Re: [PATCH V2 06/21] clk: tegra: dfll: CVB calculation alignment with the regulator

Jon Hunter
2018-12-13T11:18:20Z

On 13/12/2018 09:34, Joseph Lo wrote:
> The CVB table contains calibration data for the CPU DFLL based on
> process characterization. The regulator step and offset parameters depend
> on the regulator supplying vdd-cpu, not on the specific Tegra SKU.
>
> When using a PWM controlled regulator, the voltage step and offset are
> determined by the regulator type in use. This is specified in DT. When
> using an I2C controlled regulator, we can retrieve them from CPU regulator
> Then pass this information to the CVB table calculation function.
>
> Based on the work done of "Peter De Schrijver <pdeschrijver@nvidia.com>"
> and "Alex Frid <afrid@nvidia.com>".
>
> Signed-off-by: Joseph Lo <josephl@nvidia.com>
> ---
> *V2:
> - use the updated DT binding string for parsing
> - update the mechanism for geting regulator data from DT (PWM mode) or
> regulator (I2C mode)
> ---
> drivers/clk/tegra/clk-dfll.h | 6 ++-
> drivers/clk/tegra/clk-tegra124-dfll-fcpu.c | 57 ++++++++++++++++++++--
> drivers/clk/tegra/cvb.c | 12 +++--
> drivers/clk/tegra/cvb.h | 6 +--
> 4 files changed, 67 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/clk/tegra/clk-dfll.h b/drivers/clk/tegra/clk-dfll.h
> index 83352c8078f2..ecc43cb9b6f1 100644
> --- a/drivers/clk/tegra/clk-dfll.h
> +++ b/drivers/clk/tegra/clk-dfll.h
> @@ -1,6 +1,6 @@
> /*
> * clk-dfll.h - prototypes and macros for the Tegra DFLL clocksource driver
> - * Copyright (C) 2013 NVIDIA Corporation. All rights reserved.
> + * Copyright (C) 2013-2018 NVIDIA Corporation. All rights reserved.
> *
> * Aleksandr Frid <afrid@nvidia.com>
> * Paul Walmsley <pwalmsley@nvidia.com>
> @@ -22,11 +22,14 @@
> #include <linux/reset.h>
> #include <linux/types.h>
>
> +#include "cvb.h"
> +
> /**
> * struct tegra_dfll_soc_data - SoC-specific hooks/integration for the DFLL driver
> * @dev: struct device * that holds the OPP table for the DFLL
> * @max_freq: maximum frequency supported on this SoC
> * @cvb: CPU frequency table for this SoC
> + * @alignment: parameters of the regulator step and offset
> * @init_clock_trimmers: callback to initialize clock trimmers
> * @set_clock_trimmers_high: callback to tune clock trimmers for high voltage
> * @set_clock_trimmers_low: callback to tune clock trimmers for low voltage
> @@ -35,6 +38,7 @@ struct tegra_dfll_soc_data {
> struct device *dev;
> unsigned long max_freq;
> const struct cvb_table *cvb;
> + struct rail_alignment alignment;
>
> void (*init_clock_trimmers)(void);
> void (*set_clock_trimmers_high)(void);
> diff --git a/drivers/clk/tegra/clk-tegra124-dfll-fcpu.c b/drivers/clk/tegra/clk-tegra124-dfll-fcpu.c
> index 1a2cc113e5c8..189b5e20ee4e 100644
> --- a/drivers/clk/tegra/clk-tegra124-dfll-fcpu.c
> +++ b/drivers/clk/tegra/clk-tegra124-dfll-fcpu.c
> @@ -23,6 +23,7 @@
> #include <linux/init.h>
> #include <linux/of_device.h>
> #include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> #include <soc/tegra/fuse.h>
>
> #include "clk.h"
> @@ -50,9 +51,6 @@ static const struct cvb_table tegra124_cpu_cvb_tables[] = {
> .process_id = -1,
> .min_millivolts = 900,
> .max_millivolts = 1260,
> - .alignment = {
> - .step_uv = 10000, /* 10mV */
> - },
> .speedo_scale = 100,
> .voltage_scale = 1000,
> .entries = {
> @@ -105,11 +103,45 @@ static const struct of_device_id tegra124_dfll_fcpu_of_match[] = {
> { },
> };
>
> +static void get_alignment_from_dt(struct device *dev,
> + struct rail_alignment *align)
> +{
> + align->step_uv = 0;
> + align->offset_uv = 0;
> +
> + if (of_property_read_u32(dev->of_node,
> + "nvidia,pwm-voltage-step-microvolts",
> + &align->step_uv))
> + align->step_uv = 0;

Not sure why it is necessary to initialise this again on failure.

> +
> + if (of_property_read_u32(dev->of_node,
> + "nvidia,pwm-min-microvolts",
> + &align->offset_uv))
> + align->offset_uv = 0;

Same here.

> +}
> +
> +static int get_alignment_from_regulator(struct device *dev,
> + struct rail_alignment *align)
> +{
> + struct regulator *reg = devm_regulator_get(dev, "vdd-cpu");
> +
> + if (IS_ERR(reg))
> + return PTR_ERR(reg);
> +
> + align->offset_uv = regulator_list_voltage(reg, 0);
> + align->step_uv = regulator_get_linear_step(reg);
> +
> + devm_regulator_put(reg);
> +
> + return 0;
> +}
> +
> static int tegra124_dfll_fcpu_probe(struct platform_device *pdev)
> {
> int process_id, speedo_id, speedo_value, err;
> struct tegra_dfll_soc_data *soc;
> const struct dfll_fcpu_data *fcpu_data;
> + struct rail_alignment align;
>
> fcpu_data = of_device_get_match_data(&pdev->dev);
> if (!fcpu_data)
> @@ -135,12 +167,27 @@ static int tegra124_dfll_fcpu_probe(struct platform_device *pdev)
> return -ENODEV;
> }
>
> + if (of_property_read_bool(pdev->dev.of_node, "nvidia,pwm-to-pmic")) {
> + get_alignment_from_dt(&pdev->dev, &align);
> + } else {
> + err = get_alignment_from_regulator(&pdev->dev, &align);
> + if (err == -EPROBE_DEFER)
> + return -EPROBE_DEFER;

Why not return any error here? The print below maybe misleading.

> + }
> +
> + if (!align.step_uv) {
> + dev_err(&pdev->dev, "missing step uv\n");
> + return -EINVAL;
> + }
> +

Cheers
Jon

--
nvpublic