Hi,

On 08/19/2014 11:33 AM, Tuomas Tynkkynen wrote:

From: Tuomas Tynkkynen <redacted>

With closed loop support, the clock rate of the DFLL can be adjusted.

The oscillator itself in the DFLL is a free-running oscillator whose
rate is directly determined the supply voltage. However, the DFLL
module contains logic to compare the DFLL output rate to a fixed
reference clock (51 MHz) and make a decision to either lower or raise
the DFLL supply voltage. The DFLL module can then autonomously change
the supply voltage by communicating with an off-chip PMIC via either I2C
or PWM signals. This driver currently supports only I2C.

Signed-off-by: Tuomas Tynkkynen <redacted>

---
v3: Fix incorrect order of arguments to dfll_scale_dvco_rate
---
  drivers/clk/tegra/clk-dfll.c | 656 ++++++++++++++++++++++++++++++++++++++++++-
  1 file changed, 653 insertions(+), 3 deletions(-)

...

+
+/**
+ * dfll_init_out_if - prepare DFLL-to-PMIC interface
+ * @td: DFLL instance
+ *
+ * During DFLL driver initialization or resume from context loss,
+ * disable the I2C command output to the PMIC, set safe voltage and
+ * output limits, and disable and clear limit interrupts.
+ */
+static void dfll_init_out_if(struct tegra_dfll *td)
+{
+	u32 val;
+
+	td->lut_min = 0;
+	td->lut_max = td->i2c_lut_size - 1;
+	td->lut_safe = td->lut_min + 1;
+
+	dfll_i2c_writel(td, 0, DFLL_OUTPUT_CFG);
+	val = (td->lut_safe << DFLL_OUTPUT_CFG_SAFE_SHIFT) |
+		(td->lut_max << DFLL_OUTPUT_CFG_MAX_SHIFT) |
+		(td->lut_min << DFLL_OUTPUT_CFG_MIN_SHIFT);
+	dfll_writel(td, val, DFLL_OUTPUT_CFG);
+	dfll_wmb(td);

Sorry that I forgot to mention this in v2's comment. Could you squash 
the change below in this patch? And actually it's pretty easy to misuse 
the dfll read/write/wmb functions. We might want to have some generic 
functions for these, and let the generic functions handle the offset to 
different register blocks.

commit 4a1fdd54141b4f8f9425d54cdad13c42763e6186
Author: Vince Hsu [off-list ref]
Date:   Thu Aug 14 18:19:20 2014 +0800

     clk: tegra: use the correct write funtion for DFLL_OUTPUT_CFG

     Signed-off-by: Vince Hsu [off-list ref]

diff --git a/drivers/clk/tegra/clk-dfll.c b/drivers/clk/tegra/clk-dfll.c
index 9b3eded6b880..71e4b256ea0d 100644
--- a/drivers/clk/tegra/clk-dfll.c
+++ b/drivers/clk/tegra/clk-dfll.c

@@ -645,7 +645,7 @@ static void dfll_init_out_if(struct tegra_dfll *td)
         val = (td->lut_safe << DFLL_OUTPUT_CFG_SAFE_SHIFT) |
                 (td->lut_max << DFLL_OUTPUT_CFG_MAX_SHIFT) |
                 (td->lut_min << DFLL_OUTPUT_CFG_MIN_SHIFT);
-       dfll_writel(td, val, DFLL_OUTPUT_CFG);
+       dfll_i2c_writel(td, val, DFLL_OUTPUT_CFG);
-        dfll_wmb(td);
+        dfll_i2c_wmb(td);

         dfll_writel(td, 0, DFLL_OUTPUT_FORCE);

@@ -1146,7 +1146,8 @@ static int attr_registers_show(struct seq_file *s, 

void *data)
         seq_puts(s, "CONTROL REGISTERS:\n");
         for (offs = 0; offs <= DFLL_MONITOR_DATA; offs += 4)
                 seq_printf(s, "[0x%02x] = 0x%08x\n", offs,
-                          dfll_readl(td, offs));
+                               offs == DFLL_OUTPUT_CFG ? 
dfll_i2c_readl(td, offs) :
+                                       dfll_readl(td, offs));

         seq_puts(s, "\nI2C and INTR REGISTERS:\n");
         for (offs = DFLL_I2C_CFG; offs <= DFLL_I2C_STS; offs += 4)



Thanks,
Vince