linux/drivers/tty/serial/sh-sci.c, branch v4.7

serial: sh-sci: Remove redundant instances of EARLYCON_DECLARE()

2016-03-08T00:11:14Z

As of commit 2eaa790989e03900 ("earlycon: Use common framework for earlycon declarations") it is no longer needer to specify both EARLYCON_DECLARE() and OF_EARLYCON_DECLARE(). Signed-off-by: Geert Uytterhoeven Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Add support for SCIFA/SCIFB variable sampling rates

2016-02-07T06:54:55Z

Add support for sparse variable sampling rates on SCIFA and SCIFB. According to the datasheet, sampling rate 1/5 needs a small quirk to avoid corrupting the first byte received. This increases the range and accuracy of supported baud rates. E.g. on r8a7791/koelsch: - Supports now 134, 150, and standard 500000-4000000 bps, - Perfect match for 134, 150, 500000, 1000000, 2000000, and 4000000 bps, - Accuracy has increased for most standard bps values. Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Use a bitmask to indicate supported sampling rates

2016-02-07T06:54:55Z

Replace the single sampling rate and special handling for HSCIF's variable sampling rates by a bitmask and a custom iterator. This prepares for the advent of SCIFA/SCIFB's sparse variable sampling rates. Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Use premultiplier to handle half sampling rate

2016-02-07T06:54:55Z

On SCIx variants different from HSCIF, the bit rate is equal to the sampling clock rate divided by half the sampling rate. Currently this is handled by dividing the sampling rate by two, which was OK as it was always even. Replace halving the sampling rate by premultiplying the base clock frequency by 2, to accommodate odd sampling rates on SCIFA/SCIFB later. Replace the shift value in the BRG divider calculation by a premultiplication of the base clock frequency too, for consistency. Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Preserve SCIFA/SCIFB bit rate config for serial console

2016-02-07T06:54:55Z

SCIFA and SCIFB have additional bit rate config bits in the Serial Mode Register. Don't touch them when using the port as a serial console, as we rely on the boot loader to have configured the serial port config. Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Add more Serial Mode Register documentation

2016-02-07T06:54:55Z

Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support

2016-02-07T06:51:04Z

"earlyprintk" is architecture specific option. General "earlycon" option support is much better. Signed-off-by: Yoshinori Sato [uli: preserve other SCSCR bits when asserting RE and TE] Signed-off-by: Ulrich Hecht [geert: rewording, #ifdef rework] Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Remove cpufreq notifier to fix crash/deadlock

2016-01-08T05:08:05Z

The BSP team noticed that there is spin/mutex lock issue on sh-sci when CPUFREQ is used. The issue is that the notifier function may call mutex_lock() while the spinlock is held, which can lead to a BUG(). This may happen if CPUFREQ is changed while another CPU calls clk_get_rate(). Taking the spinlock was added to the notifier function in commit e552de2413edad1a ("sh-sci: add platform device private data"), to protect the list of serial ports against modification during traversal. At that time the Common Clock Framework didn't exist yet, and clk_get_rate() just returned clk->rate without taking a mutex. Note that since commit d535a2305facf9b4 ("serial: sh-sci: Require a device per port mapping."), there's no longer a list of serial ports to traverse, and taking the spinlock became superfluous. To fix the issue, just remove the cpufreq notifier: 1. The notifier doesn't work correctly: all it does is update stored clock rates; it does not update the divider in the hardware. The divider will only be updated when calling sci_set_termios(). I believe this was broken back in 2004, when the old drivers/char/sh-sci.c driver (where the notifier did update the divider) was replaced by drivers/serial/sh-sci.c (where the notifier just updated port->uartclk). Cfr. full-history-linux commits 6f8deaef2e9675d9 ("[PATCH] sh: port sh-sci driver to the new API") and 3f73fe878dc9210a ("[PATCH] Remove old sh-sci driver"). 2. On modern SoCs, the sh-sci parent clock rate is no longer related to the CPU clock rate anyway, so using a cpufreq notifier is futile. Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman

Merge branch 'scif-clk-sck-brg-for-v4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers into tty-next

2016-01-08T05:04:46Z

Geert writes: Summary: - Clean up the naming of clocks in the sh-sci driver and its DT bindings, - Add support for the optional external clock on (H)SCI(F), where this pin can serve as a clock input, - Add support for the optional clock sources for the Baud Rate Generator for External Clock (BRG), as found on some SCIF variants and on HSCIF.

serial: sh-sci: Drop the sci_fck clock fallback

2015-12-17T10:19:12Z

All platforms that used to define an sci_fck clock have now switched to the fck name. Remove the fallback code. Signed-off-by: Laurent Pinchart Acked-by: Simon Horman Signed-off-by: Geert Uytterhoeven Acked-by: Greg Kroah-Hartman