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avr32: Add gclk helper functions

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Add two helper functions for configuring and enabling generic clocks:
  - gclk_enable_output: Enables output on a GCLKx pin
  - gclk_set_rate: Configures a gclk to run at a specific rate

This should eliminate any reason to go mucking about with PM registers
from board code.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
This commit is contained in:
Haavard Skinnemoen 2008-08-31 18:05:32 +02:00
parent ab0df36fc7
commit 98090cd75c
2 changed files with 122 additions and 2 deletions
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25
cpu/at32ap/at32ap700x/clk.c
View file

@ -25,6 +25,7 @@
#include <asm/arch/clk.h>
#include <asm/arch/memory-map.h>
#include <asm/arch/portmux.h>
#include "sm.h"
@ -66,3 +67,27 @@ void clk_init(void)
sm_writel(PM_MCCTRL, SM_BIT(PLLSEL));
#endif
}
unsigned long __gclk_set_rate(unsigned int id, enum gclk_parent parent,
unsigned long rate, unsigned long parent_rate)
{
unsigned long divider;
if (rate == 0 || parent_rate == 0) {
sm_writel(PM_GCCTRL(id), 0);
return 0;
}
divider = (parent_rate + rate / 2) / rate;
if (divider <= 1) {
sm_writel(PM_GCCTRL(id), parent | SM_BIT(CEN));
rate = parent_rate;
} else {
divider = min(255, divider / 2 - 1);
sm_writel(PM_GCCTRL(id), parent | SM_BIT(CEN) | SM_BIT(DIVEN)
| SM_BF(DIV, divider));
rate = parent_rate / (2 * (divider + 1));
}
return rate;
}

99
include/asm-avr32/arch-at32ap700x/clk.h
View file

@ -23,11 +23,13 @@
#define __ASM_AVR32_ARCH_CLK_H__
#include <asm/arch/chip-features.h>
#include <asm/arch/portmux.h>
#ifdef CONFIG_PLL
#define MAIN_CLK_RATE ((CFG_OSC0_HZ / CFG_PLL0_DIV) * CFG_PLL0_MUL)
#define PLL0_RATE ((CFG_OSC0_HZ / CFG_PLL0_DIV) * CFG_PLL0_MUL)
#define MAIN_CLK_RATE PLL0_RATE
#else
#define MAIN_CLK_RATE (CFG_OSC0_HZ)
#define MAIN_CLK_RATE (CFG_OSC0_HZ)
#endif
static inline unsigned long get_cpu_clk_rate(void)
@ -87,4 +89,97 @@ extern void gclk_init(void) __attribute__((weak));
/* Board code may need the SDRAM base clock as a compile-time constant */
#define SDRAMC_BUS_HZ (MAIN_CLK_RATE >> CFG_CLKDIV_HSB)
/* Generic clock control */
enum gclk_parent {
GCLK_PARENT_OSC0 = 0,
GCLK_PARENT_OSC1 = 1,
GCLK_PARENT_PLL0 = 2,
GCLK_PARENT_PLL1 = 3,
};
/* Some generic clocks have specific roles */
#define GCLK_DAC_SAMPLE_CLK 6
#define GCLK_LCDC_PIXCLK 7
extern unsigned long __gclk_set_rate(unsigned int id, enum gclk_parent parent,
unsigned long rate, unsigned long parent_rate);
/**
* gclk_set_rate - configure and enable a generic clock
* @id: Which GCLK[id] to enable
* @parent: Parent clock feeding the GCLK
* @rate: Target rate of the GCLK in Hz
*
* Returns the actual GCLK rate in Hz, after rounding to the nearest
* supported rate.
*
* All three parameters are usually constant, hence the inline.
*/
static inline unsigned long gclk_set_rate(unsigned int id,
enum gclk_parent parent, unsigned long rate)
{
unsigned long parent_rate;
if (id > 7)
return 0;
switch (parent) {
case GCLK_PARENT_OSC0:
parent_rate = CFG_OSC0_HZ;
break;
#ifdef CFG_OSC1_HZ
case GCLK_PARENT_OSC1:
parent_rate = CFG_OSC1_HZ;
break;
#endif
#ifdef PLL0_RATE
case GCLK_PARENT_PLL0:
parent_rate = PLL0_RATE;
break;
#endif
#ifdef PLL1_RATE
case GCLK_PARENT_PLL1:
parent_rate = PLL1_RATE;
break;
#endif
default:
parent_rate = 0;
break;
}
return __gclk_set_rate(id, parent, rate, parent_rate);
}
/**
* gclk_enable_output - enable output on a GCLK pin
* @id: Which GCLK[id] pin to enable
* @drive_strength: Drive strength of external GCLK pin, if applicable
*/
static inline void gclk_enable_output(unsigned int id,
unsigned long drive_strength)
{
switch (id) {
case 0:
portmux_select_peripheral(PORTMUX_PORT_A, 1 << 30,
PORTMUX_FUNC_A, drive_strength);
break;
case 1:
portmux_select_peripheral(PORTMUX_PORT_A, 1 << 31,
PORTMUX_FUNC_A, drive_strength);
break;
case 2:
portmux_select_peripheral(PORTMUX_PORT_B, 1 << 19,
PORTMUX_FUNC_A, drive_strength);
break;
case 3:
portmux_select_peripheral(PORTMUX_PORT_B, 1 << 29,
PORTMUX_FUNC_A, drive_strength);
break;
case 4:
portmux_select_peripheral(PORTMUX_PORT_B, 1 << 30,
PORTMUX_FUNC_A, drive_strength);
break;
}
}
#endif /* __ASM_AVR32_ARCH_CLK_H__ */