Re: [PATCH v7 03/16] clk: tegra: Add closed loop support for the DFLL

Peter De Schrijver
2015-02-12T14:12:12Z

On Thu, Jan 08, 2015 at 03:22:06PM +0200, Mikko Perttunen wrote:
> From: Tuomas Tynkkynen <ttynkkynen@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 <ttynkkynen@nvidia.com>
> Signed-off-by: Mikko Perttunen <mikko.perttunen@kapsi.fi>
Acked-By: pdeschrijver@nvidia.com
> ---
> drivers/clk/tegra/clk-dfll.c | 666 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 663 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/tegra/clk-dfll.c b/drivers/clk/tegra/clk-dfll.c
> index 6f46943..018489b 100644
> --- a/drivers/clk/tegra/clk-dfll.c
> +++ b/drivers/clk/tegra/clk-dfll.c
> @@ -205,12 +205,16 @@
> */
> #define REF_CLOCK_RATE 51000000UL
>
> +#define DVCO_RATE_TO_MULT(rate, ref_rate) ((rate) / ((ref_rate) / 2))
> +#define MULT_TO_DVCO_RATE(mult, ref_rate) ((mult) * ((ref_rate) / 2))
>
> /**
> * enum dfll_ctrl_mode - DFLL hardware operating mode
> * @DFLL_UNINITIALIZED: (uninitialized state - not in hardware bitfield)
> * @DFLL_DISABLED: DFLL not generating an output clock
> * @DFLL_OPEN_LOOP: DVCO running, but DFLL not adjusting voltage
> + * @DFLL_CLOSED_LOOP: DVCO running, and DFLL adjusting voltage to match
> + * the requested rate
> *
> * The integer corresponding to the last two states, minus one, is
> * written to the DFLL hardware to change operating modes.
> @@ -219,6 +223,7 @@ enum dfll_ctrl_mode {
> DFLL_UNINITIALIZED = 0,
> DFLL_DISABLED = 1,
> DFLL_OPEN_LOOP = 2,
> + DFLL_CLOSED_LOOP = 3,
> };
>
> /**
> @@ -236,6 +241,22 @@ enum dfll_tune_range {
> DFLL_TUNE_LOW = 1,
> };
>
> +/**
> + * struct dfll_rate_req - target DFLL rate request data
> + * @rate: target frequency, after the postscaling
> + * @dvco_target_rate: target frequency, after the postscaling
> + * @lut_index: LUT index at which voltage the dvco_target_rate will be reached
> + * @mult_bits: value to program to the MULT bits of the DFLL_FREQ_REQ register
> + * @scale_bits: value to program to the SCALE bits of the DFLL_FREQ_REQ register
> + */
> +struct dfll_rate_req {
> + unsigned long rate;
> + unsigned long dvco_target_rate;
> + int lut_index;
> + u8 mult_bits;
> + u8 scale_bits;
> +};
> +
> struct tegra_dfll {
> struct device *dev;
> struct tegra_dfll_soc_data *soc;
> @@ -259,9 +280,27 @@ struct tegra_dfll {
> struct dentry *debugfs_dir;
> struct clk_hw dfll_clk_hw;
> const char *output_clock_name;
> + struct dfll_rate_req last_req;
> + unsigned long last_unrounded_rate;
>
> /* Parameters from DT */
> u32 droop_ctrl;
> + u32 sample_rate;
> + u32 force_mode;
> + u32 cf;
> + u32 ci;
> + u32 cg;
> + bool cg_scale;
> +
> + /* I2C interface parameters */
> + u32 i2c_fs_rate;
> + u32 i2c_reg;
> + 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;
> };
>
> #define clk_hw_to_dfll(_hw) container_of(_hw, struct tegra_dfll, dfll_clk_hw)
> @@ -271,6 +310,7 @@ static const char * const mode_name[] = {
> [DFLL_UNINITIALIZED] = "uninitialized",
> [DFLL_DISABLED] = "disabled",
> [DFLL_OPEN_LOOP] = "open_loop",
> + [DFLL_CLOSED_LOOP] = "closed_loop",
> };
>
> /*
> @@ -497,6 +537,283 @@ static void dfll_set_mode(struct tegra_dfll *td,
> }
>
> /*
> + * DFLL-to-I2C controller interface
> + */
> +
> +/**
> + * dfll_i2c_set_output_enabled - enable/disable I2C PMIC voltage requests
> + * @td: DFLL instance
> + * @enable: whether to enable or disable the I2C voltage requests
> + *
> + * Set the master enable control for I2C control value updates. If disabled,
> + * then I2C control messages are inhibited, regardless of the DFLL mode.
> + */
> +static int dfll_i2c_set_output_enabled(struct tegra_dfll *td, bool enable)
> +{
> + u32 val;
> +
> + val = dfll_i2c_readl(td, DFLL_OUTPUT_CFG);
> +
> + if (enable)
> + val |= DFLL_OUTPUT_CFG_I2C_ENABLE;
> + else
> + val &= ~DFLL_OUTPUT_CFG_I2C_ENABLE;
> +
> + dfll_i2c_writel(td, val, DFLL_OUTPUT_CFG);
> + dfll_i2c_wmb(td);
> +
> + return 0;
> +}
> +
> +/**
> + * dfll_load_lut - load the voltage lookup table
> + * @td: struct tegra_dfll *
> + *
> + * Load the voltage-to-PMIC register value lookup table into the DFLL
> + * IP block memory. Look-up tables can be loaded at any time.
> + */
> +static void dfll_load_i2c_lut(struct tegra_dfll *td)
> +{
> + int i, lut_index;
> + 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;
> + else
> + lut_index = i;
> +
> + val = regulator_list_hardware_vsel(td->vdd_reg,
> + td->i2c_lut[lut_index]);
> + __raw_writel(val, td->lut_base + i * 4);
> + }
> +
> + dfll_i2c_wmb(td);
> +}
> +
> +/**
> + * dfll_init_i2c_if - set up the DFLL's DFLL-I2C interface
> + * @td: DFLL instance
> + *
> + * During DFLL driver initialization, program the DFLL-I2C interface
> + * with the PMU slave address, vdd register offset, and transfer mode.
> + * This data is used by the DFLL to automatically construct I2C
> + * voltage-set commands, which are then passed to the DFLL's internal
> + * I2C controller.
> + */
> +static void dfll_init_i2c_if(struct tegra_dfll *td)
> +{
> + u32 val;
> +
> + if (td->i2c_slave_addr > 0x7f) {
> + val = td->i2c_slave_addr << DFLL_I2C_CFG_SLAVE_ADDR_SHIFT_10BIT;
> + val |= DFLL_I2C_CFG_SLAVE_ADDR_10;
> + } else {
> + val = td->i2c_slave_addr << DFLL_I2C_CFG_SLAVE_ADDR_SHIFT_7BIT;
> + }
> + val |= DFLL_I2C_CFG_SIZE_MASK;
> + val |= DFLL_I2C_CFG_ARB_ENABLE;
> + dfll_i2c_writel(td, val, DFLL_I2C_CFG);
> +
> + dfll_i2c_writel(td, td->i2c_reg, DFLL_I2C_VDD_REG_ADDR);
> +
> + val = DIV_ROUND_UP(td->i2c_clk_rate, td->i2c_fs_rate * 8);
> + BUG_ON(!val || (val > DFLL_I2C_CLK_DIVISOR_MASK));
> + val = (val - 1) << DFLL_I2C_CLK_DIVISOR_FS_SHIFT;
> +
> + /* default hs divisor just in case */
> + val |= 1 << DFLL_I2C_CLK_DIVISOR_HS_SHIFT;
> + __raw_writel(val, td->i2c_controller_base + DFLL_I2C_CLK_DIVISOR);
> + dfll_i2c_wmb(td);
> +}
> +
> +/**
> + * 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_i2c_writel(td, val, DFLL_OUTPUT_CFG);
> + dfll_i2c_wmb(td);
> +
> + dfll_writel(td, 0, DFLL_OUTPUT_FORCE);
> + dfll_i2c_writel(td, 0, DFLL_INTR_EN);
> + dfll_i2c_writel(td, DFLL_INTR_MAX_MASK | DFLL_INTR_MIN_MASK,
> + DFLL_INTR_STS);
> +
> + dfll_load_i2c_lut(td);
> + dfll_init_i2c_if(td);
> +}
> +
> +/*
> + * Set/get the DFLL's targeted output clock rate
> + */
> +
> +/**
> + * find_lut_index_for_rate - determine I2C 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
> + * 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.
> + */
> +static int find_lut_index_for_rate(struct tegra_dfll *td, unsigned long rate)
> +{
> + struct dev_pm_opp *opp;
> + int i, uv;
> +
> + opp = dev_pm_opp_find_freq_ceil(td->soc->opp_dev, &rate);
> + if (IS_ERR(opp))
> + return PTR_ERR(opp);
> + uv = dev_pm_opp_get_voltage(opp);
> +
> + for (i = 0; i < td->i2c_lut_size; i++) {
> + if (regulator_list_voltage(td->vdd_reg, td->i2c_lut[i]) == uv)
> + return i;
> + }
> +
> + return -ENOENT;
> +}
> +
> +/**
> + * dfll_calculate_rate_request - calculate DFLL parameters for a given rate
> + * @td: DFLL instance
> + * @req: DFLL-rate-request structure
> + * @rate: the desired DFLL rate
> + *
> + * Populate the DFLL-rate-request record @req fields with the scale_bits
> + * and mult_bits fields, based on the target input rate. Returns 0 upon
> + * success, or -EINVAL if the requested rate in req->rate is too high
> + * or low for the DFLL to generate.
> + */
> +static int dfll_calculate_rate_request(struct tegra_dfll *td,
> + struct dfll_rate_req *req,
> + unsigned long rate)
> +{
> + u32 val;
> +
> + /*
> + * If requested rate is below the minimum DVCO rate, active the scaler.
> + * In the future the DVCO minimum voltage should be selected based on
> + * chip temperature and the actual minimum rate should be calibrated
> + * at runtime.
> + */
> + req->scale_bits = DFLL_FREQ_REQ_SCALE_MAX - 1;
> + if (rate < td->dvco_rate_min) {
> + int scale;
> +
> + scale = DIV_ROUND_CLOSEST(rate / 1000 * DFLL_FREQ_REQ_SCALE_MAX,
> + td->dvco_rate_min / 1000);
> + if (!scale) {
> + dev_err(td->dev, "%s: Rate %lu is too low\n",
> + __func__, rate);
> + return -EINVAL;
> + }
> + req->scale_bits = scale - 1;
> + rate = td->dvco_rate_min;
> + }
> +
> + /* Convert requested rate into frequency request and scale settings */
> + val = DVCO_RATE_TO_MULT(rate, td->ref_rate);
> + if (val > FREQ_MAX) {
> + dev_err(td->dev, "%s: Rate %lu is above dfll range\n",
> + __func__, rate);
> + return -EINVAL;
> + }
> + req->mult_bits = val;
> + req->dvco_target_rate = MULT_TO_DVCO_RATE(req->mult_bits, td->ref_rate);
> + req->rate = dfll_scale_dvco_rate(req->scale_bits,
> + req->dvco_target_rate);
> + req->lut_index = find_lut_index_for_rate(td, req->dvco_target_rate);
> + if (req->lut_index < 0)
> + return req->lut_index;
> +
> + return 0;
> +}
> +
> +/**
> + * dfll_set_frequency_request - start the frequency change operation
> + * @td: DFLL instance
> + * @req: rate request structure
> + *
> + * Tell the DFLL to try to change its output frequency to the
> + * frequency represented by @req. DFLL must be in closed-loop mode.
> + */
> +static void dfll_set_frequency_request(struct tegra_dfll *td,
> + struct dfll_rate_req *req)
> +{
> + u32 val = 0;
> + int force_val;
> + int coef = 128; /* FIXME: td->cg_scale? */;
> +
> + force_val = (req->lut_index - td->lut_safe) * coef / td->cg;
> + force_val = clamp(force_val, FORCE_MIN, FORCE_MAX);
> +
> + val |= req->mult_bits << DFLL_FREQ_REQ_MULT_SHIFT;
> + val |= req->scale_bits << DFLL_FREQ_REQ_SCALE_SHIFT;
> + val |= ((u32)force_val << DFLL_FREQ_REQ_FORCE_SHIFT) &
> + DFLL_FREQ_REQ_FORCE_MASK;
> + val |= DFLL_FREQ_REQ_FREQ_VALID | DFLL_FREQ_REQ_FORCE_ENABLE;
> +
> + dfll_writel(td, val, DFLL_FREQ_REQ);
> + dfll_wmb(td);
> +}
> +
> +/**
> + * tegra_dfll_request_rate - set the next rate for the DFLL to tune to
> + * @td: DFLL instance
> + * @rate: clock rate to target
> + *
> + * Convert the requested clock rate @rate into the DFLL control logic
> + * settings. In closed-loop mode, update new settings immediately to
> + * adjust DFLL output rate accordingly. Otherwise, just save them
> + * until the next switch to closed loop. Returns 0 upon success,
> + * -EPERM if the DFLL driver has not yet been initialized, or -EINVAL
> + * if @rate is outside the DFLL's tunable range.
> + */
> +static int dfll_request_rate(struct tegra_dfll *td, unsigned long rate)
> +{
> + int ret;
> + struct dfll_rate_req req;
> +
> + if (td->mode == DFLL_UNINITIALIZED) {
> + dev_err(td->dev, "%s: Cannot set DFLL rate in %s mode\n",
> + __func__, mode_name[td->mode]);
> + return -EPERM;
> + }
> +
> + ret = dfll_calculate_rate_request(td, &req, rate);
> + if (ret)
> + return ret;
> +
> + td->last_unrounded_rate = rate;
> + td->last_req = req;
> +
> + if (td->mode == DFLL_CLOSED_LOOP)
> + dfll_set_frequency_request(td, &td->last_req);
> +
> + return 0;
> +}
> +
> +/*
> * DFLL enable/disable & open-loop <-> closed-loop transitions
> */
>
> @@ -568,8 +885,76 @@ static void dfll_set_open_loop_config(struct tegra_dfll *td)
> dfll_wmb(td);
> }
>
> +/**
> + * tegra_dfll_lock - switch from open-loop to closed-loop mode
> + * @td: DFLL instance
> + *
> + * Switch from OPEN_LOOP state to CLOSED_LOOP state. Returns 0 upon success,
> + * -EINVAL if the DFLL's target rate hasn't been set yet, or -EPERM if the
> + * DFLL is not currently in open-loop mode.
> + */
> +static int dfll_lock(struct tegra_dfll *td)
> +{
> + struct dfll_rate_req *req = &td->last_req;
> +
> + switch (td->mode) {
> + case DFLL_CLOSED_LOOP:
> + return 0;
> +
> + case DFLL_OPEN_LOOP:
> + if (req->rate == 0) {
> + dev_err(td->dev, "%s: Cannot lock DFLL at rate 0\n",
> + __func__);
> + return -EINVAL;
> + }
> +
> + dfll_i2c_set_output_enabled(td, true);
> + dfll_set_mode(td, DFLL_CLOSED_LOOP);
> + dfll_set_frequency_request(td, req);
> + return 0;
> +
> + default:
> + BUG_ON(td->mode > DFLL_CLOSED_LOOP);
> + dev_err(td->dev, "%s: Cannot lock DFLL in %s mode\n",
> + __func__, mode_name[td->mode]);
> + return -EPERM;
> + }
> +}
> +
> +/**
> + * tegra_dfll_unlock - switch from closed-loop to open-loop mode
> + * @td: DFLL instance
> + *
> + * Switch from CLOSED_LOOP state to OPEN_LOOP state. Returns 0 upon success,
> + * or -EPERM if the DFLL is not currently in open-loop mode.
> + */
> +static int dfll_unlock(struct tegra_dfll *td)
> +{
> + switch (td->mode) {
> + case DFLL_CLOSED_LOOP:
> + dfll_set_open_loop_config(td);
> + dfll_set_mode(td, DFLL_OPEN_LOOP);
> + dfll_i2c_set_output_enabled(td, false);
> + return 0;
> +
> + case DFLL_OPEN_LOOP:
> + return 0;
> +
> + default:
> + BUG_ON(td->mode > DFLL_CLOSED_LOOP);
> + dev_err(td->dev, "%s: Cannot unlock DFLL in %s mode\n",
> + __func__, mode_name[td->mode]);
> + return -EPERM;
> + }
> +}
> +
> /*
> * Clock framework integration
> + *
> + * When the DFLL is being controlled by the CCF, always enter closed loop
> + * mode when the clk is enabled. This requires that a DFLL rate request
> + * has been set beforehand, which implies that a clk_set_rate() call is
> + * always required before a clk_enable().
> */
>
> static int dfll_clk_is_enabled(struct clk_hw *hw)
> @@ -582,21 +967,72 @@ static int dfll_clk_is_enabled(struct clk_hw *hw)
> static int dfll_clk_enable(struct clk_hw *hw)
> {
> struct tegra_dfll *td = clk_hw_to_dfll(hw);
> + int ret;
> +
> + ret = dfll_enable(td);
> + if (ret)
> + return ret;
> +
> + ret = dfll_lock(td);
> + if (ret)
> + dfll_disable(td);
>
> - return dfll_enable(td);
> + return ret;
> }
>
> static void dfll_clk_disable(struct clk_hw *hw)
> {
> struct tegra_dfll *td = clk_hw_to_dfll(hw);
> + int ret;
> +
> + ret = dfll_unlock(td);
> + if (!ret)
> + dfll_disable(td);
> +}
> +
> +static unsigned long dfll_clk_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct tegra_dfll *td = clk_hw_to_dfll(hw);
>
> - dfll_disable(td);
> + return td->last_unrounded_rate;
> +}
> +
> +static long dfll_clk_round_rate(struct clk_hw *hw,
> + unsigned long rate,
> + unsigned long *parent_rate)
> +{
> + struct tegra_dfll *td = clk_hw_to_dfll(hw);
> + struct dfll_rate_req req;
> + int ret;
> +
> + ret = dfll_calculate_rate_request(td, &req, rate);
> + if (ret)
> + return ret;
> +
> + /*
> + * Don't return the rounded rate, since it doesn't really matter as
> + * the output rate will be voltage controlled anyway, and cpufreq
> + * freaks out if any rounding happens.
> + */
> + return rate;
> +}
> +
> +static int dfll_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct tegra_dfll *td = clk_hw_to_dfll(hw);
> +
> + return dfll_request_rate(td, rate);
> }
>
> static const struct clk_ops dfll_clk_ops = {
> .is_enabled = dfll_clk_is_enabled,
> .enable = dfll_clk_enable,
> .disable = dfll_clk_disable,
> + .recalc_rate = dfll_clk_recalc_rate,
> + .round_rate = dfll_clk_round_rate,
> + .set_rate = dfll_clk_set_rate,
> };
>
> static struct clk_init_data dfll_clk_init_data = {
> @@ -675,6 +1111,23 @@ static int attr_enable_set(void *data, u64 val)
> DEFINE_SIMPLE_ATTRIBUTE(enable_fops, attr_enable_get, attr_enable_set,
> "%llu\n");
>
> +static int attr_lock_get(void *data, u64 *val)
> +{
> + struct tegra_dfll *td = data;
> +
> + *val = (td->mode == DFLL_CLOSED_LOOP);
> +
> + return 0;
> +}
> +static int attr_lock_set(void *data, u64 val)
> +{
> + struct tegra_dfll *td = data;
> +
> + return val ? dfll_lock(td) : dfll_unlock(td);
> +}
> +DEFINE_SIMPLE_ATTRIBUTE(lock_fops, attr_lock_get, attr_lock_set,
> + "%llu\n");
> +
> static int attr_rate_get(void *data, u64 *val)
> {
> struct tegra_dfll *td = data;
> @@ -683,7 +1136,14 @@ static int attr_rate_get(void *data, u64 *val)
>
> return 0;
> }
> -DEFINE_SIMPLE_ATTRIBUTE(rate_fops, attr_rate_get, NULL, "%llu\n");
> +
> +static int attr_rate_set(void *data, u64 val)
> +{
> + struct tegra_dfll *td = data;
> +
> + return dfll_request_rate(td, val);
> +}
> +DEFINE_SIMPLE_ATTRIBUTE(rate_fops, attr_rate_get, attr_rate_set, "%llu\n");
>
> static int attr_registers_show(struct seq_file *s, void *data)
> {
> @@ -749,6 +1209,10 @@ static int dfll_debug_init(struct tegra_dfll *td)
> td->debugfs_dir, td, &enable_fops))
> goto err_out;
>
> + if (!debugfs_create_file("lock", S_IRUGO,
> + td->debugfs_dir, td, &lock_fops))
> + goto err_out;
> +
> if (!debugfs_create_file("rate", S_IRUGO,
> td->debugfs_dir, td, &rate_fops))
> goto err_out;
> @@ -780,6 +1244,19 @@ err_out:
> */
> static void dfll_set_default_params(struct tegra_dfll *td)
> {
> + u32 val;
> +
> + val = DIV_ROUND_UP(td->ref_rate, td->sample_rate * 32);
> + BUG_ON(val > DFLL_CONFIG_DIV_MASK);
> + dfll_writel(td, val, DFLL_CONFIG);
> +
> + val = (td->force_mode << DFLL_PARAMS_FORCE_MODE_SHIFT) |
> + (td->cf << DFLL_PARAMS_CF_PARAM_SHIFT) |
> + (td->ci << DFLL_PARAMS_CI_PARAM_SHIFT) |
> + (td->cg << DFLL_PARAMS_CG_PARAM_SHIFT) |
> + (td->cg_scale ? DFLL_PARAMS_CG_SCALE : 0);
> + dfll_writel(td, val, DFLL_PARAMS);
> +
> dfll_tune_low(td);
> dfll_writel(td, td->droop_ctrl, DFLL_DROOP_CTRL);
> dfll_writel(td, DFLL_MONITOR_CTRL_FREQ, DFLL_MONITOR_CTRL);
> @@ -858,6 +1335,8 @@ static int dfll_init(struct tegra_dfll *td)
> goto di_err2;
> }
>
> + td->last_unrounded_rate = 0;
> +
> pm_runtime_enable(td->dev);
> pm_runtime_get_sync(td->dev);
>
> @@ -869,6 +1348,8 @@ static int dfll_init(struct tegra_dfll *td)
>
> dfll_set_open_loop_config(td);
>
> + dfll_init_out_if(td);
> +
> pm_runtime_put_sync(td->dev);
>
> return 0;
> @@ -888,6 +1369,130 @@ di_err1:
> * DT data fetch
> */
>
> +/*
> + * Find a PMIC voltage register-to-voltage mapping for the given voltage.
> + * An exact voltage match is required.
> + */
> +static int find_vdd_map_entry_exact(struct tegra_dfll *td, int uV)
> +{
> + int i, n_voltages, reg_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)
> + break;
> +
> + if (uV == reg_uV)
> + return i;
> + }
> +
> + dev_err(td->dev, "no voltage map entry for %d uV\n", uV);
> + return -EINVAL;
> +}
> +
> +/*
> + * Find a PMIC voltage register-to-voltage mapping for the given voltage,
> + * rounding up to the closest supported voltage.
> + * */
> +static int find_vdd_map_entry_min(struct tegra_dfll *td, int uV)
> +{
> + int i, n_voltages, reg_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)
> + break;
> +
> + if (uV <= reg_uV)
> + return i;
> + }
> +
> + dev_err(td->dev, "no voltage map entry rounding to %d uV\n", uV);
> + return -EINVAL;
> +}
> +
> +/**
> + * dfll_build_i2c_lut - build the I2C voltage register lookup table
> + * @td: DFLL instance
> + *
> + * The DFLL hardware has 33 bytes of look-up table RAM that must be filled with
> + * PMIC voltage register values that span the entire DFLL operating range.
> + * This function builds the look-up table based on the OPP table provided by
> + * the soc-specific platform driver (td->soc->opp_dev) and the PMIC
> + * register-to-voltage mapping queried from the regulator framework.
> + *
> + * On success, fills in td->i2c_lut and returns 0, or -err on failure.
> + */
> +static int dfll_build_i2c_lut(struct tegra_dfll *td)
> +{
> + int ret = -EINVAL;
> + int j, v, v_max, v_opp;
> + int selector;
> + unsigned long rate;
> + struct dev_pm_opp *opp;
> +
> + rcu_read_lock();
> +
> + rate = ULONG_MAX;
> + opp = dev_pm_opp_find_freq_floor(td->soc->opp_dev, &rate);
> + if (IS_ERR(opp)) {
> + dev_err(td->dev, "couldn't get vmax opp, empty opp table?\n");
> + goto out;
> + }
> + v_max = dev_pm_opp_get_voltage(opp);
> +
> + v = td->soc->min_millivolts * 1000;
> + td->i2c_lut[0] = find_vdd_map_entry_exact(td, v);
> + if (td->i2c_lut[0] < 0)
> + goto out;
> +
> + for (j = 1, rate = 0; ; rate++) {
> + opp = dev_pm_opp_find_freq_ceil(td->soc->opp_dev, &rate);
> + if (IS_ERR(opp))
> + break;
> + v_opp = dev_pm_opp_get_voltage(opp);
> +
> + if (v_opp <= td->soc->min_millivolts * 1000)
> + td->dvco_rate_min = dev_pm_opp_get_freq(opp);
> +
> + for (;;) {
> + v += max(1, (v_max - v) / (MAX_DFLL_VOLTAGES - j));
> + if (v >= v_opp)
> + break;
> +
> + selector = find_vdd_map_entry_min(td, v);
> + if (selector < 0)
> + goto out;
> + if (selector != td->i2c_lut[j - 1])
> + td->i2c_lut[j++] = selector;
> + }
> +
> + v = (j == MAX_DFLL_VOLTAGES - 1) ? v_max : v_opp;
> + selector = find_vdd_map_entry_exact(td, v);
> + if (selector < 0)
> + goto out;
> + if (selector != td->i2c_lut[j - 1])
> + td->i2c_lut[j++] = selector;
> +
> + if (v >= v_max)
> + break;
> + }
> + td->i2c_lut_size = j;
> +
> + if (!td->dvco_rate_min)
> + dev_err(td->dev, "no opp above DFLL minimum voltage %d mV\n",
> + td->soc->min_millivolts);
> + else
> + ret = 0;
> +
> +out:
> + rcu_read_unlock();
> +
> + return ret;
> +}
> +
> /**
> * read_dt_param - helper function for reading required parameters from the DT
> * @td: DFLL instance
> @@ -912,6 +1517,50 @@ static bool read_dt_param(struct tegra_dfll *td, const char *param, u32 *dest)
> }
>
> /**
> + * 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;
> + }
> + td->i2c_reg = vsel_reg;
> +
> + ret = dfll_build_i2c_lut(td);
> + if (ret) {
> + dev_err(td->dev, "couldn't build I2C LUT\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +/**
> * dfll_fetch_common_params - read DFLL parameters from the device tree
> * @td: DFLL instance
> *
> @@ -923,6 +1572,13 @@ static int dfll_fetch_common_params(struct tegra_dfll *td)
> bool ok = true;
>
> ok &= read_dt_param(td, "nvidia,droop-ctrl", &td->droop_ctrl);
> + ok &= read_dt_param(td, "nvidia,sample-rate", &td->sample_rate);
> + ok &= read_dt_param(td, "nvidia,force-mode", &td->force_mode);
> + ok &= read_dt_param(td, "nvidia,cf", &td->cf);
> + ok &= read_dt_param(td, "nvidia,ci", &td->ci);
> + ok &= read_dt_param(td, "nvidia,cg", &td->cg);
> + td->cg_scale = of_property_read_bool(td->dev->of_node,
> + "nvidia,cg-scale");
>
> if (of_property_read_string(td->dev->of_node, "clock-output-names",
> &td->output_clock_name)) {
> @@ -978,6 +1634,10 @@ int tegra_dfll_register(struct platform_device *pdev,
> return ret;
> }
>
> + ret = dfll_fetch_i2c_params(td);
> + if (ret)
> + return ret;
> +
> mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> if (!mem) {
> dev_err(td->dev, "no control register resource\n");
> --
> 2.2.1
>