Subject: libata: add ledtrig support
From: Daniel Golle <[email-masked]>

This adds a LED trigger for each ATA port indicating disk activity.

As this is needed only on specific platforms (NAS SoCs and such),
these platforms should define ARCH_WANTS_LIBATA_LEDS if there
are boards with LED(s) intended to indicate ATA disk activity and
need the OS to take care of that.
In that way, if not selected, LED trigger support not will be
included in libata-core and both, codepaths and structures remain
untouched.

Signed-off-by: Daniel Golle <[email-masked]>
---
 drivers/ata/Kconfig       | 16 ++++++++++++++++
 drivers/ata/libata-core.c | 41 +++++++++++++++++++++++++++++++++++++++++
 include/linux/libata.h    |  9 +++++++++
 3 files changed, 66 insertions(+)

--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -67,6 +67,22 @@ config ATA_FORCE
 
 	  If unsure, say Y.
 
+config ARCH_WANT_LIBATA_LEDS
+	bool
+
+config ATA_LEDS
+	bool "support ATA port LED triggers"
+	depends on ARCH_WANT_LIBATA_LEDS
+	select NEW_LEDS
+	select LEDS_CLASS
+	select LEDS_TRIGGERS
+	default y
+	help
+	  This option adds a LED trigger for each registered ATA port.
+	  It is used to drive disk activity leds connected via GPIO.
+
+	  If unsure, say N.
+
 config ATA_ACPI
 	bool "ATA ACPI Support"
 	depends on ACPI
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -650,6 +650,19 @@ u64 ata_tf_read_block(const struct ata_t
 	return block;
 }
 
+#ifdef CONFIG_ATA_LEDS
+#define LIBATA_BLINK_DELAY 20 /* ms */
+static inline void ata_led_act(struct ata_port *ap)
+{
+	unsigned long led_delay = LIBATA_BLINK_DELAY;
+
+	if (unlikely(!ap->ledtrig))
+		return;
+
+	led_trigger_blink_oneshot(ap->ledtrig, &led_delay, &led_delay, 0);
+}
+#endif
+
 /**
  *	ata_build_rw_tf - Build ATA taskfile for given read/write request
  *	@tf: Target ATA taskfile
@@ -4555,6 +4568,9 @@ struct ata_queued_cmd *ata_qc_new_init(s
 		if (tag < 0)
 			return NULL;
 	}
+#ifdef CONFIG_ATA_LEDS
+	ata_led_act(ap);
+#endif
 
 	qc = __ata_qc_from_tag(ap, tag);
 	qc->tag = qc->hw_tag = tag;
@@ -5333,6 +5349,9 @@ struct ata_port *ata_port_alloc(struct a
 	ap->stats.unhandled_irq = 1;
 	ap->stats.idle_irq = 1;
 #endif
+#ifdef CONFIG_ATA_LEDS
+	ap->ledtrig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
+#endif
 	ata_sff_port_init(ap);
 
 	return ap;
@@ -5368,6 +5387,12 @@ static void ata_host_release(struct kref
 
 		kfree(ap->pmp_link);
 		kfree(ap->slave_link);
+#ifdef CONFIG_ATA_LEDS
+		if (ap->ledtrig) {
+			led_trigger_unregister(ap->ledtrig);
+			kfree(ap->ledtrig);
+		};
+#endif
 		kfree(ap);
 		host->ports[i] = NULL;
 	}
@@ -5774,7 +5799,23 @@ int ata_host_register(struct ata_host *h
 		host->ports[i]->print_id = atomic_inc_return(&ata_print_id);
 		host->ports[i]->local_port_no = i + 1;
 	}
+#ifdef CONFIG_ATA_LEDS
+	for (i = 0; i < host->n_ports; i++) {
+		if (unlikely(!host->ports[i]->ledtrig))
+			continue;
 
+		snprintf(host->ports[i]->ledtrig_name,
+			sizeof(host->ports[i]->ledtrig_name), "ata%u",
+			host->ports[i]->print_id);
+
+		host->ports[i]->ledtrig->name = host->ports[i]->ledtrig_name;
+
+		if (led_trigger_register(host->ports[i]->ledtrig)) {
+			kfree(host->ports[i]->ledtrig);
+			host->ports[i]->ledtrig = NULL;
+		}
+	}
+#endif
 	/* Create associated sysfs transport objects  */
 	for (i = 0; i < host->n_ports; i++) {
 		rc = ata_tport_add(host->dev,host->ports[i]);
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -23,6 +23,9 @@
 #include <linux/cdrom.h>
 #include <linux/sched.h>
 #include <linux/async.h>
+#ifdef CONFIG_ATA_LEDS
+#include <linux/leds.h>
+#endif
 
 /*
  * Define if arch has non-standard setup.  This is a _PCI_ standard
@@ -887,6 +890,12 @@ struct ata_port {
 #ifdef CONFIG_ATA_ACPI
 	struct ata_acpi_gtm	__acpi_init_gtm; /* use ata_acpi_init_gtm() */
 #endif
+
+#ifdef CONFIG_ATA_LEDS
+	struct led_trigger	*ledtrig;
+	char			ledtrig_name[8];
+#endif
+
 	/* owned by EH */
 	u8			sector_buf[ATA_SECT_SIZE] ____cacheline_aligned;
 };