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authorRussell King <rmk+kernel@arm.linux.org.uk>2013-07-09 13:27:12 +0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-12-13 02:59:15 +0400
commit7dde0c032869ea92206398ad5c538d01931e3947 (patch)
treecc85223cd5c247a1ef6cdc41aaf55d25a4293508 /arch/arm/mach-sa1100/assabet.c
parent374b105797c3d4f29c685f3be535c35f5689b30e (diff)
downloadlinux-7dde0c032869ea92206398ad5c538d01931e3947.tar.xz
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>
Diffstat (limited to 'arch/arm/mach-sa1100/assabet.c')
-rw-r--r--arch/arm/mach-sa1100/assabet.c135
1 files changed, 133 insertions, 2 deletions
diff --git a/arch/arm/mach-sa1100/assabet.c b/arch/arm/mach-sa1100/assabet.c
index c9808c684152..6a15354d43b8 100644
--- a/arch/arm/mach-sa1100/assabet.c
+++ b/arch/arm/mach-sa1100/assabet.c
@@ -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);
/*