mfd: dbx500: Provide a more accurate smp_twd clock
The local timer clock is based on ARM subsystem clock. This patch
obtains a more exact value of that clock by reading PRCMU registers.
Using this increases the accuracy of the local timer events.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rickard Andersson <rickard.andersson@stericsson.com>
Signed-off-by: Michel Jaouen <michel.jaouen@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
diff --git a/drivers/mfd/db8500-prcmu.c b/drivers/mfd/db8500-prcmu.c
index 7040a00..6b37e2d 100644
--- a/drivers/mfd/db8500-prcmu.c
+++ b/drivers/mfd/db8500-prcmu.c
@@ -418,6 +418,9 @@
static atomic_t ac_wake_req_state = ATOMIC_INIT(0);
+/* Functions definition */
+static void compute_armss_rate(void);
+
/* Spinlocks */
static DEFINE_SPINLOCK(prcmu_lock);
static DEFINE_SPINLOCK(clkout_lock);
@@ -517,6 +520,7 @@
}
};
+
/*
* Used by MCDE to setup all necessary PRCMU registers
*/
@@ -1013,6 +1017,7 @@
(mb1_transfer.ack.arm_opp != opp))
r = -EIO;
+ compute_armss_rate();
mutex_unlock(&mb1_transfer.lock);
return r;
@@ -1612,6 +1617,7 @@
if ((branch == PLL_FIX) || ((branch == PLL_DIV) &&
(val & PRCM_PLL_FREQ_DIV2EN) &&
((reg == PRCM_PLLSOC0_FREQ) ||
+ (reg == PRCM_PLLARM_FREQ) ||
(reg == PRCM_PLLDDR_FREQ))))
div *= 2;
@@ -1661,6 +1667,39 @@
else
return 0;
}
+static unsigned long latest_armss_rate;
+static unsigned long armss_rate(void)
+{
+ return latest_armss_rate;
+}
+
+static void compute_armss_rate(void)
+{
+ u32 r;
+ unsigned long rate;
+
+ r = readl(PRCM_ARM_CHGCLKREQ);
+
+ if (r & PRCM_ARM_CHGCLKREQ_PRCM_ARM_CHGCLKREQ) {
+ /* External ARMCLKFIX clock */
+
+ rate = pll_rate(PRCM_PLLDDR_FREQ, ROOT_CLOCK_RATE, PLL_FIX);
+
+ /* Check PRCM_ARM_CHGCLKREQ divider */
+ if (!(r & PRCM_ARM_CHGCLKREQ_PRCM_ARM_DIVSEL))
+ rate /= 2;
+
+ /* Check PRCM_ARMCLKFIX_MGT divider */
+ r = readl(PRCM_ARMCLKFIX_MGT);
+ r &= PRCM_CLK_MGT_CLKPLLDIV_MASK;
+ rate /= r;
+
+ } else {/* ARM PLL */
+ rate = pll_rate(PRCM_PLLARM_FREQ, ROOT_CLOCK_RATE, PLL_DIV);
+ }
+
+ latest_armss_rate = rate;
+}
static unsigned long dsiclk_rate(u8 n)
{
@@ -1707,6 +1746,8 @@
return pll_rate(PRCM_PLLSOC0_FREQ, ROOT_CLOCK_RATE, PLL_RAW);
else if (clock == PRCMU_PLLSOC1)
return pll_rate(PRCM_PLLSOC1_FREQ, ROOT_CLOCK_RATE, PLL_RAW);
+ else if (clock == PRCMU_ARMSS)
+ return armss_rate();
else if (clock == PRCMU_PLLDDR)
return pll_rate(PRCM_PLLDDR_FREQ, ROOT_CLOCK_RATE, PLL_RAW);
else if (clock == PRCMU_PLLDSI)
@@ -2693,6 +2734,7 @@
handle_simple_irq);
set_irq_flags(irq, IRQF_VALID);
}
+ compute_armss_rate();
}
static void __init init_prcm_registers(void)
