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Subject[PATCH v3 05/11] clk: tegra: prepare dfll driver for PWM regulator
Date
This patch prepares the dfll driver to work with PWM regulators.
To do this we introduce a new array lut_uv which gives the voltage for
a given index generated by the dfll logic. This index will then be
translated to a PMIC voltage ID in case of I2C using the i2c_lut. In case
of a PWM regulator, it will be used to determine the PWM duty cycle.
We also introduce lut_bottom which holds the lowest voltage we will ever
need. In case of I2C this can be set to zero because the i2c_lut will be
initialized such that entry 0 will be the lowest voltage we will ever
need. In case of PWM, the lowest voltage is determined by the regulator
hardware so we need this software limit. Note that this is different
from lut_min which gives the lowest voltage we allow taking temperature
into account. In a future patchset we will update lut_vmin dynamically.
Similarly lut_max will be the highest voltage allowed taking temperature
into accouint. Also this will be updated dynamically once temperature
dependence will be introduced.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
---
drivers/clk/tegra/clk-dfll.c | 62 ++++++++++++++++++++++++++------------------
1 file changed, 37 insertions(+), 25 deletions(-)

diff --git a/drivers/clk/tegra/clk-dfll.c b/drivers/clk/tegra/clk-dfll.c
index 0a7deee..fa97763 100644
--- a/drivers/clk/tegra/clk-dfll.c
+++ b/drivers/clk/tegra/clk-dfll.c
@@ -301,9 +301,10 @@ struct tegra_dfll {
u32 i2c_slave_addr;

/* i2c_lut array entries are regulator framework selectors */
- unsigned i2c_lut[MAX_DFLL_VOLTAGES];
- int i2c_lut_size;
- u8 lut_min, lut_max, lut_safe;
+ unsigned int i2c_lut[MAX_DFLL_VOLTAGES];
+ unsigned int lut_uv[MAX_DFLL_VOLTAGES];
+ int lut_size;
+ u8 lut_bottom, lut_min, lut_max, lut_safe;
};

#define clk_hw_to_dfll(_hw) container_of(_hw, struct tegra_dfll, dfll_clk_hw)
@@ -531,10 +532,10 @@ static void dfll_load_i2c_lut(struct tegra_dfll *td)
u32 val;

for (i = 0; i < MAX_DFLL_VOLTAGES; i++) {
- if (i < td->lut_min)
- lut_index = td->lut_min;
- else if (i > td->lut_max)
- lut_index = td->lut_max;
+ if (i < td->lut_bottom)
+ lut_index = td->lut_bottom;
+ else if (i > td->lut_size - 1)
+ lut_index = td->lut_size - 1;
else
lut_index = i;

@@ -594,9 +595,9 @@ 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;
+ td->lut_min = td->lut_bottom;
+ td->lut_max = td->lut_size - 1;
+ td->lut_safe = td->lut_min + (td->lut_min < td->lut_max ? 1 : 0);

dfll_i2c_writel(td, 0, DFLL_OUTPUT_CFG);
val = (td->lut_safe << DFLL_OUTPUT_CFG_SAFE_SHIFT) |
@@ -619,11 +620,11 @@ static void dfll_init_out_if(struct tegra_dfll *td)
*/

/**
- * find_lut_index_for_rate - determine I2C LUT index for given DFLL rate
+ * find_lut_index_for_rate - determine LUT index for given DFLL rate
* @td: DFLL instance
* @rate: clock rate
*
- * Determines the index of a I2C LUT entry for a voltage that approximately
+ * Determines the index of a LUT entry for a voltage that approximately
* produces the given DFLL clock rate. This is used when forcing a value
* to the integrator during rate changes. Returns -ENOENT if a suitable
* LUT index is not found.
@@ -637,11 +638,11 @@ static int find_lut_index_for_rate(struct tegra_dfll *td, unsigned long rate)
if (IS_ERR(opp))
return PTR_ERR(opp);

- uv = dev_pm_opp_get_voltage(opp);
+ uv = dev_pm_opp_get_voltage(opp) / td->soc->alignment.step_uv;
dev_pm_opp_put(opp);

- for (i = 0; i < td->i2c_lut_size; i++) {
- if (regulator_list_voltage(td->vdd_reg, td->i2c_lut[i]) == uv)
+ for (i = td->lut_bottom; i < td->lut_size; i++) {
+ if ((td->lut_uv[i] / td->soc->alignment.step_uv) >= uv)
return i;
}

@@ -1377,15 +1378,17 @@ static int dfll_init(struct tegra_dfll *td)
*/
static int find_vdd_map_entry_exact(struct tegra_dfll *td, int uV)
{
- int i, n_voltages, reg_uV;
+ int i, n_voltages, reg_mult, align_mult;

+ align_mult = uV / td->soc->alignment.step_uv;
n_voltages = regulator_count_voltages(td->vdd_reg);
for (i = 0; i < n_voltages; i++) {
- reg_uV = regulator_list_voltage(td->vdd_reg, i);
- if (reg_uV < 0)
+ reg_mult = regulator_list_voltage(td->vdd_reg, i) /
+ td->soc->alignment.step_uv;
+ if (reg_mult < 0)
break;

- if (uV == reg_uV)
+ if (align_mult == reg_mult)
return i;
}

@@ -1399,15 +1402,17 @@ static int find_vdd_map_entry_exact(struct tegra_dfll *td, int uV)
* */
static int find_vdd_map_entry_min(struct tegra_dfll *td, int uV)
{
- int i, n_voltages, reg_uV;
+ int i, n_voltages, reg_mult, align_mult;

+ align_mult = uV / td->soc->alignment.step_uv;
n_voltages = regulator_count_voltages(td->vdd_reg);
for (i = 0; i < n_voltages; i++) {
- reg_uV = regulator_list_voltage(td->vdd_reg, i);
- if (reg_uV < 0)
+ reg_mult = regulator_list_voltage(td->vdd_reg, i) /
+ td->soc->alignment.step_uv;
+ if (reg_mult < 0)
break;

- if (uV <= reg_uV)
+ if (align_mult <= reg_mult)
return i;
}

@@ -1450,8 +1455,10 @@ static int dfll_build_i2c_lut(struct tegra_dfll *td)
if (lut < 0)
goto out;
td->i2c_lut[0] = lut;
+ td->lut_bottom = 0;

for (j = 1, rate = 0; ; rate++) {
+
opp = dev_pm_opp_find_freq_ceil(td->soc->dev, &rate);
if (IS_ERR(opp))
break;
@@ -1484,13 +1491,18 @@ static int dfll_build_i2c_lut(struct tegra_dfll *td)
if (v >= v_max)
break;
}
- td->i2c_lut_size = j;
+ td->lut_size = j;

if (!td->dvco_rate_min)
dev_err(td->dev, "no opp above DFLL minimum voltage %d mV\n",
td->soc->cvb->min_millivolts);
- else
+ else {
ret = 0;
+ for (j = 0; j < td->lut_size; j++)
+ td->lut_uv[j] =
+ regulator_list_voltage(td->vdd_reg,
+ td->i2c_lut[j]);
+ }

out:
return ret;
--
1.9.1
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