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Commit df8a95f4 authored by Wolfgang Grandegger's avatar Wolfgang Grandegger Committed by Grant Likely
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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: default avatarWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent bb899d49

arch/powerpc/include/asm/mpc52xx.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -273,6 +273,7 @@ extern void mpc5200_setup_xlb_arbiter(void); 
extern void mpc52xx_declare_of_platform_devices(void);

extern void mpc52xx_declare_of_platform_devices(void);

extern void mpc52xx_map_common_devices(void);

extern void mpc52xx_map_common_devices(void);

extern int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv);

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);

extern void mpc52xx_restart(char *cmd);





/* mpc52xx_pic.c */

/* mpc52xx_pic.c */

arch/powerpc/platforms/52xx/mpc52xx_common.c

+37 −0
Original line number Original line Diff line number Diff line
@@ -205,6 +205,43 @@ int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv) 
}

}

EXPORT_SYMBOL(mpc52xx_set_psc_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

 * mpc52xx_restart: ppc_md->restart hook for mpc5200 using the watchdog timer

 */

 */