From: Thara Gopinath <thara@xxxxxx>
Voltage control on TWL can be done using VMODE/I2C1/I2C_SR.
Since almost all platforms use I2C_SR on omap3, omap3_twl_init by
default expects that OMAP's I2C_SR is plugged in to TWL's I2C
and calls omap3_twl_set_sr_bit. On platforms where I2C_SR is not connected,
the board files are expected to call omap3_twl_set_sr_bit(false) to
ensure that I2C_SR path is not set for voltage control and prevent
the default behavior of omap3_twl_init.
Signed-off-by: Nishanth Menon <nm@xxxxxx>
Signed-off-by: Thara Gopinath <thara@xxxxxx>
Signed-off-by: Shweta Gulati <shweta.gulati@xxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Kevin Hilman <khilman@xxxxxx>
---
arch/arm/mach-omap2/omap_twl.c | 60 ++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/arch/arm/mach-omap2/omap_twl.c b/arch/arm/mach-omap2/omap_twl.c
index 6787f1e72c6b..1dae906128c2 100644
--- a/arch/arm/mach-omap2/omap_twl.c
+++ b/arch/arm/mach-omap2/omap_twl.c
@@ -43,8 +43,15 @@
static bool is_offset_valid;
static u8 smps_offset;
+/*
+ * Flag to ensure Smartreflex bit in TWL
+ * being cleared in board file is not overwritten.
+ */
+static bool __initdata twl_sr_enable_autoinit;
+#define TWL4030_DCDC_GLOBAL_CFG 0x06
#define REG_SMPS_OFFSET 0xE0
+#define SMARTREFLEX_ENABLE BIT(3)
static unsigned long twl4030_vsel_to_uv(const u8 vsel)
{
@@ -241,6 +248,18 @@ int __init omap3_twl_init(void)
if (!cpu_is_omap34xx())
return -ENODEV;
+ /*
+ * The smartreflex bit on twl4030 specifies if the setting of voltage
+ * is done over the I2C_SR path. Since this setting is independent of
+ * the actual usage of smartreflex AVS module, we enable TWL SR bit
+ * by default irrespective of whether smartreflex AVS module is enabled
+ * on the OMAP side or not. This is because without this bit enabled,
+ * the voltage scaling through vp forceupdate/bypass mechanism of
+ * voltage scaling will not function on TWL over I2C_SR.
+ */
+ if (!twl_sr_enable_autoinit)
+ omap3_twl_set_sr_bit(true);
+
voltdm = voltdm_lookup("mpu_iva");
omap_voltage_register_pmic(voltdm, &omap3_mpu_pmic);
@@ -249,3 +268,44 @@ int __init omap3_twl_init(void)
return 0;
}
+
+/**
+ * omap3_twl_set_sr_bit() - Set/Clear SR bit on TWL
+ * @enable: enable SR mode in twl or not
+ *
+ * If 'enable' is true, enables Smartreflex bit on TWL 4030 to make sure
+ * voltage scaling through OMAP SR works. Else, the smartreflex bit
+ * on twl4030 is cleared as there are platforms which use OMAP3 and T2 but
+ * use Synchronized Scaling Hardware Strategy (ENABLE_VMODE=1) and Direct
+ * Strategy Software Scaling Mode (ENABLE_VMODE=0), for setting the voltages,
+ * in those scenarios this bit is to be cleared (enable = false).
+ *
+ * Returns 0 on sucess, error is returned if I2C read/write fails.
+ */
+int __init omap3_twl_set_sr_bit(bool enable)
+{
+ u8 temp;
+ int ret;
+ if (twl_sr_enable_autoinit)
+ pr_warning("%s: unexpected multiple calls\n", __func__);
+
+ ret = twl_i2c_read_u8(TWL_MODULE_PM_RECEIVER, &temp,
+ TWL4030_DCDC_GLOBAL_CFG);
+ if (ret)
+ goto err;
+
+ if (enable)
+ temp |= SMARTREFLEX_ENABLE;
+ else
+ temp &= ~SMARTREFLEX_ENABLE;
+
+ ret = twl_i2c_write_u8(TWL_MODULE_PM_RECEIVER, temp,
+ TWL4030_DCDC_GLOBAL_CFG);
+ if (!ret) {
+ twl_sr_enable_autoinit = true;
+ return 0;
+ }
+err:
+ pr_err("%s: Error access to TWL4030 (%d)\n", __func__, ret);
+ return ret;
+}
--
2.17.1
