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    SubjectRe: [PATCH 00/25] serial: sh-sci: Add external clock and BRG Support
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    Hi Geert,

    Thank you for the patches.

    For patches 3-6, 13, 15-16 and 22 and 24,

    Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

    I'm not sure I'd bother with patch 25/25, but I'm not against merging it
    either. I'd be surprised if the serial driver still worked at all on SH :-)

    On Thursday 19 November 2015 19:38:39 Geert Uytterhoeven wrote:
    > Hi,
    >
    > This patch series adds support to the Renesas SCI serial driver for
    > - the optional external clock on (H)SCI(F) and some SCIFA, where this
    > pin can serve as a clock input,
    > - the optional clock sources for the Baud Rate Generator for External
    > Clock (BRG), as found on some SCIF variants and on HSCIF.

    Could you briefly explain (and even better in a source code comment) how you
    handle baud rate calculation with the chained BRGs ?

    > Using external clocks increases the range and accuracy of supported baud
    > rates. Please see the descriptions of the DTS patches for more detailed
    > information regarding the impact on the supported platforms.
    >
    > For now this supports r8a7791/koelsch and r8a7795/salvator-x only, which
    > have an external SCIF_CLK running at 14.7456 MHz.
    > Support for other R-Car platforms will be added later.
    >
    > Testing:
    > - The Baud Rate Generator for External Clock (BRG) was tested with
    > SCIF and HSCIF on r8a7791/koelsch and r8a7795/salvator-x,
    > - The external clock input on (H)SCK was tested on r8a7795/salvator-x
    > by feeding an external clock signal to (H)SCIF1,
    > - Various bit rates were monitored using a SmartScope,
    > - Regression testing was done on Renesas ARM platforms that use SCIFA
    > as the console (r8a73a4/ape6evm, r8a7740/armadillo, and
    > sh73a0/kzm9g).
    >
    > Dependencies:
    > - This series depends on the series "[PATCH v2 00/16] serial: sh-sci:
    > Clock Cleanups",
    > - The SH patch 25 depends on the "serial: sh-sci" patches in this
    > series,
    > - The DTS patches 21-24 can be applied independently, once the DT
    > binding patches 1-2 are accepted,
    > - r8a7791/r8a7795 has a runtime dependency on series "[PATCH 0/2]
    > pinctrl: sh-pfc: r8a7791/r8a7795: Add SCIF_CLK support",
    > - r8a7795 also depends on
    > - platform support in e.g. renesas-drivers-2015-11-17-v4.4-rc1,
    > - "[PATCH] pinctrl: sh-pfc: r8a7795: Add HSCIF pins, groups, and
    > functions",
    > - "[PATCH] arm64: renesas: r8a7795 dtsi: Add all HSCIF nodes".
    > - Legacy SH has a runtime dependency on:
    > - series "[PATCH 0/2] drivers: sh: clk: Cleanup clock API",
    >
    > Thanks for your comments!
    >
    > Geert Uytterhoeven (25):
    > serial: sh-sci: Update DT binding documentation for external clock
    > input
    > serial: sh-sci: Update DT binding documentation for BRG support
    > serial: sh-sci: Drop useless check for zero sampling_rate
    > serial: sh-sci: Grammar s/Get ... for/Get ... from/
    > serial: sh-sci: Drop unused frame_len parameter for
    > sci_baud_calc_hscif()
    > serial: sh-sci: Don't overwrite clock selection in
    > serial_console_write()
    > serial: sh-sci: Convert from clk_get() to devm_clk_get()
    > serial: sh-sci: Make unsigned values in sci_baud_calc_hscif() unsigned
    > serial: sh-sci: Avoid overflow in sci_baud_calc_hscif()
    > serial: sh-sci: Improve bit rate error calculation for HSCIF
    > serial: sh-sci: Avoid calculating the receive margin for HSCIF
    > serial: sh-sci: Merge sci_scbrr_calc() and sci_baud_calc_hscif()
    > serial: sh-sci: Take into account sampling rate for max baud rate
    > serial: sh-sci: Add BRG register definitions
    > serial: sh-sci: Replace struct sci_port_info by type/regtype encoding
    > serial: sh-sci: Correct SCIF type on RZ/A1H
    > serial: sh-sci: Correct SCIF type on R-Car for BRG
    > serial: sh-sci: Prepare for multiple clocks and baud rate generators
    > serial: sh-sci: Add support for optional external (H)SCK input
    > serial: sh-sci: Add support for optional BRG on (H)SCIF
    > ARM: shmobile: r8a7791 dtsi: Add BRG support for (H)SCIF
    > ARM: shmobile: koelsch dts: Enable SCIF_CLK frequency and pins
    > arm64: renesas: r8a7795 dtsi: Add BRG support for (H)SCIF
    > arm64: renesas: salvator-x dts: Enable SCIF_CLK frequency and pins
    > sh: sh7734: Correct SCIF type for BRG
    >
    > .../bindings/serial/renesas,sci-serial.txt | 9 +
    > arch/arm/boot/dts/r8a7791-koelsch.dts | 13 +
    > arch/arm/boot/dts/r8a7791.dtsi | 54 ++-
    > arch/arm64/boot/dts/renesas/r8a7795-salvator-x.dts | 12 +
    > arch/arm64/boot/dts/renesas/r8a7795.dtsi | 74 ++-
    > arch/sh/kernel/cpu/sh4a/setup-sh7734.c | 12 +-
    > drivers/tty/serial/sh-sci.c | 530 ++++++++++++------
    > drivers/tty/serial/sh-sci.h | 5 +
    > include/linux/serial_sci.h | 1 +
    > 9 files changed, 508 insertions(+), 202 deletions(-)

    --
    Regards,

    Laurent Pinchart



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