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

Geert Uytterhoeven
2015-11-19T18:45:39Z

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.
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(-)

--
1.9.1

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds