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Tive System Control: Add logic to configure the alternatie clock source (ALTCLK). Needed by the Tiva timer module

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This commit is contained in:
Gregory Nutt 2015-01-09 14:10:31 -06:00
parent 7384857658
commit 9ae597c441
3 changed files with 32 additions and 6 deletions
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22
arch/arm/src/tiva/tiva_timer.c
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@ -47,7 +47,9 @@
#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <arch/irq.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "chip/tiva_syscontrol.h"
@ -86,6 +88,7 @@ struct tiva_gptmstate_s
/* Variable state values */
uint32_t frequency; /* Frequency of the input clock */
uint32_t imr; /* Interrupt mask value. Zero if no interrupts */
#ifdef CONFIG_TIVA_TIMER_REGDEBUG
@ -1436,7 +1439,7 @@ TIMER_HANDLE tiva_gptm_configure(const struct tiva_gptmconfig_s *config)
while (!tiva_emac_periphrdy());
up_udelay(250);
/* Select the alternal timer clock source is so reuested. The general
/* Select the alternate timer clock source is so requested. The general
* purpose timer has the capability of being clocked by either the system
* clock or an alternate clock source. By setting the ALTCLK bit in the
* GPTM Clock Configuration (GPTMCC) register, software can selects an
@ -1446,10 +1449,11 @@ TIMER_HANDLE tiva_gptm_configure(const struct tiva_gptmconfig_s *config)
*
* NOTE: The actual alternate clock source selection is a global property
* and cannot be configure on a timer-by-timer basis here. That selection
* must be done by common logic early in the initialization sequence.
* must be done by common logic earlier in the initialization sequence.
*
* In any case, the caller must provide us with the correct source
* frequency in gptm->frequency field.
* NOTE: Both the frequency of the SysClk (SYSCLK_FREQUENCY) and of the
* alternate clock (ALTCLK_FREQUENCY) must be provided in the board.h
* header file.
*/
if (config->alternate)
@ -1459,6 +1463,16 @@ TIMER_HANDLE tiva_gptm_configure(const struct tiva_gptmconfig_s *config)
regval = tiva_getreg(priv, TIVA_TIMER_CC_OFFSET);
regval |= TIMER_CC_ALTCLK;
tiva_putreg(priv, TIVA_TIMER_CC_OFFSET, regval);
/* Remember the frequency of the input clock */
priv->frequency = ALTCLK_FREQUENCY;
}
else
{
/* Remember the frequency of the input clock */
priv->frequency = SYSCLK_FREQUENCY;
}
/* Then [re-]configure the timer into the new configuration */

3
arch/arm/src/tiva/tiva_timer.h
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@ -212,8 +212,7 @@ struct tiva_gptmconfig_s
{
uint8_t gptm; /* GPTM number */
uint8_t mode; /* See enum tiva_timer32mode_e */
uint8_t alternate; /* False: Use SysClk; True: Use alternate clock source */
uint32_t frequency; /* Frequency of the selected clock source */
bool alternate; /* False: Use SysClk; True: Use alternate clock source */
};
/* This structure is cast compatible with struct tiva_gptmconfig_s and

13
arch/arm/src/tiva/tm4c129_syscontrol.c
View File

@ -397,4 +397,17 @@ void up_clockconfig(void)
pllfreq0 = M2PLLFREQ0(BOARD_PLL_MINT, BOARD_PLL_MFRAC);
pllfreq1 = QN2PLLFREQ1(BOARD_PLL_Q, BOARD_PLL_N);
tiva_clockconfig(pllfreq0, pllfreq1, BOARD_PLL_SYSDIV);
/* Set up the alternate clock source
*
* The ALTCLK provides a clock source of numerous frequencies to the
* general-purpose timer, SSI, and UART modules. The default source for
* the ALTCLK is the Precision Internal Oscillator (PIOSC). The
* Hibernation Real-time Clock (RTCOSC) and Low Frequency Internal
* Oscillator (LFIOSC) are alternatives. If the RTCOSC Output is
* selected, the clock source must also be enabled in the Hibernation
* module.
*/
putreg32(BOARD_ALTCLKCFG, TIVA_SYSCON_ALTCLKCFG);
}