msm: cpr: Add margin and range for step quot
Based on chip characterization data, it is good to add some
margin on top of calculated step quot to help reduce the
number of CPR interrupts. The present value suggested is 3.
Further, if the step quot is outside range, clamp it to the
maximum permitted value.
Change-Id: Ibe161a9b4ea69b78e16cdaa70daa81ae8acc34a0
Signed-off-by: Kaushal Kumar <kaushalk@codeaurora.org>
diff --git a/arch/arm/mach-msm/msm_cpr.c b/arch/arm/mach-msm/msm_cpr.c
index e2640a2..7ad63f4 100644
--- a/arch/arm/mach-msm/msm_cpr.c
+++ b/arch/arm/mach-msm/msm_cpr.c
@@ -44,6 +44,8 @@
*/
#define TIMER_COUNT(freq, delay) ((freq * delay) / 1000)
#define ALL_CPR_IRQ 0x3F
+#define STEP_QUOT_MAX 25
+#define STEP_QUOT_MIN 12
/* Need platform device handle for suspend and resume APIs */
static struct platform_device *cpr_pdev;
@@ -269,8 +271,19 @@
goto err_poll_result;
}
quot2 = (cpr_read_reg(cpr, RBCPR_DEBUG1) & QUOT_SLOW_M) >> 12;
- chip_data->step_quot = (quot1 - quot2) / 4;
- pr_info("%s: Calculated Step Quot is %d\n",
+ /*
+ * Based on chip characterization data, it is good to add some
+ * margin on top of calculated step quot to help reduce the
+ * number of CPR interrupts. The present value suggested is 3.
+ * Further, if the step quot is outside range, clamp it to the
+ * maximum permitted value.
+ */
+ chip_data->step_quot = ((quot1 - quot2) / 4) + 3;
+ if (chip_data->step_quot < STEP_QUOT_MIN ||
+ chip_data->step_quot > STEP_QUOT_MAX)
+ chip_data->step_quot = STEP_QUOT_MAX;
+
+ pr_info("%s: Step Quot is %d\n",
__func__, chip_data->step_quot);
/* Disable the cpr */
cpr_modify_reg(cpr, RBCPR_CTL, LOOP_EN_M, DISABLE_CPR);