ARM: OMAP2+: Fix omap off idle power consumption creeping up

If we use a combination of VMODE and I2C4 for retention modes,
eventually the off idle power consumption will creep up by about
23mW, even during off mode with I2C4 always staying enabled.

Turns out this is because of erratum i531 "Extra Power Consumed
When Repeated Start Operation Mode Is Enabled on I2C Interface
Dedicated for Smart Reflex (I2C4)" as pointed out by Nishanth
Menon <nm@ti.com>.

Let's fix the issue by adding i2c_cfg_clear_mask for the bits
to clear when initializing the I2C4 adapter so we can clear
SREN bit that drives the I2C4 lines low otherwise when there
is no traffic.

Fixes: 3b8c4ebb7630 ("ARM: OMAP3: Fix idle mode signaling for
Cc: stable@vger.kernel.org # v3.16+
sys_clkreq and sys_off_mode")
Cc: Kevin Hilman <khilman@kernel.org>
Cc: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

diff --git a/arch/arm/mach-omap2/prm-regbits-34xx.h b/arch/arm/mach-omap2/prm-regbits-34xx.h
index cbefbd7cfdb5c02da2a9815f9662fe75879fe969..661d753df58469ecc84081ca3e2eef075de7d3cb 100644 (file)
--- a/arch/arm/mach-omap2/prm-regbits-34xx.h
+++ b/arch/arm/mach-omap2/prm-regbits-34xx.h
@@ -112,6 +112,7 @@
 #define OMAP3430_VC_CMD_ONLP_SHIFT                     16
 #define OMAP3430_VC_CMD_RET_SHIFT                      8
 #define OMAP3430_VC_CMD_OFF_SHIFT                      0
+#define OMAP3430_SREN_MASK                             (1 << 4)
 #define OMAP3430_HSEN_MASK                             (1 << 3)
 #define OMAP3430_MCODE_MASK                            (0x7 << 0)
 #define OMAP3430_VALID_MASK                            (1 << 24)

diff --git a/arch/arm/mach-omap2/prm-regbits-44xx.h b/arch/arm/mach-omap2/prm-regbits-44xx.h
index b1c7a33e00e74c36369b641a14c912110e17a23c..e794828dee553b2e943bc74b4ae819874c40455e 100644 (file)
--- a/arch/arm/mach-omap2/prm-regbits-44xx.h
+++ b/arch/arm/mach-omap2/prm-regbits-44xx.h
@@ -35,6 +35,7 @@
 #define OMAP4430_GLOBAL_WARM_SW_RST_SHIFT                              1
 #define OMAP4430_GLOBAL_WUEN_MASK                                      (1 << 16)
 #define OMAP4430_HSMCODE_MASK                                          (0x7 << 0)
+#define OMAP4430_SRMODEEN_MASK                                         (1 << 4)
 #define OMAP4430_HSMODEEN_MASK                                         (1 << 3)
 #define OMAP4430_HSSCLL_SHIFT                                          24
 #define OMAP4430_ICEPICK_RST_SHIFT                                     9

diff --git a/arch/arm/mach-omap2/vc.c b/arch/arm/mach-omap2/vc.c
index be9ef834fa81d56666f247dae2a598ef422ee15d..076fd20d7e5aa03adfa9d14ec15293e374ceaace 100644 (file)
--- a/arch/arm/mach-omap2/vc.c
+++ b/arch/arm/mach-omap2/vc.c
@@ -316,7 +316,8 @@ static void __init omap3_vc_init_pmic_signaling(struct voltagedomain *voltdm)
         * idle. And we can also scale voltages to zero for off-idle.
         * Note that no actual voltage scaling during off-idle will
         * happen unless the board specific twl4030 PMIC scripts are
-        * loaded.
+        * loaded. See also omap_vc_i2c_init for comments regarding
+        * erratum i531.
         */
        val = voltdm->read(OMAP3_PRM_VOLTCTRL_OFFSET);
        if (!(val & OMAP3430_PRM_VOLTCTRL_SEL_OFF)) {
@@ -704,9 +705,16 @@ static void __init omap_vc_i2c_init(struct voltagedomain *voltdm)
                return;
        }
 
+       /*
+        * Note that for omap3 OMAP3430_SREN_MASK clears SREN to work around
+        * erratum i531 "Extra Power Consumed When Repeated Start Operation
+        * Mode Is Enabled on I2C Interface Dedicated for Smart Reflex (I2C4)".
+        * Otherwise I2C4 eventually leads into about 23mW extra power being
+        * consumed even during off idle using VMODE.
+        */
        i2c_high_speed = voltdm->pmic->i2c_high_speed;
        if (i2c_high_speed)
-               voltdm->rmw(vc->common->i2c_cfg_hsen_mask,
+               voltdm->rmw(vc->common->i2c_cfg_clear_mask,
                            vc->common->i2c_cfg_hsen_mask,
                            vc->common->i2c_cfg_reg);
 

diff --git a/arch/arm/mach-omap2/vc.h b/arch/arm/mach-omap2/vc.h
index cdbdd78e755e2c60347ca66ca378d5895a9ab87e..89b83b7ff3ec5c34d4906f1504700c45c6a00abc 100644 (file)
--- a/arch/arm/mach-omap2/vc.h
+++ b/arch/arm/mach-omap2/vc.h
@@ -34,6 +34,7 @@ struct voltagedomain;
  * @cmd_ret_shift: RET field shift in PRM_VC_CMD_VAL_* register
  * @cmd_off_shift: OFF field shift in PRM_VC_CMD_VAL_* register
  * @i2c_cfg_reg: I2C configuration register offset
+ * @i2c_cfg_clear_mask: high-speed mode bit clear mask in I2C config register
  * @i2c_cfg_hsen_mask: high-speed mode bit field mask in I2C config register
  * @i2c_mcode_mask: MCODE field mask for I2C config register
  *
@@ -52,6 +53,7 @@ struct omap_vc_common {
        u8 cmd_ret_shift;
        u8 cmd_off_shift;
        u8 i2c_cfg_reg;
+       u8 i2c_cfg_clear_mask;
        u8 i2c_cfg_hsen_mask;
        u8 i2c_mcode_mask;
 };

diff --git a/arch/arm/mach-omap2/vc3xxx_data.c b/arch/arm/mach-omap2/vc3xxx_data.c
index 75bc4aa22b3a0963d0e6ed468fecc5e17257eef4..71d74c9172c15f0169203be438f6756b0a164965 100644 (file)
--- a/arch/arm/mach-omap2/vc3xxx_data.c
+++ b/arch/arm/mach-omap2/vc3xxx_data.c
@@ -40,6 +40,7 @@ static struct omap_vc_common omap3_vc_common = {
        .cmd_onlp_shift  = OMAP3430_VC_CMD_ONLP_SHIFT,
        .cmd_ret_shift   = OMAP3430_VC_CMD_RET_SHIFT,
        .cmd_off_shift   = OMAP3430_VC_CMD_OFF_SHIFT,
+       .i2c_cfg_clear_mask = OMAP3430_SREN_MASK | OMAP3430_HSEN_MASK,
        .i2c_cfg_hsen_mask = OMAP3430_HSEN_MASK,
        .i2c_cfg_reg     = OMAP3_PRM_VC_I2C_CFG_OFFSET,
        .i2c_mcode_mask  = OMAP3430_MCODE_MASK,

diff --git a/arch/arm/mach-omap2/vc44xx_data.c b/arch/arm/mach-omap2/vc44xx_data.c
index 085e5d6a04fd088c5422235478bb012861a96078..2abd5fa8a6972d2a435735c6419f750fbb37b567 100644 (file)
--- a/arch/arm/mach-omap2/vc44xx_data.c
+++ b/arch/arm/mach-omap2/vc44xx_data.c
@@ -42,6 +42,7 @@ static const struct omap_vc_common omap4_vc_common = {
        .cmd_ret_shift = OMAP4430_RET_SHIFT,
        .cmd_off_shift = OMAP4430_OFF_SHIFT,
        .i2c_cfg_reg = OMAP4_PRM_VC_CFG_I2C_MODE_OFFSET,
+       .i2c_cfg_clear_mask = OMAP4430_SRMODEEN_MASK | OMAP4430_HSMODEEN_MASK,
        .i2c_cfg_hsen_mask = OMAP4430_HSMODEEN_MASK,
        .i2c_mcode_mask  = OMAP4430_HSMCODE_MASK,
 };