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drivers/bcm2835: Add support for SWDIO direction control pin 

Adds a new, optional configuration "bcm2835gpio_swdio_dir_num" to
the BCM2835 driver, to control the direction of an external buffer
driver IC in SWD mode. For example, this is needed to use a level-
shifting buffer, such as the SN74LVC2T45 used on the JTAG Hat

Change-Id: If5c146f310ecf8ceae85443b3670936467d2786d
Signed-off-by: Matthew Mets <matt@blinkinlabs.com>
Reviewed-on: http://openocd.zylin.com/6371
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins
This commit is contained in:
Matthew Mets 2021-07-20 01:28:05 +02:00 committed by Antonio Borneo
parent c8f92ee73b
commit 44d7cc31da
1 changed files with 41 additions and 4 deletions
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45
src/jtag/drivers/bcm2835gpio.c
View File

@ -86,6 +86,8 @@ static int swclk_gpio = -1;
static int swclk_gpio_mode;
static int swdio_gpio = -1;
static int swdio_gpio_mode;
static int swdio_dir_gpio = -1;
static int swdio_dir_gpio_mode;
/* Transition delay coefficients */
static int speed_coeff = 113714;
@ -149,10 +151,20 @@ static int bcm2835gpio_reset(int trst, int srst)
static void bcm2835_swdio_drive(bool is_output)
{
if (is_output)
OUT_GPIO(swdio_gpio);
else
INP_GPIO(swdio_gpio);
if (swdio_dir_gpio > 0) {
if (is_output) {
GPIO_SET = 1 << swdio_dir_gpio;
OUT_GPIO(swdio_gpio);
} else {
INP_GPIO(swdio_gpio);
GPIO_CLR = 1 << swdio_dir_gpio;
}
} else {
if (is_output)
OUT_GPIO(swdio_gpio);
else
INP_GPIO(swdio_gpio);
}
}
static int bcm2835_swdio_read(void)
@ -295,6 +307,15 @@ COMMAND_HANDLER(bcm2835gpio_handle_swd_gpionum_swdio)
return ERROR_OK;
}
COMMAND_HANDLER(bcm2835gpio_handle_swd_dir_gpionum_swdio)
{
if (CMD_ARGC == 1)
COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swdio_dir_gpio);
command_print(CMD, "BCM2835 num: swdio_dir = %d", swdio_dir_gpio);
return ERROR_OK;
}
COMMAND_HANDLER(bcm2835gpio_handle_speed_coeffs)
{
if (CMD_ARGC == 2) {
@ -374,6 +395,13 @@ static const struct command_registration bcm2835gpio_command_handlers[] = {
.help = "gpio number for swdio.",
.usage = "[swdio]",
},
{
.name = "bcm2835gpio_swdio_dir_num",
.handler = &bcm2835gpio_handle_swd_dir_gpionum_swdio,
.mode = COMMAND_CONFIG,
.help = "gpio number for swdio direction control pin (set=output mode, clear=input mode)",
.usage = "[swdio_dir]",
},
{
.name = "bcm2835gpio_srst_num",
.handler = &bcm2835gpio_handle_jtag_gpionum_srst,
@ -541,6 +569,12 @@ static int bcm2835gpio_init(void)
OUT_GPIO(srst_gpio);
}
if (swdio_dir_gpio != -1) {
swdio_dir_gpio_mode = MODE_GPIO(swdio_dir_gpio);
GPIO_SET = 1 << swdio_dir_gpio;
OUT_GPIO(swdio_dir_gpio);
}
LOG_DEBUG("saved pinmux settings: tck %d tms %d tdi %d "
"tdo %d trst %d srst %d", tck_gpio_mode, tms_gpio_mode,
tdi_gpio_mode, tdo_gpio_mode, trst_gpio_mode, srst_gpio_mode);
@ -567,5 +601,8 @@ static int bcm2835gpio_quit(void)
if (srst_gpio != -1)
SET_MODE_GPIO(srst_gpio, srst_gpio_mode);
if (swdio_dir_gpio != -1)
SET_MODE_GPIO(swdio_dir_gpio, swdio_dir_gpio_mode);
return ERROR_OK;
}