diff options
| author | Wolfgang Grandegger <wg@grandegger.com> | 2009-03-11 09:36:26 -0600 |
|---|---|---|
| committer | Grant Likely <grant.likely@secretlab.ca> | 2009-03-11 09:36:26 -0600 |
| commit | df8a95f46f8e43a24003abe2efaca8c63c895b54 (patch) | |
| tree | cee931917b5bbc3e77d9b3e2ad3145856d8118b8 /arch/powerpc | |
| parent | bb899d49a5d04ae53c787c15c5fb82754d6a0da4 (diff) | |
powerpc/5200: add function to return external clock frequency
This patch adds the utility function mpc52xx_get_xtal_freq() to get
the frequency of the external oscillator clock connected to the pin
SYS_XTAL_IN. The MSCAN may us it as clock source. Unfortunately, this
value is not available from the FDT blob, but it can be determined
from the IPB frequency.
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/include/asm/mpc52xx.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/platforms/52xx/mpc52xx_common.c | 37 |
2 files changed, 38 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/mpc52xx.h b/arch/powerpc/include/asm/mpc52xx.h index 81a23932a160..52e049cd9e68 100644 --- a/arch/powerpc/include/asm/mpc52xx.h +++ b/arch/powerpc/include/asm/mpc52xx.h @@ -273,6 +273,7 @@ extern void mpc5200_setup_xlb_arbiter(void); extern void mpc52xx_declare_of_platform_devices(void); extern void mpc52xx_map_common_devices(void); extern int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv); +extern unsigned int mpc52xx_get_xtal_freq(struct device_node *node); extern void mpc52xx_restart(char *cmd); /* mpc52xx_pic.c */ diff --git a/arch/powerpc/platforms/52xx/mpc52xx_common.c b/arch/powerpc/platforms/52xx/mpc52xx_common.c index e9d2cf632eeb..8e3dd5a0f228 100644 --- a/arch/powerpc/platforms/52xx/mpc52xx_common.c +++ b/arch/powerpc/platforms/52xx/mpc52xx_common.c @@ -206,6 +206,43 @@ int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv) EXPORT_SYMBOL(mpc52xx_set_psc_clkdiv); /** + * mpc52xx_get_xtal_freq - Get SYS_XTAL_IN frequency for a device + * + * @node: device node + * + * Returns the frequency of the external oscillator clock connected + * to the SYS_XTAL_IN pin, or 0 if it cannot be determined. + */ +unsigned int mpc52xx_get_xtal_freq(struct device_node *node) +{ + u32 val; + unsigned int freq; + + if (!mpc52xx_cdm) + return 0; + + freq = mpc52xx_find_ipb_freq(node); + if (!freq) + return 0; + + if (in_8(&mpc52xx_cdm->ipb_clk_sel) & 0x1) + freq *= 2; + + val = in_be32(&mpc52xx_cdm->rstcfg); + if (val & (1 << 5)) + freq *= 8; + else + freq *= 4; + if (val & (1 << 6)) + freq /= 12; + else + freq /= 16; + + return freq; +} +EXPORT_SYMBOL(mpc52xx_get_xtal_freq); + +/** * mpc52xx_restart: ppc_md->restart hook for mpc5200 using the watchdog timer */ void |