Hi,
On 08/19/2014 11:33 AM, Tuomas Tynkkynen wrote:
From: Tuomas Tynkkynen <ttynkky...@nvidia.com>
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 <ttynkky...@nvidia.com>
---
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_fetch_i2c_params - query PMIC I2C params from DT & regulator subsystem
+ * @td: DFLL instance
+ *
+ * Read all the parameters required for operation in I2C mode. The parameters
+ * can originate from the device tree or the regulator subsystem.
+ * Returns 0 on success or -err on failure.
+ */
+static int dfll_fetch_i2c_params(struct tegra_dfll *td)
+{
+ struct regmap *regmap;
+ struct device *i2c_dev;
+ struct i2c_client *i2c_client;
+ int vsel_reg, vsel_mask;
+ int ret;
+
+ if (!read_dt_param(td, "nvidia,i2c-fs-rate", &td->i2c_fs_rate))
+ return -EINVAL;
+
+ regmap = regulator_get_regmap(td->vdd_reg);
+ i2c_dev = regmap_get_device(regmap);
+ i2c_client = to_i2c_client(i2c_dev);
+
+ td->i2c_slave_addr = i2c_client->addr;
+
+ ret = regulator_get_hardware_vsel_register(td->vdd_reg,
+ &vsel_reg,
+ &vsel_mask);
+ if (ret < 0) {
+ dev_err(td->dev,
+ "regulator unsuitable for DFLL I2C operation\n");
+ return -EINVAL;
+ }
+
It seems that the td->i2c_reg never gets initialized, and we're lucky on
JetsonTK1 or Norrin. We should initialize the regulator offset here. Like:
td->i2c_reg = vsel_reg;
Thanks,
Vince
+ ret = dfll_build_i2c_lut(td);
+ if (ret) {
+ dev_err(td->dev, "couldn't build I2C LUT\n");
+ return ret;
+ }
+
+ return 0;
+}
+
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