diff options
Diffstat (limited to 'arch/blackfin/kernel/bfin_gpio.c')
| -rw-r--r-- | arch/blackfin/kernel/bfin_gpio.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/bfin_gpio.c b/arch/blackfin/kernel/bfin_gpio.c index 0182ce1fc4f..d9284d7dc9f 100644 --- a/arch/blackfin/kernel/bfin_gpio.c +++ b/arch/blackfin/kernel/bfin_gpio.c @@ -80,6 +80,7 @@ * GPIO_47 PH15 PF47 */ +#include <linux/delay.h> #include <linux/module.h> #include <linux/err.h> #include <asm/blackfin.h> @@ -888,3 +889,20 @@ void gpio_direction_output(unsigned short gpio) local_irq_restore(flags); } EXPORT_SYMBOL(gpio_direction_output); + +/* If we are booting from SPI and our board lacks a strong enough pull up, + * the core can reset and execute the bootrom faster than the resistor can + * pull the signal logically high. To work around this (common) error in + * board design, we explicitly set the pin back to GPIO mode, force /CS + * high, and wait for the electrons to do their thing. + * + * This function only makes sense to be called from reset code, but it + * lives here as we need to force all the GPIO states w/out going through + * BUG() checks and such. + */ +void bfin_gpio_reset_spi0_ssel1(void) +{ + port_setup(P_SPI0_SSEL1, GPIO_USAGE); + gpio_bankb[gpio_bank(P_SPI0_SSEL1)]->data_set = gpio_bit(P_SPI0_SSEL1); + udelay(1); +} |