Refine SPI bitbanging
Change the SPI bitbanging core to fix a subtle bug (which had no
effect so far) and to make integration of the RayeR SPIPGM and Nvidia
MCP6x/MCP7x SPI patches easier. Kill a few global variables and require
explicit initialization of bitbanging delay.
A big to Johannes Sjölund for testing an earlier version of the code as
part of the Nvidia MCP6x/MCP7x SPI bitbanging patch.
Corresponding to flashrom svn r1085.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Michael Karcher <flashrom@mkarcher.dialup.fu-berlin.de>
diff --git a/bitbang_spi.c b/bitbang_spi.c
index 6316a55..b543fd4 100644
--- a/bitbang_spi.c
+++ b/bitbang_spi.c
@@ -26,46 +26,55 @@
#include "chipdrivers.h"
#include "spi.h"
-/* Length of half a clock period in usecs */
-int bitbang_spi_half_period = 0;
+/* Length of half a clock period in usecs. */
+static int bitbang_spi_half_period;
-enum bitbang_spi_master bitbang_spi_master = BITBANG_SPI_INVALID;
+static enum bitbang_spi_master bitbang_spi_master = BITBANG_SPI_INVALID;
-const struct bitbang_spi_master_entry bitbang_spi_master_table[] = {
+static const struct bitbang_spi_master_entry bitbang_spi_master_table[] = {
{}, /* This entry corresponds to BITBANG_SPI_INVALID. */
};
const int bitbang_spi_master_count = ARRAY_SIZE(bitbang_spi_master_table);
-void bitbang_spi_set_cs(int val)
+/* Note that CS# is active low, so val=0 means the chip is active. */
+static void bitbang_spi_set_cs(int val)
{
bitbang_spi_master_table[bitbang_spi_master].set_cs(val);
}
-void bitbang_spi_set_sck(int val)
+static void bitbang_spi_set_sck(int val)
{
bitbang_spi_master_table[bitbang_spi_master].set_sck(val);
}
-void bitbang_spi_set_mosi(int val)
+static void bitbang_spi_set_mosi(int val)
{
bitbang_spi_master_table[bitbang_spi_master].set_mosi(val);
}
-int bitbang_spi_get_miso(void)
+static int bitbang_spi_get_miso(void)
{
return bitbang_spi_master_table[bitbang_spi_master].get_miso();
}
-int bitbang_spi_init(void)
+int bitbang_spi_init(enum bitbang_spi_master master, int halfperiod)
{
+ bitbang_spi_master = master;
+ bitbang_spi_half_period = halfperiod;
+
+ if (bitbang_spi_master == BITBANG_SPI_INVALID) {
+ msg_perr("Invalid bitbang SPI master. \n"
+ "Please report a bug at flashrom@flashrom.org\n");
+ return 1;
+ }
bitbang_spi_set_cs(1);
bitbang_spi_set_sck(0);
- buses_supported = CHIP_BUSTYPE_SPI;
+ bitbang_spi_set_mosi(0);
return 0;
}
-uint8_t bitbang_spi_readwrite_byte(uint8_t val)
+static uint8_t bitbang_spi_readwrite_byte(uint8_t val)
{
uint8_t ret = 0;
int i;