ARM: at91/rtc-at91sam9: pass the GPBR to use via resources

The GPBR registers are used for storing RTC values. The GPBR registers
to use are now provided using standard resource entry. The array is
filled in SoC specific code.
rtc-at91sam9 RTT as RTC driver is modified to retrieve this information.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
[nicolas.ferre@atmel.com: rework resources assignment]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Reviewed-by: Ryan Mallon <rmallon@gmail.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/arch/arm/mach-at91/at91sam9g45_devices.c b/arch/arm/mach-at91/at91sam9g45_devices.c
index 81d1adf1d978..98e40418fda1 100644
--- a/arch/arm/mach-at91/at91sam9g45_devices.c
+++ b/arch/arm/mach-at91/at91sam9g45_devices.c
@@ -1194,6 +1194,8 @@ static struct resource rtt_resources[] = {
                 .start  = AT91SAM9G45_BASE_RTT,
                 .end    = AT91SAM9G45_BASE_RTT + SZ_16 - 1,
                 .flags  = IORESOURCE_MEM,
+        }, {
+                .flags  = IORESOURCE_MEM,
         }
 };
 
@@ -1201,16 +1203,27 @@ static struct platform_device at91sam9g45_rtt_device = {
         .name           = "at91_rtt",
         .id             = 0,
         .resource       = rtt_resources,
-        .num_resources  = ARRAY_SIZE(rtt_resources),
 };
 
 #if IS_ENABLED(CONFIG_RTC_DRV_AT91SAM9)
 static void __init at91_add_device_rtt_rtc(void)
 {
         at91sam9g45_rtt_device.name = "rtc-at91sam9";
+        /*
+         * The second resource is needed:
+         * GPBR will serve as the storage for RTC time offset
+         */
+        at91sam9g45_rtt_device.num_resources = 2;
+        rtt_resources[1].start = AT91SAM9G45_BASE_GPBR +
+                                 4 * CONFIG_RTC_DRV_AT91SAM9_GPBR;
+        rtt_resources[1].end = rtt_resources[1].start + 3;
 }
 #else
-static void __init at91_add_device_rtt_rtc(void) {}
+static void __init at91_add_device_rtt_rtc(void)
+{
+        /* Only one resource is needed: RTT not used as RTC */
+        at91sam9g45_rtt_device.num_resources = 1;
+}
 #endif
 
 static void __init at91_add_device_rtt(void)