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To use these, set things up like this:
#define UART_PA_START 0x67000000 Physical address of UART
struct uart_ctlr *uart = (struct uart_ctlr *)UART_PA_START;
#define UART_FBCON_RANGE 5:3 Bit range for the FBCON field
enum { An enum with allowed values
UART_FBCON_OFF,
UART_FBCON_ON,
UART_FBCON_MULTI,
UART_FBCON_SLAVE,
};
This defines a bit field of 3 bits starting at bit 5 and extending down
to bit 3, i.e. 5:3
Then:
bitfield_unpack(UART_FBCON)
- return the value of bits 5:3 (shifted down to bits 2:0)
bitfield_pack(UART_FBCON, 4)
- return a word with that field set to 4 (so in this case (4 << 3))
bitfield_set(UART_FBCON, word, val
- update a field within word so that its value is val.
bitfield_enum_writel(UART_FBCON, MULTI, &uart->fbcon)
- set the UART's FBCON field to MULTI
Change-Id: Id90aa0538093d67c917df2d744c0ebff1fe03b6f
BUG=chromium-os:13875
TEST=cd test; make
Review URL: http://codereview.chromium.org/6883058
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