From: Dave Gerlach <d-gerlach@xxxxxx>
Some boards (currently AM335x EVM-SK) provides s/w control via
GPIO to toggle VTT regulator to reduce power consumption in low
power state.
The VTT regulator should be disabled after enabling self-refresh on
suspend, and should be enabled before disabling self-refresh on resume.
This is to allow proper self-refresh entry/exit commands to be
transmitted to the memory.
Add support for toggling VTT regulator using DT properties.
Actual toggling happens in CM3 Firmware. The enable option & the GPIO
pin used is collected in A8 Core and then sent to CM3 using IPC
registers.
Note:
Here it is assumed that VTT Toggle will be done using a pin on GPIO-0
Instance. The reason is GPIO-0 is in wakeup domain.
Signed-off-by: Dave Gerlach <d-gerlach@xxxxxx>
Signed-off-by: Keerthy <j-keerthy@xxxxxx>
Signed-off-by: Drew Fustini <dfustini@xxxxxxxxxxxx>
---
drivers/soc/ti/wkup_m3_ipc.c | 27 +++++++++++++++++++++++++--
include/linux/wkup_m3_ipc.h | 1 +
2 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/drivers/soc/ti/wkup_m3_ipc.c b/drivers/soc/ti/wkup_m3_ipc.c
index 72386bd393fe..974b4118a893 100644
--- a/drivers/soc/ti/wkup_m3_ipc.c
+++ b/drivers/soc/ti/wkup_m3_ipc.c
@@ -40,6 +40,13 @@
#define M3_FW_VERSION_MASK 0xffff
#define M3_WAKE_SRC_MASK 0xff
+#define IPC_MEM_TYPE_SHIFT (0x0)
+#define IPC_MEM_TYPE_MASK (0x7 << 0)
+#define IPC_VTT_STAT_SHIFT (0x3)
+#define IPC_VTT_STAT_MASK (0x1 << 3)
+#define IPC_VTT_GPIO_PIN_SHIFT (0x4)
+#define IPC_VTT_GPIO_PIN_MASK (0x3f << 4)
+
#define M3_STATE_UNKNOWN 0
#define M3_STATE_RESET 1
#define M3_STATE_INITED 2
@@ -215,6 +222,12 @@ static int wkup_m3_is_available(struct wkup_m3_ipc *m3_ipc)
(m3_ipc->state != M3_STATE_UNKNOWN));
}
+static void wkup_m3_set_vtt_gpio(struct wkup_m3_ipc *m3_ipc, int gpio)
+{
+ m3_ipc->vtt_conf = (1 << IPC_VTT_STAT_SHIFT) |
+ (gpio << IPC_VTT_GPIO_PIN_SHIFT);
+}
+
/* Public functions */
/**
* wkup_m3_set_mem_type - Pass wkup_m3 which type of memory is in use
@@ -294,7 +307,8 @@ static int wkup_m3_prepare_low_power(struct wkup_m3_ipc *m3_ipc, int state)
/* Program each required IPC register then write defaults to others */
wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->resume_addr, 0);
wkup_m3_ctrl_ipc_write(m3_ipc, m3_power_state, 1);
- wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->mem_type, 4);
+ wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->mem_type |
+ m3_ipc->vtt_conf, 4);
wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 2);
wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 3);
@@ -433,12 +447,13 @@ static int wkup_m3_rproc_boot_thread(void *arg)
static int wkup_m3_ipc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
- int irq, ret;
+ int irq, ret, temp;
phandle rproc_phandle;
struct rproc *m3_rproc;
struct resource *res;
struct task_struct *task;
struct wkup_m3_ipc *m3_ipc;
+ struct device_node *np = dev->of_node;
m3_ipc = devm_kzalloc(dev, sizeof(*m3_ipc), GFP_KERNEL);
if (!m3_ipc)
@@ -496,6 +511,14 @@ static int wkup_m3_ipc_probe(struct platform_device *pdev)
m3_ipc->ops = &ipc_ops;
+ if (of_find_property(np, "ti,needs-vtt-toggle", NULL) &&
+ !(of_property_read_u32(np, "ti,vtt-gpio-pin", &temp))) {
+ if (temp >= 0 && temp <= 31)
+ wkup_m3_set_vtt_gpio(m3_ipc, temp);
+ else
+ dev_warn(dev, "Invalid VTT GPIO(%d) pin\n", temp);
+ }
+
/*
* Wait for firmware loading completion in a thread so we
* can boot the wkup_m3 as soon as it's ready without holding
diff --git a/include/linux/wkup_m3_ipc.h b/include/linux/wkup_m3_ipc.h
index 3f496967b538..2bc52c6381d5 100644
--- a/include/linux/wkup_m3_ipc.h
+++ b/include/linux/wkup_m3_ipc.h
@@ -33,6 +33,7 @@ struct wkup_m3_ipc {
int mem_type;
unsigned long resume_addr;
+ int vtt_conf;
int state;
struct completion sync_complete;
--
2.32.0
