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: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2013-07-09 10:27:12 +01:00
Родитель 374b105797
Коммит 7dde0c0328
2 изменённых файлов: 137 добавлений и 4 удалений

Просмотреть файл

@ -75,12 +75,143 @@ void ASSABET_BCR_frob(unsigned int mask, unsigned int val)
EXPORT_SYMBOL(ASSABET_BCR_frob); 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) static void assabet_ucb1x00_reset(enum ucb1x00_reset state)
{ {
if (state == UCB_RST_PROBE) int set = state == UCB_RST_REMOVE || state == UCB_RST_SUSPEND ||
ASSABET_BCR_set(ASSABET_BCR_CODEC_RST); 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);
/* /*
* Assabet flash support code. * Assabet flash support code.

Просмотреть файл

@ -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_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_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_NGFX_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_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_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_MD0 (1<<4) /* Range/Power select */
#define ASSABET_BCR_IRDA_MD1 (1<<5) /* 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) #define ASSABET_BCR_frob(x,y) do { } while (0)
#endif #endif
extern void assabet_uda1341_reset(int set);
#define ASSABET_BCR_set(x) ASSABET_BCR_frob((x), (x)) #define ASSABET_BCR_set(x) ASSABET_BCR_frob((x), (x))
#define ASSABET_BCR_clear(x) ASSABET_BCR_frob((x), 0) #define ASSABET_BCR_clear(x) ASSABET_BCR_frob((x), 0)