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path: root/drivers/auxdisplay/charlcd.c
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2021-07-16auxdisplay: charlcd: Drop unneeded initializers and switch to C99 styleAndy Shevchenko1-3/+1
For structure initializers the fields are 0 (or NULL) by default, so there is no need to fill them explicitly. Besides that, much easier to read when initializers use C99 style. Hence, convert to C99 style as well. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-03-16auxdisplay: Remove in_interrupt() usage.Sebastian Andrzej Siewior1-10/+8
charlcd_write() is invoked as a VFS->write() callback and as such it is always invoked from preemptible context and may sleep. charlcd_puts() is invoked from register/unregister callback which is preemptible. The reboot notifier callback is also invoked from preemptible context. Therefore there is no need to use in_interrupt() to figure out if it is safe to sleep because it always is. in_interrupt() and related context checks are being removed from non-core code. Using schedule() to schedule (and be friendly to others) is discouraged and cond_resched() should be used instead. Remove in_interrupt() and use cond_resched() to schedule every 32 iterations if needed. Link: https://lkml.kernel.org/r/20200914204209.256266093@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> [mo: fixed a couple typos in comment and commit message] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: charlcd: Do not print chars at end of lineLars Poeschel1-0/+3
Skip printing characters at the end of a display line. This fits to the behaviour we already had, that the cursor is nailed to the last position of a line. This might slightly change behaviour. On hd44780 displays with one or two lines the previous implementation did still write characters to the buffer of the display even if they are currently not visible. The shift_display command could be used to set the "viewing window" to a new position in the buffer and then you could see the characters previously written. This described behaviour does not work for hd44780 displays with more than two display lines. There simply is not enough buffer. So the behaviour was a bit inconsistent across different displays. The new behaviour is to stop writing characters at the end of a visible line, even if there would be room in the buffer. This allows us to have an easy implementation, that should behave equal on all supported displays. This is not hd44780 hardware dependent anymore. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Change gotoxy calling interfaceLars Poeschel1-5/+5
Change the calling interface for gotoxy from supplying the x and y coordinates in the charlcd struct to explicitly supplying x and y in the function arguments. This is more intuitive and allows for moving the cursor to positions independent from the position saved in the charlcd struct. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: charlcd: replace last device specific stuffLars Poeschel1-8/+3
These are the last bits left in charlcd.c that are device specific and they are removed now. In detail this is: * bwidth, which is the width of the display buffer per line. This is replaced by width of the display. * hwidth, which is the size of the display buffer as a whole. This is replaced by looping all chars of a line by all lines. * the hd44780_common header include can go away. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: hd44780: Remove clear_fastLars Poeschel1-15/+6
We remove the hd44780_clear_fast (display) clear implementation. With the new timeout the normal clear_display is reasonably fast. So there is no need for a clear_fast anymore. Link: https://lore.kernel.org/lkml/20200922092121.GG16421@1wt.eu/ Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Call charlcd_backlight in placeLars Poeschel1-8/+6
This moves the call to charlcd_backlight from the end of the switch into the actual case statement that originates the change of the backlight. This is more consistent to what is now found in this switch. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Move char redefine code to hd44780_commonLars Poeschel1-55/+5
Take the code to redefine characters out of charlcd and move it to hd44780_common, as this is hd44780 specific. There is now a function hd44780_common_redefine_char that drivers use and charlcd calls it through its ops function pointer. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: cleanup unnecessary hd44780 code in charlcdLars Poeschel1-31/+1
This cleans up now unnecessary hd44780 specific code from charlcd. We obsoleted this with the last patch. So another chunk of hd44780 specific code can be dropped from charlcd. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: implement various hd44780_common_ functionsLars Poeschel1-27/+46
This implements various hd44780_common_ functions for hd44780 compatible display drivers to use. charlcd then calls these functions through its ops function pointer. The functions namely are: - hd44780_common_shift_cursor - hd44780_common_display_shift - hd44780_common_display - hd44780_common_cursor - hd44780_common_blink - hd44780_common_fontsize - hd44780_common_lines Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Move init_display to hd44780_commonLars Poeschel1-89/+6
The init_display function is moved over to hd44780_common. charlcd uses it via its ops function pointer and drivers initialize the ops with the common hd44780_common_init_display function. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Make use of enum for backlight on / offLars Poeschel1-3/+3
To turn the backlight on or off use our new enum CHARLCD_ON / CHARLCD_OFF. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: make charlcd_backlight visible to hd44780_commonLars Poeschel1-1/+2
hd44780_common wants to use the charlcd_backlight function, so make it visible. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Move clear_display to hd44780_commonLars Poeschel1-16/+6
This moves the clear_display function from charlcd to hd44780_common. This is one more step to make charlcd independent from device specific code. The two hd44780 drivers use the new function from hd44780_common and charlcd calls this function through its function pointer in its ops structure. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: add home to charlcd_opsLars Poeschel1-1/+1
This adds a home function to the charlcd_ops struct and offer an implementation for hd44780_common. This implementation is used by our two hd44780 drivers. This is to make charlcd device independent. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: provide hd44780_common_gotoxyLars Poeschel1-27/+11
Provide a hd44780_common_gotoxy function and a pointer in the ops for charlcd to use to move the cursor. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: hd44780_common_printLars Poeschel1-13/+15
We create a hd44780_common_print function. It is derived from the original charlcd_print. charlcd_print becomes a device independent print function, that then only calls via its ops function pointers, into the print function offered by drivers. Reported-by: kernel test robot <lkp@intel.com> Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Move addr out of charlcd_privLars Poeschel1-36/+25
Move out the struct addr from struct charlcd_priv into the less private struct charlcd. This member is used to pass position information. The individual drivers need to be able to read this information, so we move this out of charlcd_priv to charlcd structure. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Move write_cmd pointers to hd44780 driversLars Poeschel1-22/+23
The write_cmd function is used to send commands to hd44780 displays. The individual hd44780 drivers then implement their appropriate way of doing this with their supported displays. So we move this pointer so hd44780_common. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Move write_data pointer to hd44780_commonLars Poeschel1-6/+6
This moves the write_data function pointer from struct charlcd_ops to struct hd44780_common. This is the function that actually writes the character to the display. This hd44780 hardware specific function is used by two drivers at the moment. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Move ifwidth to struct hd44780_commonLars Poeschel1-6/+6
Move struct charlcd member ifwidth to our new struct hd44780_common. ifwidth is hd44780 device specific and is used by two drivers at the moment, so we move it to a common place, where both can use this. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Move hwidth and bwidth to struct hd44780_commonLars Poeschel1-20/+20
hwidth is for the hardware buffer size and bwidth is for the buffer width of one single line. This is specific to the hd44780 displays and so it is moved out from charlcd to struct hd44780_common. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-11-04auxdisplay: Use an enum for charlcd backlight on/off opsLars Poeschel1-1/+1
We use an enum for calling the functions in charlcd, that turn the backlight on or off. This enum is generic and can be used for other charlcd turn on / turn off operations as well. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2020-05-30auxdisplay: charlcd: Reuse hex_to_bin() instead of custom codeAndy Shevchenko1-11/+6
hex_to_bin() may be used to convert hexdecimal digit to its binary representation. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2020-03-23Merge 5.6-rc7 into char-misc-nextGreg Kroah-Hartman1-1/+1
We need the char/misc driver fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-18misc: cleanup minor number definitions in c file into miscdevice.hZhenzhong Duan1-2/+0
HWRNG_MINOR and RNG_MISCDEV_MINOR are duplicate definitions, use unified HWRNG_MINOR instead and moved into miscdevice.h ANSLCD_MINOR and LCD_MINOR are duplicate definitions, use unified LCD_MINOR instead and moved into miscdevice.h MISCDEV_MINOR is renamed to PXA3XX_GCU_MINOR and moved into miscdevice.h Other definitions are just moved without any change. Link: https://lore.kernel.org/lkml/20200120221323.GJ15860@mit.edu/t/ Suggested-by: Arnd Bergmann <arnd@arndb.de> Build-tested-by: Willy TARREAU <wtarreau@haproxy.com> Build-tested-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com> Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Link: https://lore.kernel.org/r/20200311071654.335-2-zhenzhong.duan@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07auxdisplay: charlcd: replace zero-length array with flexible-array memberGustavo A. R. Silva1-1/+1
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2019-12-05auxdisplay: charlcd: deduplicate simple_strtoul()Andy Shevchenko1-27/+7
Like in commit 8b2303de399f ("serial: core: Fix handling of options after MMIO address") we may use simple_strtoul() which in comparison to kstrtoul() can do conversion in-place without additional and unnecessary code to be written. Link: http://lkml.kernel.org/r/20190801192904.41087-2-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Mans Rullgard <mans@mansr.com> Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-08auxdisplay: charlcd: move charlcd.h to drivers/auxdisplayMasahiro Yamada1-1/+1
This header is included in drivers/auxdisplay/. Make it a local header. Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2019-03-17auxdisplay: charlcd: make backlight initial state configurableMans Rullgard1-1/+9
The charlcd driver currently flashes the backlight once on init. This may not be desirable. Thus, add options for turning the backlight off or on as well. Signed-off-by: Mans Rullgard <mans@mansr.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2019-03-17auxdisplay: charlcd: simplify init message displayMans Rullgard1-7/+8
If CONFIG_PANEL_CHANGE_MESSAGE is set, CONFIG_PANEL_BOOT_MESSAGE will also be defined, so the double ifdef is pointless. Simplify the code further by using an intermediate macro rather duplicating most of the line. Signed-off-by: Mans Rullgard <mans@mansr.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2019-03-17auxdisplay: charlcd: Introduce charlcd_free() helperAndy Shevchenko1-0/+6
The charlcd_free() is a counterpart to charlcd_alloc() and should be called symmetrically on tear down. Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2019-03-17auxdisplay: charlcd: Move to_priv() to charlcd namespaceAndy Shevchenko1-13/+13
In order to be more particular in names, rename to_priv() macro to charlcd_to_priv(). No functional change intended. Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-12-21auxdisplay: charlcd: fix x/y command parsingMans Rullgard1-0/+3
The x/y command parsing has been broken since commit 129957069e6a ("staging: panel: Fixed checkpatch warning about simple_strtoul()"). Commit b34050fadb86 ("auxdisplay: charlcd: Fix and clean up handling of x/y commands") fixed some problems by rewriting the parsing code, but also broke things further by removing the check for a complete command before attempting to parse it. As a result, parsing is terminated at the first x or y character. This reinstates the check for a final semicolon. Whereas the original code use strchr(), this is wasteful seeing as the semicolon is always at the end of the buffer. Thus check this character directly instead. Signed-off-by: Mans Rullgard <mans@mansr.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-08-01auxdisplay: charlcd: delete mdelay in long_sleepJia-Ju Bai1-4/+1
The function long_sleep() calls mdelay() when in an interrupt handler. But only charlcd_clear_display() and charlcd_init_display calls long_sleep(), and my tool finds that the two functions are never called in an interrupt handler. Thus mdelay() and in_interrupt() are not necessary. This is found by a static analysis tool named DCNS written by myself. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Acked-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-04-12auxdisplay: Replace licenses with SPDX identifiersMiguel Ojeda1-5/+1
Cc: Philippe Ombredanne <pombredanne@nexb.com> Acked-by: Willy Tarreau <w@1wt.eu> Acked-by: Linus Walleij <triad@dflund.se> Acked-by: Robin van der Gracht <robin@protonic.nl> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-04-12auxdisplay: charlcd: Fix and clean up handling of x/y commandsMiguel Ojeda1-17/+78
The current version is not parsing multiple x/y commands as the code originally intended. On top of that, kstrtoul() expects NULL-terminated strings. Finally, the code does two passes over the string. Some explanations about the supported syntax are added as well. Cc: Willy Tarreau <w@1wt.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Robert Abel <rabel@robertabel.eu> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-04-12auxdisplay: charlcd: fix hex literal ranges for graphics commandRobert Abel1-2/+2
The graphics command expects 16 hexadecimal literals, but would allow characters in range [0-9a-zA-Z] instead of [0-9a-fA-F]. Signed-off-by: Robert Abel <rabel@robertabel.eu> Acked-by: Willy Tarreau <w@1wt.eu> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-04-12auxdisplay: charlcd: fix two-line command ^[[LN not marked as processedRobert Abel1-0/+1
Signed-off-by: Robert Abel <rabel@robertabel.eu> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-04-12auxdisplay: charlcd: replace octal literal with form-feed escape sequenceRobert Abel1-1/+1
There is no need to resort to octal escape sequence for the form feed character when an established escape sequence exists. Signed-off-by: Robert Abel <rabel@robertabel.eu> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-04-12auxdisplay: charlcd: use null character instead of zero literal to terminate ↵Robert Abel1-2/+2
strings Using '\0' instead of plain 0 makes the intent clearer that this is indeed a string and not a series of integers. Signed-off-by: Robert Abel <rabel@robertabel.eu> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-04-12auxdisplay: charlcd: no need to call charlcd_gotoxy() if nothing changesSean Young1-3/+4
If the line extends beyond the width to the screen, nothing changes. The existing code will call charlcd_gotoxy every time for this case. Signed-off-by: Sean Young <sean@mess.org> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2017-09-18auxdisplay: charlcd: properly restore atomic counter on error pathWilly Tarreau1-2/+9
Commit f4757af ("staging: panel: Fix single-open policy race condition") introduced in 3.19-rc1 attempted to fix a race condition on the open, but failed to properly do it and used to exit without restoring the semaphore. This results in -EBUSY being returned after the first open error until the module is reloaded or the system restarted (ie: consecutive to a dual open resulting in -EBUSY or to a permission error). [ Note for stable maintainers: the code moved from drivers/misc/panel.c to drivers/auxdisplay/{charlcd,panel}.c during 4.12. The patch easily applies there (modulo the renamed atomic counter) but I can provide a tested backport if desired. ] Fixes: f4757af85 # 3.19-rc1 Cc: stable@vger.kernel.org Cc: Mariusz Gorski <marius.gorski@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-17auxdisplay: charlcd: Add support for displays with more than two linesGeert Uytterhoeven1-9/+13
On displays with more than two lines, the additional lines are stored in the buffers used for the first two lines, but beyond the visible parts. Adjust the DDRAM address calculation to cater for this. When clearing the display, avoid writing more spaces than the actual size of the physical buffer. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-17auxdisplay: charlcd: Add support for 4-bit interfacesGeert Uytterhoeven1-6/+30
In 4-bit mode, 8-bit commands and data are written using two raw writes to the data interface: high nibble first, low nibble last. This must be handled by the low-level driver. However, as we don't know in which mode (4-bit or 8-bit) nor 4-bit phase the LCD was left, initialization must always be handled using raw writes, and needs to configure the LCD for 8-bit mode first. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-17auxdisplay: charlcd: Extract character LCD core from misc/panelGeert Uytterhoeven1-0/+790
Extract the character LCD core from the Parallel port LCD/Keypad Panel driver in the misc subsystem, and convert it into a subdriver in the auxdisplay subsystem. This allows the character LCD core to be used by other drivers later. Compilation is controlled by its own Kconfig symbol CHARLCD, which is to be selected by its users, but can be enabled manually for compile-testing. All functions changed their prefix from "lcd_" to "charlcd_", and gained a "struct charlcd *" parameter to operate on a specific instance. While the driver API thus is ready to support multiple instances, the current limitation of a single display (/dev/lcd has a single misc minor assigned) is retained. No functional changes intended. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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