summaryrefslogtreecommitdiff
path: root/drivers/tty/serial/sh-sci.c
AgeCommit message (Collapse)AuthorFilesLines
2017-01-19serial: sh-sci: Remove manual break debouncingLaurent Pinchart1-117/+7
The sh-sci driver implements manual break debouncing for a few SH platforms by reading the value of the RX pin port register. This feature is optional and the driver considers all negative or zero values of the platform data port_reg field as invalid. As the four platforms that set the field to a register address all use an address higher than 0x7fffffff, the driver will always consider the value as invalid and never perform debouncing. The feature is unused, remove it. Debouncing could be implemented properly in the future using the pinctrl and GPIO APIs if desired. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19serial: sh-sci: Remove the platform data dma slave rx/tx channel IDsLaurent Pinchart1-17/+6
Only SH platforms still use platform data for the sh-sci, and none of them declare DMA channels connected to the SCI. Remove the corresponding platform data fields and simplify the driver accordingly. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19serial: sh-sci: Extend sci_port_params with more port parametersLaurent Pinchart1-81/+100
The fifo size, overrun register and mask, sampling rate mask and error mask all depend on the port type only and don't need to be computed at runtime. Add them to the sci_port_parameters structure. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19serial: sh-sci: Constify platform dataLaurent Pinchart1-48/+49
The driver modifies platform data for internal purpose only. Fix that and make the platform data structure const. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19serial: sh-sci: Replace regmap array with port parametersLaurent Pinchart1-123/+155
Turn the regmap two-dimensional array to an array of port parameters and store a pointer to the port parameters in the sci_port structure. This will allow handling additional port type dependent parameters. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19serial: sh-sci: Remove initialization of zero fields in sci_port_paramsLaurent Pinchart1-94/+0
The compiler zeros uninitialized fields, don't zero them manually. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19serial: sh-sci: Fix register offsets for the IRDA serial portLaurent Pinchart1-9/+8
Even though most of its registers are 8-bit wide, the IRDA has two 16-bit registers that make it a 16-bit peripheral and not a 8-bit peripheral with addresses shifted by one. Fix the registers offset in the driver and the platform data regshift value. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19serial: sh-sci: Don't rely on platform data flags when not neededLaurent Pinchart1-4/+3
The UPF_BOOT_AUTOCONF platform data flag is set by all platforms, hardcode it. The UPF_IOREMAP flag is set by a single SH platform and thus needs to be kept. However, for ARM platforms, we can base the decision on whether an OF node is present and bypass the platform data flags completely. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-19serial: sh-sci: Set the SCSCR TE and RE bits in the driverLaurent Pinchart1-6/+7
The Transmit Enable and Receive Enable bits are set in the scscr field of all instances of the sh-sci platform data. Set them in the driver directly to prepare for their removal from platform data. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-12tty: serial: sh-sci: set error code when kasprintf failsPan Bian1-1/+3
When the call to kasprintf() returns a NULL pointer, function sci_request_irq() frees the preallocated memory and returns 0 is returned. Because 0 means no error, the caller of sci_request_irq() will keep going, and the freed memory may be used or freed again. To avoid the above issue, this patch assigns "-ENOMEM" to the return variable ret. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188691 Signed-off-by: Pan Bian <bianpan2016@163.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-10serial: sh-sci: Fix deadlock caused by serial output requestTakatoshi Akiyama1-15/+5
While spin is already locked, serial output request causes the deadlock, because serial output process also tries to lock the spin. This patch removes serial output with spin locked. Signed-off-by: Takatoshi Akiyama <takatoshi.akiyama.kj@ps.hitachi-solutions.com> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com> Signed-off-by: Simon Horman <horms+renesas@verge.net.au> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-02tty: serial: constify uart_ops structuresJulia Lawall1-1/+1
Check for uart_ops structures that are only stored in the ops field of a uart_port structure. This field is declared const, so uart_ops structures that have this property can be declared as const also. The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @r disable optional_qualifier@ identifier i; position p; @@ static struct uart_ops i@p = { ... }; @ok@ identifier r.i; struct uart_port e; position p; @@ e.ops = &i@p; @bad@ position p != {r.p,ok.p}; identifier r.i; struct uart_ops e; @@ e@i@p @depends on !bad disable optional_qualifier@ identifier r.i; @@ static +const struct uart_ops i = { ... }; // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-26serial: sh-sci: Stop transfers in sci_shutdown()Geert Uytterhoeven1-0/+4
Make sure the transmitter and receiver are stopped when shutting down the port, and related interrupts are disabled. Without this: - New input data may be received into the RX FIFO, possibly triggering a new RX DMA completion, - Transfers will still be enabled on a subsequent startup of the UART, before the UART's FIFOs have been reset, causing reading of stale data. Inspired by a patch in the BSP by Koji Matsuoka <koji.matsuoka.xm@renesas.com>. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Clear (H)SCIF timeout and overrun during resetGeert Uytterhoeven1-0/+5
Add the missing timeout bit definition for (H)SCIF. Clear the timeout and overrun flag bits during UART reset, cfr. the initialization flowchart in the datasheet. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Clear RX, error, and break flags during resetGeert Uytterhoeven1-0/+4
Setting the FIFO reset bits is not sufficient to reset the RX FIFO. After this the status register's RDF flag bit may still be set, causing the reception of one stale byte of data. To fix this, clear all status flag bits related to reception, error, and break handling, cfr. the initialization flowchart in the datasheet. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Do not start transfers from sci_startup()Geert Uytterhoeven1-6/+0
FIFO reset is done in sci_reset(), called from sci_set_termios(), while sci_start_tx() and sci_start_rx() are called before, from sci_startup(). However, starting transfers before the UART's FIFOs have been reset may cause reading of stale data. Remove the calls to sci_start_tx() and sci_start_rx() from sci_startup() to fix this. Transfers are still started when needed: - sci_start_rx() is called from sci_set_termios() after FIFO reset, if the CREAD flag is set, - sci_start_tx() is called from uart_change_speed() immediately thereafter, if transmission is enabled. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Add DT support for dedicated RTS/CTSGeert Uytterhoeven1-0/+3
Add support for indicating the availability of dedicated lines for RTS/CTS hardware flow control, using the standard "uart-has-rtscts" DT property. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Fix support for hardware-assisted RTS/CTSGeert Uytterhoeven1-7/+83
The existing support for hardware-assisted RTS/CTS is rudimentary and doesn't work. Add support for hardware-assisted RTS/CTS hardware flow control for the (H)SCIF, SCIFA, and SCIFB variants. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Add pin initialization for SCIFA/SCIFBGeert Uytterhoeven1-1/+15
Before, the driver relied on initialization by the boot loader, or by implicit reset state. Note that unlike on (H)SCIF, the RTS/CTS bits exist only if dedicated RTS/CTS pins are available, which depends on the SoC and UART instance. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Correct pin initialization on (H)SCIFGeert Uytterhoeven1-15/+8
Correct pin initialization on (H)SCIF: - RTS must be deasserted (it's active low), - SCK must be an input, as it may be used as the optional external clock input. Initial pin configuration must always be done: - Regardless of the presence of dedicated RTS and CTS pins: if the register exists, the RTS/CTS bits exist, too, - Regardless of hardware flow control being enabled or not: RTS must be deasserted. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Do not open-code sci_getreg()Geert Uytterhoeven1-5/+2
Replace open-coded variants of sci_getreg() by function calls, and drop intermediate variables where appropriate. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Add support for GPIO-controlled modem linesGeert Uytterhoeven1-1/+45
Enhance the Renesas SCI UART driver to add support for GPIO-controlled modem lines (CTS, DSR, DCD, RNG, RTS, DTR), using the serial_mctrl_gpio helpers. GPIO-controlled modem lines can be used when dedicated modem lines are not available. Invalid configurations specifying both GPIO RTS/CTS and dedicated RTS/CTS are rejected. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25serial: sh-sci: Always set TIOCM_CTS in .get_mctrl() callbackGeert Uytterhoeven1-2/+2
Documentation/serial/driver clearly states: If the port does not support CTS, DCD or DSR, the driver should indicate that the signal is permanently active. Hence always set TIOCM_CTS, as we currently don't look at the CTS hardware line state at all. FWIW, this fixes the transmit path when hardware-assisted flow control is enabled, and userspace enables CRTSCTS. The receive path is still broken, as RTS is never asserted. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-08serial: sh-sci: Remove redundant instances of EARLYCON_DECLARE()Geert Uytterhoeven1-5/+0
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 <geert+renesas@glider.be> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07serial: sh-sci: Add support for SCIFA/SCIFB variable sampling ratesGeert Uytterhoeven1-2/+27
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 <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07serial: sh-sci: Use a bitmask to indicate supported sampling ratesGeert Uytterhoeven1-39/+27
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 <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07serial: sh-sci: Use premultiplier to handle half sampling rateGeert Uytterhoeven1-6/+10
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 <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07serial: sh-sci: Preserve SCIFA/SCIFB bit rate config for serial consoleGeert Uytterhoeven1-1/+2
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 <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07serial: sh-sci: Add more Serial Mode Register documentationGeert Uytterhoeven1-1/+1
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07serial: sh-sci: Add CONFIG_SERIAL_EARLYCON supportYoshinori Sato1-5/+72
"earlyprintk" is architecture specific option. General "earlycon" option support is much better. Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp> [uli: preserve other SCSCR bits when asserting RE and TE] Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com> [geert: rewording, #ifdef rework] Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-08serial: sh-sci: Remove cpufreq notifier to fix crash/deadlockGeert Uytterhoeven1-42/+0
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 <geert+renesas@glider.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-08Merge branch 'scif-clk-sck-brg-for-v4.5' of ↵Greg Kroah-Hartman1-152/+403
git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers into tty-next 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.
2015-12-17serial: sh-sci: Drop the sci_fck clock fallbackLaurent Pinchart1-5/+0
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 <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Add support for optional BRG on (H)SCIFGeert Uytterhoeven1-5/+80
Add support for using the Baud Rate Generator for External Clock (BRG), as found on some SCIF and HSCIF variants, to provide the sampling clock. This can improve baud rate range and accuracy. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Add support for optional external (H)SCK inputGeert Uytterhoeven1-3/+66
Add support for using the SCIx clock pin "(H)SCK" as an external clock input on (H)SCI(F), providing the sampling clock. Note that this feature is not yet supported on the select SCIFA variants that also have it (e.g. sh7723, sh7724, and r8a7740). On (H)SCIF variants with an External Baud Rate Generator (BRG), the BRG Clock Select Register must be configured for the external clock. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Prepare for multiple sampling clock sourcesGeert Uytterhoeven1-60/+134
Refactor the clock and baud rate parameter code to ease adding support for multiple sampling clock sources. sci_scbrr_calc() now returns the bit rate error, so it can be compared to the bit rate error using other sampling clock sources. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Correct SCIF type on R-Car for BRGGeert Uytterhoeven1-0/+11
The "renesas,scif" compatible value is currently used for the SCIF variant in all Renesas SoCs of the R-Car family. However, the variant used in the R-Car family is not the common "SH-4(A)" variant, but a derivative with added "Baud Rate Generator for External Clock" (BRG), which is also present in sh7734. Use the family-specific SCIF compatible values for R-Car Gen1, Gen2, and Gen3 SoCs to differentiate. The "renesas,scif" compatible value can still be used as a common denominator for SCIF variants with the "SH-4(A)" register layout (i.e. ignoring the "Serial Extension Mode Register" (SCEMR) and the new BRG-specific registers). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Correct SCIF type on RZ/A1HGeert Uytterhoeven1-0/+6
The "renesas,scif" compatible value is currently used for the SCIF variant in all Renesas SoCs of the R-Car and RZ families. However, the variant used in the RZ family is not the common "SH-4(A)" variant, but the "SH-2(A) with FIFO data count register" variant, as it has the "Serial Extension Mode Register" (SCEMR), just like on sh7203, sh7263, sh7264, and sh7269. Use the (already documented) SoC-specific "renesas,scif-r7s72100" compatible value to differentiate. The "renesas,scif" compatible value can still be used as a common denominator for SCIF variants with the "SH-4(A)" register layout (i.e. ignoring the SCEMR register). Note that currently both variants are treated the same, but this may change if support for the SCEMR register is ever added. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Replace struct sci_port_info by type/regtype encodingGeert Uytterhoeven1-29/+11
Store the encoded port and register types directly in of_device_id.data, instead of using a pointer to a structure. This saves memory and simplifies the source code, especially when adding more compatible entries later. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Add BRG register definitionsGeert Uytterhoeven1-0/+46
Add register definitions for the Baud Rate Generator for External Clock (BRG), as found in some SCIF and in HSCIF, including a new regtype for the "SH-4(A)"-derived SCIF variant with BRG. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Take into account sampling rate for max baud rateGeert Uytterhoeven1-1/+4
The maximum baud rate depends on the sampling rate. HSCIF has a variable sampling rate and sets s->sampling_rate to zero, hence use the minimum sampling rate of 8. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Merge sci_scbrr_calc() and sci_baud_calc_hscif()Geert Uytterhoeven1-23/+19
For low bit rates, the for-loop that reduces the divider returned by sci_scbrr_calc() and picks the clock select value may terminate without finding suitable values, leading to out-of-range divider and clock select values. sci_baud_calc_hscif() doesn't suffer from this problem, as it correctly uses clamp(). Since there are only two relevant differences between HSCIF and other variants w.r.t. bit rate configuration (fixed vs. variable sample rate, and an additional factor of two), sci_scbrr_calc() and sci_baud_calc_hscif() can be merged, fixing the issue with out-of-range values. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Avoid calculating the receive margin for HSCIFGeert Uytterhoeven1-27/+24
When assuming D = 0.5 and F = 0, maximizing the receive margin M is equivalent to maximizing the sample rate N. Hence there's no need to calculate the receive margin, as we can obtain the same result by iterating over all possible sample rates in reverse order, and skipping parameter sets that don't provide a lower bit rate error. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Improve bit rate error calculation for HSCIFGeert Uytterhoeven1-13/+8
The algorithm to find the best parameters for the requested bit rate calculates the relative bit rate error, using "(br * scrate) / 1000". For small "br * scrate", this has two problems: - The quotient may be zero, leading to a division by zero error, - This may introduce a large rounding error. Switch from relative to absolute bit rate error calculation to fix this. The default baud rate generator values can be removed, as there will always be one set of values that gives the smallest absolute error. Print the best set of values when debugging. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Avoid overflow in sci_baud_calc_hscif()Geert Uytterhoeven1-6/+19
If bps >= 1048576, the multiplication of the predivider and "bps" will overflow, and both br and err will contain bogus values. Skip the current and all higher clock select predividers when overflow is detected. Simplify the calculations using intermediates while we're at it. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Make unsigned values in sci_baud_calc_hscif() unsignedGeert Uytterhoeven1-5/+6
Move the -1 offset of br to the assignment to *brr, so br cannot become negative anymore, and update the clamp() call. Now all unsigned values in sci_baud_calc_hscif() can become unsigned. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Convert from clk_get() to devm_clk_get()Geert Uytterhoeven1-6/+4
Transfer clock cleanup handling to the core device management code. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Don't overwrite clock selection in serial_console_write()Geert Uytterhoeven1-3/+5
Blindly writing the default configuration value into the SCSCR register may change the clock selection bits, breaking the serial console if the current driver settings differ from the default settings. Keep the current clock selection bits to prevent this from happening on e.g. r8a7791/koelsch when support for the BRG will be added. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Drop unused frame_len parameter for sci_baud_calc_hscif()Geert Uytterhoeven1-21/+3
As F is assumed to be zero in the receive margin formula, frame_len is not used. Remove it, together with the sci_baud_calc_frame_len() helper function. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-17serial: sh-sci: Use existing local variable in sci_parse_dt()Geert Uytterhoeven1-1/+1
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
generated by cgit v1.2.3 (git 2.39.0) at 2025-09-29 01:08:41 +0300