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![Jim Cromie](/assets/img/avatar_default.png)
GPIO SUPPORT FOR SCx200 & PC8736x The patch-set reworks the 2.4 vintage scx200_gpio driver for modern 2.6, and refactors GPIO support to reuse it in a new driver for the GPIO on PC-8736x chips. Its handy for the Soekris.com net-4801, which has both chips. These patches have been seen recently on Kernel-Mentors, and then Kernel-Newbies ML, where Jesper Juhl kindly reviewed it. His feedback has been incorporated. Thanks Jesper ! Its also gone to soekris-tech@soekris.com for possible testing by linux folks, I've gotten 1 promise so far. Theyre mostly BSD folk over there, but we'll see.. Device-file & Sysfs The driver preserves the existing device-file interface, including the write/cmd set, but adds v to 'view' the pin-settings & configs by inducing, via gpio_dump(), a dev_info() call. Its a fairly crappy way to get status, but it sticks to the syslog approach, conservatively. Allowing users to voluntarily trigger logging is good, it gives them a familiar way to confirm their app's control & use of the pins, and I've thus reduced the pin-mode-updates from dev_info to dev_dbg. I've recently bolted on a proto sysfs interface for both new drivers. Im not including those patches here; they (the patch + doc-pre-patch) are still quite raw (and unreviewed on KNML), and since they 'invent' a convention for GPIO, a proper vetting is needed. Since this patchset is much bigger than my previous ones, Id like to keep things simpler, and address it 1st, before bolting on more stuff. The driver-split The Geode CPU and the PC-87366 Super-IO chip have GPIO units which share a common pin-architecture (same pin features, with same bits controlling), but with different addressing mechanics and port organizations. The vintage driver expresses the pin capabilities with pin-mode commands [OoPpTt],etc that change the pin configurations, and since the 2 chips share pin-arch, we can reuse the read(), write() commands, once the implementation is suitably adjusted. The patchset adds a vtable: struct nsc_gpio_ops, to abstract the existing gpio operations, then adjusts fileops.write() code to invoke operations via that vtable. Driver specific open()s set private_data to the vtable so its available for use by write(). The vtable gets the gpio_dump() too, since its user-friendly, and (could be construed as) part of the current device-file interface. To support use of dev_dbg() in write() & _dump(), the vtable gets a dev ptr too, set by both scx200 & pc8736x _gpio drivers. heres how the pins are presented in syslog: [ 1890.176223] scx200_gpio.0: io00: 0x0044 TS OD PUE EDGE LO DEBOUNCE [ 1890.287223] scx200_gpio.0: io01: 0x0003 OE PP PUD EDGE LO nsc_gpio.c: new file is new home of several file-ops methods, which are modified to get their vtable from filp->private_data, and use it where needed. scx200_gpio.c: keeps some of its existing gpio routines, but now wires them up via the vtable (they're invoked by nsc_gpio.c:nsc_gpio_write() thru this vtable). A driver-spcific open() initializes filp->private_data with the vtable. Once the split is clean, and the scx200_gpio driver is working, we copy and modify the function and variable names, and rework the access-method bodies for the different addressing scheme. Heres a working overview of the patchset: # series file for GPIO # Spring Cleaning gpio-scx/patch.preclean # scripts/Lindent fixes, editor-ctrl comments # API Modernization gpio-scx/patch.api26 # what I learned from LDD3 gpio-scx/patch.platform-dev-2 # get pdev, support for dev_dbg() gpio-scx/patch.unsigned-minor # fix to match std practice # Debuggability gpio-scx/patch.dump-diet # shrink gpio_dump() gpio-scx/patch.viewpins # add new 'command' to call dump() gpio-scx/patch.init-refactor # pull shadow-register init to sub # Access-Abstraction (add vtable) gpio-scx/patch.access-vtable # introduce nsg_gpio_ops vtable, w dump gpio-scx/patch.vtable-calls # add & use the vtable in scx200_gpio gpio-scx/patch.nscgpio-shell # add empty driver for common-fops # move code under abstraction gpio-scx/patch.migrate-fops # move file-ops methods from scx200_gpio gpio-scx/patch.common-dump # mv scx200.c:scx200_gpio_dump() to nsc_gpio.c gpio-scx/patch.add-pc8736x-gpio # add new driver, like old, w chip adapt # gpio-scx/patch.add-DEBUG # enable all dev_dbg()s # Cleanups # finish printk -> dev_dbg() etc gpio-scx/patch.pdev-pc8736x # new drvr needs pdev too, gpio-scx/patch.devdbg-nscgpio # add device to 'vtable', use in dev_dbg() # gpio-scx/patch.pin-config-view # another 'c' 'command' # gpio-scx/quiet-getset # take out excess dbg stuff (pretty quiet now) gpio-scx/patch.shadow-current # imitate scx200_gpio's shadow regs in pc87* # post KMentors-post patches .. gpio-scx/patch.mutexes # use mutexes for config-locks gpio-scx/patch.viewpins-values # extend dump to obsolete separate 'c' cmd gpio-scx/patch.kconfig # add stuff for kbuild # TBC # combine api26 with pdev, which is just one step. # merge c&v commands to single do-all-fn # delay viewpins, dump-diet should also un-ifdef it too. diff.sys-gpio-rollup-1 This patch: Removed editor format-control comments, and used scripts/Lindent to clean up whitespace, then deleted the bogus chunks :-( Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
51 lines
1.8 KiB
C
51 lines
1.8 KiB
C
/* linux/include/linux/scx200.h
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Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
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Defines for the National Semiconductor SCx200 Processors
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*/
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/* Interesting stuff for the National Semiconductor SCx200 CPU */
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extern unsigned scx200_cb_base;
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#define scx200_cb_present() (scx200_cb_base!=0)
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/* F0 PCI Header/Bridge Configuration Registers */
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#define SCx200_DOCCS_BASE 0x78 /* DOCCS Base Address Register */
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#define SCx200_DOCCS_CTRL 0x7c /* DOCCS Control Register */
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/* GPIO Register Block */
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#define SCx200_GPIO_SIZE 0x2c /* Size of GPIO register block */
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/* General Configuration Block */
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#define SCx200_CB_BASE_FIXED 0x9000 /* Base fixed at 0x9000 according to errata? */
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/* Watchdog Timer */
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#define SCx200_WDT_OFFSET 0x00 /* offset within configuration block */
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#define SCx200_WDT_SIZE 0x05 /* size */
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#define SCx200_WDT_WDTO 0x00 /* Time-Out Register */
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#define SCx200_WDT_WDCNFG 0x02 /* Configuration Register */
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#define SCx200_WDT_WDSTS 0x04 /* Status Register */
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#define SCx200_WDT_WDSTS_WDOVF (1<<0) /* Overflow bit */
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/* High Resolution Timer */
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#define SCx200_TIMER_OFFSET 0x08
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#define SCx200_TIMER_SIZE 0x05
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/* Clock Generators */
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#define SCx200_CLOCKGEN_OFFSET 0x10
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#define SCx200_CLOCKGEN_SIZE 0x10
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/* Pin Multiplexing and Miscellaneous Configuration Registers */
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#define SCx200_MISC_OFFSET 0x30
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#define SCx200_MISC_SIZE 0x10
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#define SCx200_PMR 0x30 /* Pin Multiplexing Register */
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#define SCx200_MCR 0x34 /* Miscellaneous Configuration Register */
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#define SCx200_INTSEL 0x38 /* Interrupt Selection Register */
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#define SCx200_IID 0x3c /* IA On a Chip Identification Number Reg */
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#define SCx200_REV 0x3d /* Revision Register */
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#define SCx200_CBA 0x3e /* Configuration Base Address Register */
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#define SCx200_CBA_SCRATCH 0x64 /* Configuration Base Address Scratchpad */
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