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Commit 7dde0c03 authored by Russell King's avatar Russell King
Browse files

ARM: sa11x0: assabet: better reset handling 



The codec reset pin is connected to several peripherals.  When the
reset is released, unfortunately the ADV7171 powers itself up rather
than remaining in power-down mode.  As we don't have a driver for
this device, we end up needlessly consuming an additional 330mW.

Not only that but we should have a way to arbitrate the reset signal.

This patch provides that facility: we program the ADV7171 to sleep
mode whenever the reset is released, and we release the reset when
any one of the three peripherals requests the reset to be released.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 374b1057

arch/arm/mach-sa1100/assabet.c

+133 −2
Original line number Diff line number Diff line
@@ -75,11 +75,142 @@ void ASSABET_BCR_frob(unsigned int mask, unsigned int val) 


EXPORT_SYMBOL(ASSABET_BCR_frob);



/*

 * The codec reset goes to three devices, so we need to release

 * the rest when any one of these requests it.  However, that

 * causes the ADV7171 to consume around 100mA - more than half

 * the LCD-blanked power.

 *

 * With the ADV7171, LCD and backlight enabled, we go over

 * budget on the MAX846 Li-Ion charger, and if no Li-Ion battery

 * is connected, the Assabet crashes.

 */

#define RST_UCB1X00 (1 << 0)

#define RST_UDA1341 (1 << 1)

#define RST_ADV7171 (1 << 2)



#define SDA GPIO_GPIO(15)

#define SCK GPIO_GPIO(18)

#define MOD GPIO_GPIO(17)



static void adv7171_start(void)

{

	GPSR = SCK;

	udelay(1);

	GPSR = SDA;

	udelay(2);

	GPCR = SDA;

}



static void adv7171_stop(void)

{

	GPSR = SCK;

	udelay(2);

	GPSR = SDA;

	udelay(1);

}



static void adv7171_send(unsigned byte)

{

	unsigned i;



	for (i = 0; i < 8; i++, byte <<= 1) {

		GPCR = SCK;

		udelay(1);

		if (byte & 0x80)

			GPSR = SDA;

		else

			GPCR = SDA;

		udelay(1);

		GPSR = SCK;

		udelay(1);

	}

	GPCR = SCK;

	udelay(1);

	GPSR = SDA;

	udelay(1);

	GPDR &= ~SDA;

	GPSR = SCK;

	udelay(1);

	if (GPLR & SDA)

		printk(KERN_WARNING "No ACK from ADV7171\n");

	udelay(1);

	GPCR = SCK | SDA;

	udelay(1);

	GPDR |= SDA;

	udelay(1);

}



static void adv7171_write(unsigned reg, unsigned val)

{

	unsigned gpdr = GPDR;

	unsigned gplr = GPLR;



	ASSABET_BCR = BCR_value | ASSABET_BCR_AUDIO_ON;

	udelay(100);



	GPCR = SDA | SCK | MOD; /* clear L3 mode to ensure UDA1341 doesn't respond */

	GPDR = (GPDR | SCK | MOD) & ~SDA;

	udelay(10);

	if (!(GPLR & SDA))

		printk(KERN_WARNING "Something dragging SDA down?\n");

	GPDR |= SDA;



	adv7171_start();

	adv7171_send(0x54);

	adv7171_send(reg);

	adv7171_send(val);

	adv7171_stop();



	/* Restore GPIO state for L3 bus */

	GPSR = gplr & (SDA | SCK | MOD);

	GPCR = (~gplr) & (SDA | SCK | MOD);

	GPDR = gpdr;

}



static void adv7171_sleep(void)

{

	/* Put the ADV7171 into sleep mode */

	adv7171_write(0x04, 0x40);

}



static unsigned codec_nreset;



static void assabet_codec_reset(unsigned mask, int set)

{

	unsigned long flags;

	bool old;



	local_irq_save(flags);

	old = !codec_nreset;

	if (set)

		codec_nreset &= ~mask;

	else

		codec_nreset |= mask;



	if (old != !codec_nreset) {

		if (codec_nreset) {

			ASSABET_BCR_set(ASSABET_BCR_NCODEC_RST);

			adv7171_sleep();

		} else {

			ASSABET_BCR_clear(ASSABET_BCR_NCODEC_RST);

		}

	}

	local_irq_restore(flags);

}



static void assabet_ucb1x00_reset(enum ucb1x00_reset state)

{

	if (state == UCB_RST_PROBE)

		ASSABET_BCR_set(ASSABET_BCR_CODEC_RST);

	int set = state == UCB_RST_REMOVE || state == UCB_RST_SUSPEND ||

		state == UCB_RST_PROBE_FAIL;

	assabet_codec_reset(RST_UCB1X00, set);

}



void assabet_uda1341_reset(int set)

{

	assabet_codec_reset(RST_UDA1341, set);

}

EXPORT_SYMBOL(assabet_uda1341_reset);





/*

arch/arm/mach-sa1100/include/mach/assabet.h

+4 −2
Original line number Diff line number Diff line
@@ -39,8 +39,8 @@ extern unsigned long SCR_value; 


#define ASSABET_BCR_CF_PWR	(1<<0)	/* Compact Flash Power (1 = 3.3v, 0 = off) */

#define ASSABET_BCR_CF_RST	(1<<1)	/* Compact Flash Reset (1 = power up reset) */

#define ASSABET_BCR_GFX_RST	(1<<1)	/* Graphics Accelerator Reset (0 = hold reset) */

#define ASSABET_BCR_CODEC_RST	(1<<2)	/* 0 = Holds UCB1300, ADI7171, and UDA1341 in reset */

#define ASSABET_BCR_NGFX_RST	(1<<1)	/* Graphics Accelerator Reset (0 = hold reset) */

#define ASSABET_BCR_NCODEC_RST	(1<<2)	/* 0 = Holds UCB1300, ADI7171, and UDA1341 in reset */

#define ASSABET_BCR_IRDA_FSEL	(1<<3)	/* IRDA Frequency select (0 = SIR, 1 = MIR/ FIR) */

#define ASSABET_BCR_IRDA_MD0	(1<<4)	/* Range/Power select */

#define ASSABET_BCR_IRDA_MD1	(1<<5)	/* Range/Power select */
@@ -69,6 +69,8 @@ extern void ASSABET_BCR_frob(unsigned int mask, unsigned int set); 
#define ASSABET_BCR_frob(x,y)	do { } while (0)

#endif



extern void assabet_uda1341_reset(int set);



#define ASSABET_BCR_set(x)	ASSABET_BCR_frob((x), (x))

#define ASSABET_BCR_clear(x)	ASSABET_BCR_frob((x), 0)