillet@wanadoo.frSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

'exit' functions should be marked as __exit, not __init.

Fixes: fc60a8b6 ("tty: serial: owl: Implement console driver")
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20190910041129.6978-1-christophe.jaillet@wanadoo.frSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add PIO mode support in receive and transmit path with RX interrupt
trigger of 16 bytes for Tegra194 and older chips.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-13-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Standard UART controllers support +/-4% baud rate error tolerance.
Tegra186 only supports 0% to +4% error tolerance whereas other Tegra
chips support standard +/-4% rate. Add chip data for knowing error
tolerance level for each soc. Creating new compatible for Tegra194
chip as it supports baud rate error tolerance of -2 to +2%, different
from older chips.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-12-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support to adjust baud rates to fall under supported tolerance
range through DT.

Tegra186 chip has a hardware issue resulting in frame errors when
tolerance level for baud rate is negative. Provided entries to adjust
baud rate to be within acceptable range and work with devices that
can send negative baud rate. Also report error when baud rate set is
out of tolerance range of controller updated in device tree.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-11-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support to use 8 bytes trigger for Tegra186 SOC.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-9-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Set maximum number of UART ports to 8 as older chips have 5 ports and
Tergra186 and later chips will have 8 ports. Add this info to chip
data. Read device tree compatible of this driver and register uart
driver with max ports of matching chip data.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-8-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Chips prior to Tegra186 needed delay of 3 UART clock cycles to avoid
data loss. This issue is fixed in Tegra186 and a new flag is added to
check if FIFO mode is enabled. chip data updated to check if this flag
is available for a chip. Tegra186 has new compatible to enable this
flag.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-7-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Report overrun/parity/frame/break errors to top tty layer. Add support
to ignore break character if IGNBRK is set.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-5-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

FIFO reset/flush code implemented now does not follow programming
guidelines. RTS line has to be turned off while flushing FIFOs to
avoid new transfers. Also check LSR bits UART_LSR_TEMT and UART_LSR_DR
to confirm FIFOs are flushed.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-4-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This avoids two race conditions from the UART shutdown sequence both
leading to 'Machine check error in AXI2APB' and kernel oops.

One was that the clock was disabled before the DMA was terminated making
it possible for the DMA callbacks to be called after the clock was
disabled. These callbacks could write to the UART registers causing
timeout.

The second was that the clock was disabled before the UART was
completely flagged as closed. This is done after the shutdown is called
and a new write could be started after the clock was disabled.
tegra_uart_start_pio_tx could be called causing timeout.

Given that the baud rate is reset at the end of shutdown sequence, this
fix is to examine the baud rate to avoid register access from both race
conditions.

Besides, terminate the DMA before disabling the clock.
Signed-off-by: NAhung Cheng <ahcheng@nvidia.com>
Signed-off-by: NShardar Mohammed <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-3-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support to ignore read characters if CREAD flag is not set.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-2-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The sequence of arguments which was passed to handle_lsr_errors() didn't
match the parameters defined in that function, &lsr was passed to flag
and &flag was passed to lsr, this patch fixed that.

Fixes: b7396a38 ("tty/serial: Add Spreadtrum sc9836-uart driver support")
Signed-off-by: NChunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: NChunyan Zhang <zhang.lyra@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190905074151.5268-1-zhang.lyra@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As documented in the data-sheet, the transmitter must be disabled before
activating AutoCTS or auto transmitter flow control. Accordingly, the
transmitter must be enabled after AutoCTS or auto transmitter flow
control gets deactivated.
Signed-off-by: NChristoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
Link: https://lore.kernel.org/r/20190904121746.4641-1-c.vogtlaender@sigma-surface-science.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 391f93f2 ("serial: core: Rework hw-assisted flow control
support") has changed the way the AutoCTS mode is handled.

According to that change, serial drivers which enable H/W AutoCTS mode must
set UPSTAT_AUTORTS, UPSTAT_AUTOCTS and UPSTAT_AUTOXOFF to prevent the
serial core from inadvertently disabling RX or TX. This patch adds proper
handling of UPSTAT_AUTORTS, UPSTAT_AUTOCTS and UPSTAT_AUTOXOFF flags.
Signed-off-by: NChristoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
Link: https://lore.kernel.org/r/20190904121141.4570-1-c.vogtlaender@sigma-surface-science.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/fsl_linflexuart.c:907:3-8: No need to set .owner here. The core will do it.

 Remove .owner field if calls are used which set it automatically

Generated by: scripts/coccinelle/api/platform_no_drv_owner.cocci

Fixes: b953815b819b ("tty: serial: Add linflexuart driver for S32V234")
CC: Stefan-gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Signed-off-by: Nkbuild test robot <lkp@intel.com>
Reviewed-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20190825142837.zt3hpa22c7iofg3v@48261080c7f1Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The "fsl,s32-linflexuart" compatible string is too generic. Make it SoC
specific.
Signed-off-by: NStefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Link: https://lore.kernel.org/r/20190823191115.18490-4-stefan-gabriel.mirea@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When tearing down the n_gsm ldisc while one or more of its child ports
are open, a lock dep warning occurs:

[   56.254258] ======================================================
[   56.260447] WARNING: possible circular locking dependency detected
[   56.266641] 5.2.0-00118-g1fd58e20e5b0 #30 Not tainted
[   56.271701] ------------------------------------------------------
[   56.277890] cmux/271 is trying to acquire lock:
[   56.282436] 8215283a (&tty->legacy_mutex){+.+.}, at: __tty_hangup.part.0+0x58/0x27c
[   56.290128]
[   56.290128] but task is already holding lock:
[   56.295970] e9e2b842 (&gsm->mutex){+.+.}, at: gsm_cleanup_mux+0x9c/0x15c
[   56.302699]
[   56.302699] which lock already depends on the new lock.
[   56.302699]
[   56.310884]
[   56.310884] the existing dependency chain (in reverse order) is:
[   56.318372]
[   56.318372] -> #2 (&gsm->mutex){+.+.}:
[   56.323624]        mutex_lock_nested+0x1c/0x24
[   56.328079]        gsm_cleanup_mux+0x9c/0x15c
[   56.332448]        gsmld_ioctl+0x418/0x4e8
[   56.336554]        tty_ioctl+0x96c/0xcb0
[   56.340492]        do_vfs_ioctl+0x41c/0xa5c
[   56.344685]        ksys_ioctl+0x34/0x60
[   56.348535]        ret_fast_syscall+0x0/0x28
[   56.352815]        0xbe97cc04
[   56.355791]
[   56.355791] -> #1 (&tty->ldisc_sem){++++}:
[   56.361388]        tty_ldisc_lock+0x50/0x74
[   56.365581]        tty_init_dev+0x88/0x1c4
[   56.369687]        tty_open+0x1c8/0x430
[   56.373536]        chrdev_open+0xa8/0x19c
[   56.377560]        do_dentry_open+0x118/0x3c4
[   56.381928]        path_openat+0x2fc/0x1190
[   56.386123]        do_filp_open+0x68/0xd4
[   56.390146]        do_sys_open+0x164/0x220
[   56.394257]        kernel_init_freeable+0x328/0x3e4
[   56.399146]        kernel_init+0x8/0x110
[   56.403078]        ret_from_fork+0x14/0x20
[   56.407183]        0x0
[   56.409548]
[   56.409548] -> #0 (&tty->legacy_mutex){+.+.}:
[   56.415402]        __mutex_lock+0x64/0x90c
[   56.419508]        mutex_lock_nested+0x1c/0x24
[   56.423961]        __tty_hangup.part.0+0x58/0x27c
[   56.428676]        gsm_cleanup_mux+0xe8/0x15c
[   56.433043]        gsmld_close+0x48/0x90
[   56.436979]        tty_ldisc_kill+0x2c/0x6c
[   56.441173]        tty_ldisc_release+0x88/0x194
[   56.445715]        tty_release_struct+0x14/0x44
[   56.450254]        tty_release+0x36c/0x43c
[   56.454365]        __fput+0x94/0x1e8

Avoid the warning by doing the port hangup asynchronously.
Signed-off-by: NMartin Hundebøll <martin@geanix.com>
Link: https://lore.kernel.org/r/20190822215601.9028-1-martin@geanix.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The sprd serial console can work with only 26M fixed clock,
but the probe() is returning fail if the clock "enable" is not
configured in device tree.

This patch will fix the problem to let the uart device which is
used for console can be initialized even missing "enable" clock
configured in devicetree. We should make sure the debug function
as available as we can.
Signed-off-by: NChunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: NChunyan Zhang <zhang.lyra@gmail.com>
Reviewed-by: NBaolin Wang <baolin.wang@linaro.org>
Tested-by: NBaolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/20190826072929.7696-4-zhang.lyra@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use console_initcall to save the console index we selected on the
command line to sprd_console before probe finished. Thus we can
make different processes to the uart devices during initialization
according to whether it is used for console.
Signed-off-by: NChunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: NChunyan Zhang <zhang.lyra@gmail.com>
Reviewed-by: NBaolin Wang <baolin.wang@linaro.org>
Tested-by: NBaolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/20190826072929.7696-3-zhang.lyra@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When calling sprd_console_setup(), sprd_uart_port probably is NULL,
we should check that first instead of checking its items directly.

Also we should check membase to avoid accessing uart device before
its initialization finished.
Signed-off-by: NChunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: NChunyan Zhang <zhang.lyra@gmail.com>
Reviewed-by: NBaolin Wang <baolin.wang@linaro.org>
Tested-by: NBaolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/20190826072929.7696-2-zhang.lyra@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 18dfef9c ("serial: atmel: convert to irq handling
provided mctrl-gpio"), the GPIOs interrupts are handled by
mctrl_gpio_irq_handle().
So, atmel_get_lines_status() can be completely killed and replaced by :
atmel_uart_readl(port, ATMEL_US_CSR);
Suggested-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NRichard Genoud <richard.genoud@gmail.com>
Link: https://lore.kernel.org/r/20190826071752.30396-1-richard.genoud@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This should help to avoid unnecessary gaps in transmission while
adding little overhead due to low default Tx threshold level (2
bytes).
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-6-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

imx_set_termios(): avoid writing baud rate divider registers when the
values to be written are the same as current. Any writing seems to
restart transmission/receiving logic in the hardware, that leads to
data breakage even when rate doesn't in fact change. E.g., user
switches RTS/CTS handshake and suddenly gets broken bytes.
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-5-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

imx_set_termios(): disabling individual interrupt requests in UART for
duration of the routine is pointless. Get rid of it.
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-4-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

imx_set_termios(): stopping receiver and transmitter does harm when
something that doesn't touch transmission format/rate changes, such as
RTS/CTS handshake.

OTOH, it does no good on baud rate or format change, as
synchronization on upper-level protocols is still required to do it
right.

Therefore, just stop doing it.
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-3-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

imx_set_termios(): remove busy-waiting "drain Tx FIFO" loop. Worse
yet, it was potentially unbounded wait due to RTS/CTS (hardware)
handshake.

Let user space ensure draining is done before termios change, if
draining is needed in the first place.
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-2-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A recent change split the insertion loop into two parts. The first part
accessed bytes 0, 1, ... (rxlen - 2), and the second part by mistake
took offset `rxlen` instead of the correct `rxlen - 1`. So one byte was
not stored, and the final access wrote past the end of the rx_buf.

Fixes: 9c12d739 (tty: max310x: Split uart characters insertion loop)
Signed-off-by: NJan Kundrát <jan.kundrat@cesnet.cz>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/13ea227620aaad8a7231d42ed03a8508297d4eb3.1567027079.git.jan.kundrat@cesnet.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

spinlock can be initialized automatically with DEFINE_SPINLOCK()
rather than explicitly calling spin_lock_init().
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20190827114614.102037-1-weiyongjun1@huawei.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There may be setups, where legacy interrupts are not available. This is
the caese, e.g., when Linux runs as guest (aka. non-root cell) of the
partitioning hypervisor Jailhouse. There, only MSI(-X) interrupts are
available for guests.

But the 8250_pci driver currently only supports legacy ints. So let's
enable MSI(-X) interrupts.

Nevertheless, this needs to handled with care: while many 8250 devices
actually claim to support MSI(-X) interrupts it should not be enabled be
default. I had at least one device in my hands with broken MSI
implementation.

So better introduce a whitelist with devices that are known to support
MSI(-X) interrupts. I tested all devices mentioned in the patch.
Signed-off-by: NRalf Ramsauer <ralf.ramsauer@oth-regensburg.de>
Link: https://lore.kernel.org/r/20190812112152.693622-1-ralf.ramsauer@oth-regensburg.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fintek F81504A/508A/512A is PCIE to 4/8/12 UARTs device. It's support
IO/MMIO/PCIE conf to access all functions. The old F81504/508/512 is
only support IO.
Signed-off-by: NJi-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
Link: https://lore.kernel.org/r/1565933249-23076-1-git-send-email-hpeter+linux_kernel@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Description of the modem line control GPIOs contain a boolean type to set
direction of the line. Since GPIO library provides an enumerator type of flags,
we may utilize it and allow a bit more flexibility on the choice of the type of
the line parameters. It also removes an additional layer of value conversion.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NStefan Roese <sr@denx.de>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20190814140759.17486-1-andriy.shevchenko@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When CONFIG_SERIAL_FSL_LINFLEXUART=y and CONFIG_PRINTK is not set,
one compilation error is found as below:
drivers/tty/serial/fsl_linflexuart.c: In function linflex_earlycon_putchar:
drivers/tty/serial/fsl_linflexuart.c:608:31: error: CONFIG_LOG_BUF_SHIFT undeclared
(first use in this function); did you mean CONFIG_ISA_BUS_API?
  if (earlycon_buf.len >= 1 << CONFIG_LOG_BUF_SHIFT)
                               ^~~~~~~~~~~~~~~~~~~~
                               CONFIG_ISA_BUS_API
This because CONFIG_LOG_BUF_SHIFT is depended on CONFIG_PRINTK, fix this
by adding dependence for CONFIG_SERIAL_FSL_LINFLEXUART.

Fixes: b953815b819b ("tty: serial: Add linflexuart driver for S32V234")
Signed-off-by: NMao Wenan <maowenan@huawei.com>
Link: https://lore.kernel.org/r/20190820124015.28409-1-maowenan@huawei.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Guessing the first tty for a gsm0710 multiplexed serial device is not
currently possible, which makes it racy to use with multiple modems.

Add a way to map the physical serial tty to its related mux devices
using an ioctl.
Signed-off-by: NMartin Hundebøll <martin@geanix.com>
Link: https://lore.kernel.org/r/20190812211243.98686-1-martin@geanix.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Moxa serial boards only need a special setup function, we can use
generic 8250 framework for other parts.

So let's merge 8250_moxa to 8250_pci.
Signed-off-by: NKai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20190816165124.16942-1-kai.heng.feng@canonical.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add loopback function support for Spreadtrum serial controller.
Signed-off-by: NBaolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/1275cd9968f1ceb5ac049cc23f1e508025cd552f.1566375260.git.baolin.wang@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 1d267ea6 ("serial: mctrl-gpio: simplify init
routine"), mctrl_gpio_init() returns failure if the assignment to any
member of the gpio array results in an error pointer.
Since commit c359522194593815 ("serial: mctrl_gpio: Avoid probe failures
in case of missing gpiolib"), mctrl_gpio_to_gpiod() returns NULL in the
!CONFIG_GPIOLIB case.
Hence there is no longer a need to check for mctrl_gpio_to_gpiod()
returning an error value.  A simple NULL check is sufficient.

This follows the spirit of commit 445df7ff ("serial: mctrl-gpio:
drop usages of IS_ERR_OR_NULL") in the mctrl-gpio core.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20190814092924.13857-3-geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 1d267ea6 ("serial: mctrl-gpio: simplify init
routine"), mctrl_gpio_init() returns failure if the assignment to any
member of the gpio array results in an error pointer.
Since commit c359522194593815 ("serial: mctrl_gpio: Avoid probe failures
in case of missing gpiolib"), mctrl_gpio_to_gpiod() returns NULL in the
!CONFIG_GPIOLIB case.
Hence there is no longer a need to check for mctrl_gpio_to_gpiod()
returning an error value.  A simple NULL check is sufficient.

This follows the spirit of commit 445df7ff ("serial: mctrl-gpio:
drop usages of IS_ERR_OR_NULL") in the mctrl-gpio core.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20190814092924.13857-4-geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>