This patch adds the ability to write an I2C sleep sequence from
SRAM just before WFI, and a wake sequence just after control is passed
from the M3. This is useful for adjusting voltages during sleep that cannot
be lowered while SDRAM is active.
Each sequence is a series of I2C transfers in the form:
u8 length | u8 chip address | u8 byte0/reg address | u8 byte 1 | u8 byte n ...
The length indicates the number of bytes to transfer, including the register
address. The length of the sequence is limited by the amount of space
reserved in SRAM, 127 bytes.
The sequences are taken from the i2c1 node in the device tree. The property
name for the sleep sequence is "sleep_sequence" and the property name for
the wake sequence is "wake_sequence". Each property should be an array of
bytes.
No actions are performed if the properties are not present in the device
tree.
Signed-off-by: Russ Dill <Russ.Dill@xxxxxx>
---
arch/arm/mach-omap2/pm33xx.c | 108 +++++++++++++++++++++++
arch/arm/mach-omap2/pm33xx.h | 23 +++++
arch/arm/mach-omap2/sleep33xx.S | 184 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 315 insertions(+)
diff --git a/arch/arm/mach-omap2/pm33xx.c b/arch/arm/mach-omap2/pm33xx.c
index 93f970f..8aeaf6e 100644
--- a/arch/arm/mach-omap2/pm33xx.c
+++ b/arch/arm/mach-omap2/pm33xx.c
@@ -47,10 +47,14 @@
void (*am33xx_do_wfi_sram)(void);
static void __iomem *am33xx_emif_base;
+static void __iomem *am33xx_i2c1_base;
static struct powerdomain *cefuse_pwrdm, *gfx_pwrdm, *per_pwrdm;
static struct clockdomain *gfx_l4ls_clkdm;
static struct omap_hwmod *usb_oh, *cpsw_oh, *tptc0_oh, *tptc1_oh, *tptc2_oh;
+static struct omap_hwmod *i2c1_oh;
static struct wkup_m3_context *wkup_m3;
+static char *am33xx_i2c_sleep_sequence;
+static char *am33xx_i2c_wake_sequence;
static DECLARE_COMPLETION(wkup_m3_sync);
@@ -88,7 +92,10 @@ static int am33xx_pm_suspend(void)
/* Try to put GFX to sleep */
pwrdm_set_next_fpwrst(gfx_pwrdm, PWRDM_FUNC_PWRST_OFF);
+ /* We need I2C to send the sleep/wake sequences */
+ omap_hwmod_enable(i2c1_oh);
ret = cpu_suspend(0, am33xx_do_sram_idle);
+ omap_hwmod_idle(i2c1_oh);
status = pwrdm_read_fpwrst(gfx_pwrdm);
if (status != PWRDM_FUNC_PWRST_OFF)
@@ -403,6 +410,101 @@ void __iomem *am33xx_get_emif_base(void)
return am33xx_emif_base;
}
+void am33xx_fill_i2c_sequences(char *sleep, size_t ssz, char *wake, size_t wsz)
+{
+ if (am33xx_i2c_sleep_sequence)
+ memcpy(sleep, am33xx_i2c_sleep_sequence, ssz);
+ else
+ memset(sleep, 0, ssz);
+
+ if (am33xx_i2c_wake_sequence)
+ memcpy(wake, am33xx_i2c_wake_sequence, wsz);
+ else
+ memset(wake, 0, wsz);
+}
+
+static int __init am33xx_map_i2c1(void)
+{
+ am33xx_i2c1_base = ioremap(AM33XX_I2C0_BASE, SZ_4K);
+
+ if (!am33xx_i2c1_base)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void __iomem *am33xx_get_i2c1_base(void)
+{
+ return am33xx_i2c1_base;
+}
+
+static int __init am33xx_setup_sleep_sequence(void)
+{
+ int ret;
+ int sz;
+ const void *prop;
+ struct device *dev;
+ struct omap_hwmod *oh;
+
+ ret = am33xx_map_i2c1();
+ if (ret) {
+ pr_err("Could not ioremap i2c1\n");
+ return ret;
+ }
+
+ oh = omap_hwmod_lookup("i2c1");
+ if (!oh)
+ return -ENODEV;
+
+ /*
+ * We put the device tree node in the I2C controller that will
+ * be sending the sequence.
+ */
+ dev = omap_device_get_by_hwmod_name("i2c1");
+ if (IS_ERR(dev))
+ return PTR_ERR(dev);
+
+ prop = of_get_property(dev->of_node, "sleep_sequence", &sz);
+ if (prop) {
+ if (sz >= i2c_sleep_sequence_sz) {
+ pr_err("Sleep sequence too long\n");
+ return -EINVAL;
+ }
+ am33xx_i2c_sleep_sequence = kzalloc(i2c_sleep_sequence_sz,
+ GFP_KERNEL);
+ if (!am33xx_i2c_sleep_sequence)
+ return -ENOMEM;
+ memcpy(am33xx_i2c_sleep_sequence, prop, sz);
+ }
+
+ prop = of_get_property(dev->of_node, "wake_sequence", &sz);
+ if (prop) {
+ if (sz >= i2c_wake_sequence_sz) {
+ pr_err("Wake sequence too long\n");
+ ret = -EINVAL;
+ goto cleanup_sleep;
+ }
+ am33xx_i2c_wake_sequence = kzalloc(i2c_wake_sequence_sz,
+ GFP_KERNEL);
+ if (!am33xx_i2c_wake_sequence) {
+ ret = -ENOMEM;
+ goto cleanup_sleep;
+ }
+ memcpy(am33xx_i2c_wake_sequence, prop, sz);
+ }
+
+ /* Only take the I2C controller out of idle if a sequence exists */
+ if (am33xx_i2c_sleep_sequence || am33xx_i2c_wake_sequence)
+ i2c1_oh = oh;
+
+ return 0;
+
+cleanup_sleep:
+ kfree(am33xx_i2c_sleep_sequence);
+ am33xx_i2c_sleep_sequence = NULL;
+ return ret;
+}
+
int __init am33xx_pm_init(void)
{
int ret;
@@ -449,6 +551,12 @@ int __init am33xx_pm_init(void)
goto err;
}
+ ret = am33xx_setup_sleep_sequence();
+ if (ret) {
+ pr_err("Error fetching I2C sleep/wake sequence\n");
+ goto err;
+ }
+
(void) clkdm_for_each(omap_pm_clkdms_setup, NULL);
/* CEFUSE domain can be turned off post bootup */
diff --git a/arch/arm/mach-omap2/pm33xx.h b/arch/arm/mach-omap2/pm33xx.h
index 13a2c85..69616ee 100644
--- a/arch/arm/mach-omap2/pm33xx.h
+++ b/arch/arm/mach-omap2/pm33xx.h
@@ -28,6 +28,9 @@ struct wkup_m3_context {
u8 state;
};
+extern u32 i2c_sleep_sequence_sz;
+extern u32 i2c_wake_sequence_sz;
+
#ifdef CONFIG_SUSPEND
static void am33xx_m3_state_machine_reset(void);
#else
@@ -52,5 +55,25 @@ extern void __iomem *am33xx_get_emif_base(void);
#define AM33XX_OCMC_END 0x40310000
#define AM33XX_EMIF_BASE 0x4C000000
+#define AM33XX_I2C0_BASE 0x44E0B000
+
+#define OMAP_I2C_STAT_BB (1 << 12)
+#define OMAP_I2C_STAT_ARDY (1 << 2)
+#define OMAP_I2C_STAT_NACK (1 << 1)
+#define OMAP_I2C_STAT_AL (1 << 0)
+
+#define OMAP_I2C_CON_EN (1 << 15)
+#define OMAP_I2C_CON_MST (1 << 10)
+#define OMAP_I2C_CON_TRX (1 << 9)
+#define OMAP_I2C_CON_STP (1 << 1)
+#define OMAP_I2C_CON_STT (1 << 0)
+
+#define OMAP_I2C_STAT_RAW_REG 0x24
+#define OMAP_I2C_STAT_REG 0x28
+#define OMAP_I2C_IRQENABLE_CLR 0x30
+#define OMAP_I2C_CNT_REG 0x98
+#define OMAP_I2C_DATA_REG 0x9c
+#define OMAP_I2C_CON_REG 0xa4
+#define OMAP_I2C_SA_REG 0xac
#endif
diff --git a/arch/arm/mach-omap2/sleep33xx.S b/arch/arm/mach-omap2/sleep33xx.S
index 98fa76c..85453e8 100644
--- a/arch/arm/mach-omap2/sleep33xx.S
+++ b/arch/arm/mach-omap2/sleep33xx.S
@@ -95,6 +95,19 @@ ENTRY(am33xx_do_wfi)
/* Save it for later use */
str r0, emif_addr_virt
+ /* Get/save the i2c1 base virtual address */
+ ldr r0, i2c_addr_func
+ blx r0
+ str r0, i2c_addr_virt
+
+ /* Load the sleep/wake sequences */
+ ldr r4, i2c_sequence_func
+ adrl r0, i2c_sleep_sequence
+ ldr r1, i2c_sleep_sequence_sz
+ adrl r2, i2c_wake_sequence
+ ldr r3, i2c_sleep_sequence_sz
+ blx r4
+
/* This ensures isb */
ldr r0, dcache_flush
blx r0
@@ -187,6 +200,10 @@ put_pll_bypass:
pll_bypass per, virt_per_clk_mode, virt_per_idlest, per_val
pll_bypass mpu, virt_mpu_clk_mode, virt_mpu_idlest, mpu_val
+ /* Write the sleep sequence, abort on suspend on error */
+ bl am33xx_i2c_write_sleep
+ bne wfi_abort
+
dsb
dmb
isb
@@ -209,6 +226,8 @@ put_pll_bypass:
nop
/* We come here in case of an abort due to a late interrupt */
+wfi_abort:
+ bl am33xx_i2c_write_wake
/* Set MPU_CLKCTRL.MODULEMODE back to ENABLE */
ldr r1, virt_mpu_clkctrl
@@ -312,6 +331,9 @@ ENTRY(am33xx_resume_offset)
.word . - am33xx_do_wfi
ENTRY(am33xx_resume_from_deep_sleep)
+
+ bl am33xx_i2c_write_wake
+
/* Take the PLLs out of LP_BYPASS */
pll_lock mpu, phys_mpu_clk_mode, phys_mpu_idlest, mpu_val
pll_lock per, phys_per_clk_mode, phys_per_idlest, per_val
@@ -415,6 +437,87 @@ wait_resume:
ldr pc, resume_addr
ENDPROC(am33xx_resume_from_deep_sleep)
+am33xx_i2c_write_wake:
+ adrl r3, i2c_wake_sequence
+ ldr r2, i2c_addr_phys
+ b am33xx_i2c_write
+
+am33xx_i2c_write_sleep:
+ adrl r3, i2c_sleep_sequence
+ ldr r2, i2c_addr_virt
+
+am33xx_i2c_write:
+ /* Early out check, don't touch the hardware */
+ ldrb r4, [r3]
+ tst r4, r4
+ moveq pc, lr
+
+ /* Disable all event interrupts */
+ movw r5, #0xffff
+ strh r5, [r2, #OMAP_I2C_IRQENABLE_CLR]
+
+i2c_transfer:
+ /* Ack all events */
+ strh r5, [r2, #OMAP_I2C_STAT_REG]
+
+ /*
+ * Loop through the I2C transfer list, a zero byte transfer
+ * terminates the list.
+ */
+ ldrb r4, [r3], #1
+ tst r4, r4
+ moveq pc, lr
+
+ /* Wait for bus to be ready */
+ mov r0, #1000
+1: ldr r1, [r2, #OMAP_I2C_STAT_RAW_REG]
+ tst r1, #OMAP_I2C_STAT_BB
+ beq bb_cleared
+ subs r0, r0, #1
+ bne 1b
+ b i2c_err
+
+bb_cleared:
+ /* Ack all events */
+ strh r5, [r2, #OMAP_I2C_STAT_REG]
+
+ /* Program I2C target address */
+ ldrb r1, [r3], #1
+ strh r1, [r2, #OMAP_I2C_SA_REG]
+
+ /* Store the length of the transfer */
+ strh r4, [r2, #OMAP_I2C_CNT_REG]
+
+ /* Configure I2C controller for transfer */
+ movw r1, #(OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_TRX | \
+ OMAP_I2C_CON_STP | OMAP_I2C_CON_STT)
+ strh r1, [r2, #OMAP_I2C_CON_REG]
+
+ /* Ack all events */
+ strh r5, [r2, #OMAP_I2C_STAT_REG]
+
+ /* Write out data */
+1: ldrb r1, [r3], #1
+ strh r1, [r2, #OMAP_I2C_DATA_REG]
+ subs r4, r4, #1
+ bne 1b
+
+ /* Wait for transfer to complete */
+ mov r0, #1000
+1: ldr r1, [r2, #OMAP_I2C_STAT_RAW_REG]
+ tst r1, #OMAP_I2C_STAT_NACK
+ tsteq r1, #OMAP_I2C_STAT_AL
+ bne i2c_err
+ tst r1, #OMAP_I2C_STAT_ARDY
+ bne i2c_transfer
+ subs r0, r0, #1
+ bne 1b
+
+i2c_err:
+ /* ACK all events and return NE */
+ strh r5, [r2, #OMAP_I2C_STAT_REG]
+ movs r0, #1
+ mov pc, lr
/*
* Local variables
@@ -578,6 +681,87 @@ clk_mode_ddr_val:
clk_mode_core_val:
.word 0xDEADBEEF
+i2c_addr_func:
+ .word am33xx_get_i2c1_base
+i2c_addr_virt:
+ .word 0xDEADBEEF
+i2c_addr_phys:
+ .word AM33XX_I2C0_BASE
+
+/* I2C sleep/wake sequence data */
+i2c_sleep_sequence:
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ENTRY(i2c_sleep_sequence_sz)
+ .word . - i2c_sleep_sequence
+i2c_wake_sequence:
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ .word 0xDEADBEEF
+ENTRY(i2c_wake_sequence_sz)
+ .word . - i2c_wake_sequence
+i2c_sequence_func:
+ .word am33xx_fill_i2c_sequences
+
.align 3
ENTRY(am33xx_do_wfi_sz)
.word . - am33xx_do_wfi
--
1.8.1.2
--
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