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| author | Gregory Nutt <gnutt@nuttx.org> | 2014-12-21 14:09:04 -0600 |
|---|---|---|
| committer | Gregory Nutt <gnutt@nuttx.org> | 2014-12-21 14:09:04 -0600 |
| commit | 55ff857fdd75da4f086fbff603758d905211eb90 (patch) | |
| tree | 189d5a549c896c1fdc2c3083f6146fb5d945df42 /nuttx/arch/arm/src/tiva/tiva_gpio.c | |
| parent | 778cf11f47e79d94829b7cd430c4184f966b7b73 (diff) | |
| download | nuttx-55ff857fdd75da4f086fbff603758d905211eb90.tar.gz nuttx-55ff857fdd75da4f086fbff603758d905211eb90.tar.bz2 nuttx-55ff857fdd75da4f086fbff603758d905211eb90.zip | |
Improved comments
Diffstat (limited to 'nuttx/arch/arm/src/tiva/tiva_gpio.c')
| -rw-r--r-- | nuttx/arch/arm/src/tiva/tiva_gpio.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/nuttx/arch/arm/src/tiva/tiva_gpio.c b/nuttx/arch/arm/src/tiva/tiva_gpio.c index e2fae8f2a..99c1a7058 100644 --- a/nuttx/arch/arm/src/tiva/tiva_gpio.c +++ b/nuttx/arch/arm/src/tiva/tiva_gpio.c @@ -835,9 +835,17 @@ int tiva_configgpio(uint32_t cfgset) flags = irqsave(); - /* Enable power and clocking for this GPIO peripheral. */ + /* Enable power and clocking for this GPIO peripheral. + * + * - Enable Power (TM4C129 family only): Applies power (only) to the GPIO + * peripheral. This is not an essential step since enabling clocking + * will also apply power. The only significance is that the GPIO state + * will be retained if the GPIO clocking is subsequently disabled. + * - Enable Clocking (All families): Applies both power and clocking to + * the GPIO peripheral, bringing it a fully functional state. + */ - tiva_gpio_enablepwr(port); /* State will be retained of clocking disabled */ + tiva_gpio_enablepwr(port); tiva_gpio_enableclk(port); /* First, set the port to digital input. This is the safest state in which |