read_zsreg(9) [centos man page]

READ_ZSREG(9)							Internal Functions						     READ_ZSREG(9)

NAME

       read_zsreg - Read a register from a Z85230

SYNOPSIS

       u8 read_zsreg(struct z8530_channel * c, u8 reg);

ARGUMENTS

       c
	   Z8530 channel to read from (2 per chip)

       reg
	   Register to read

FIXME

       Use a spinlock.

       Most of the Z8530 registers are indexed off the control registers. A read is done by writing to the control register and reading the
       register back. The caller must hold the lock

AUTHOR

       Alan Cox <alan@lxorguk.ukuu.org.uk>
	   Author.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014							     READ_ZSREG(9)

STRUCT 
IRQ_CHIP_GENE(9) 					    Structures						   STRUCT IRQ_CHIP_GENE(9)

NAME

       struct_irq_chip_generic - Generic irq chip data structure

SYNOPSIS

       struct irq_chip_generic {
	 raw_spinlock_t lock;
	 void __iomem * reg_base;
	 unsigned int irq_base;
	 unsigned int irq_cnt;
	 u32 mask_cache;
	 u32 type_cache;
	 u32 polarity_cache;
	 u32 wake_enabled;
	 u32 wake_active;
	 unsigned int num_ct;
	 void * private;
	 struct list_head list;
	 struct irq_chip_type chip_types[0];
       };

MEMBERS

       lock
	   Lock to protect register and cache data access

       reg_base
	   Register base address (virtual)

       irq_base
	   Interrupt base nr for this chip

       irq_cnt
	   Number of interrupts handled by this chip

       mask_cache
	   Cached mask register

       type_cache
	   Cached type register

       polarity_cache
	   Cached polarity register

       wake_enabled
	   Interrupt can wakeup from suspend

       wake_active
	   Interrupt is marked as an wakeup from suspend source

       num_ct
	   Number of available irq_chip_type instances (usually 1)

       private
	   Private data for non generic chip callbacks

       list
	   List head for keeping track of instances

       chip_types[0]
	   Array of interrupt irq_chip_types

DESCRIPTION

       Note, that irq_chip_generic can have multiple irq_chip_type implementations which can be associated to a particular irq line of an
       irq_chip_generic instance. That allows to share and protect state in an irq_chip_generic instance when we need to implement different flow
       mechanisms (level/edge) for it.

AUTHORS

       Thomas Gleixner <tglx@linutronix.de>
	   Author.

       Ingo Molnar <mingo@elte.hu>
	   Author.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   STRUCT IRQ_CHIP_GENE(9)