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Date: Thu, 18 Nov 2021 19:27:19 +0530
From: "Satya Priya Kakitapalli (Temp)" <quic_c_skakit@...cinc.com>
To: Stephen Boyd <swboyd@...omium.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Rob Herring <robh+dt@...nel.org>
CC: Liam Girdwood <lgirdwood@...il.com>,
Mark Brown <broonie@...nel.org>, <subbaram@...eaurora.org>,
Das Srinagesh <gurus@...eaurora.org>,
<linux-arm-msm@...r.kernel.org>, Lee Jones <lee.jones@...aro.org>,
<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V3 3/4] regulator: Add a regulator driver for the PM8008
PMIC
On 10/29/2021 1:49 AM, Stephen Boyd wrote:
> Quoting Satya Priya (2021-10-28 08:14:31)
>> diff --git a/drivers/regulator/qcom-pm8008-regulator.c b/drivers/regulator/qcom-pm8008-regulator.c
>> new file mode 100644
>> index 0000000..74ba682
>> --- /dev/null
>> +++ b/drivers/regulator/qcom-pm8008-regulator.c
>> @@ -0,0 +1,269 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/* Copyright (c) 2021, The Linux Foundation. All rights reserved. */
>> +
>> +#include <linux/device.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +#include <linux/regulator/driver.h>
>> +#include <linux/regulator/machine.h>
>> +#include <linux/regulator/of_regulator.h>
>> +
>> +#define STARTUP_DELAY_USEC 20
>> +#define VSET_STEP_MV 8
>> +#define VSET_STEP_UV (VSET_STEP_MV * 1000)
>> +
>> +#define LDO_ENABLE_REG(base) (base + 0x46)
> Add parenthesis around base as well ((base) + 0x46)
Okay
>> +#define ENABLE_BIT BIT(7)
>> +
>> +#define LDO_STATUS1_REG(base) (base + 0x08)
>> +#define VREG_READY_BIT BIT(7)
>> +
>> +#define LDO_VSET_LB_REG(base) (base + 0x40)
>> +
>> +#define LDO_STEPPER_CTL_REG(base) (base + 0x3b)
>> +#define DEFAULT_VOLTAGE_STEPPER_RATE 38400
>> +#define STEP_RATE_MASK GENMASK(1, 0)
>> +
>> +struct regulator_data {
>> + const char *name;
>> + const char *supply_name;
>> + int min_uv;
>> + int max_uv;
>> + int min_dropout_uv;
>> +};
>> +
>> +struct pm8008_regulator {
>> + struct device *dev;
>> + struct regmap *regmap;
>> + struct regulator_desc rdesc;
>> + struct regulator_dev *rdev;
>> + struct device_node *of_node;
> This isn't used outside of probe so please drop it. Same goes for any
> other struct member that we don't need to keep around beyond probe. Drop
> them. rdev?
Okay, I'll remove.
>> + u16 base;
>> + int step_rate;
>> +};
>> +
>> +static const struct regulator_data reg_data[] = {
>> + /* name parent min_uv max_uv headroom_uv */
>> + { "l1", "vdd_l1_l2", 528000, 1504000, 225000 },
>> + { "l2", "vdd_l1_l2", 528000, 1504000, 225000 },
>> + { "l3", "vdd_l3_l4", 1504000, 3400000, 200000 },
>> + { "l4", "vdd_l3_l4", 1504000, 3400000, 200000 },
>> + { "l5", "vdd_l5", 1504000, 3400000, 300000 },
>> + { "l6", "vdd_l6", 1504000, 3400000, 300000 },
>> + { "l7", "vdd_l7", 1504000, 3400000, 300000 },
>> + { }
>> +};
>> +
>> +static int pm8008_regulator_get_voltage(struct regulator_dev *rdev)
>> +{
>> + struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
>> + __le16 mV;
>> + int rc;
>> +
>> + rc = regmap_bulk_read(pm8008_reg->regmap,
>> + LDO_VSET_LB_REG(pm8008_reg->base), (void *)&mV, 2);
>> + if (rc < 0) {
>> + dev_err(pm8008_reg->dev,
>> + "failed to read regulator voltage rc=%d\n", rc);
> Put it all on one line?
Okay.
>> + return rc;
>> + }
>> +
>> + return le16_to_cpu(mV) * 1000;
>> +}
>> +
>> +static inline int pm8008_write_voltage(struct pm8008_regulator *pm8008_reg,
>> + int min_uv, int max_uv)
>> +{
>> + int rc, mv;
>> + u16 vset_raw;
>> +
>> + mv = DIV_ROUND_UP(min_uv, 1000);
>> +
>> + /*
>> + * Each LSB of regulator is 1mV and the voltage setpoint
>> + * should be multiple of 8mV(step).
>> + */
>> + mv = DIV_ROUND_UP(mv, VSET_STEP_MV) * VSET_STEP_MV;
>> + if (mv * 1000 > max_uv) {
>> + dev_err(pm8008_reg->dev,
>> + "requested voltage (%d uV) above maximum limit (%d uV)\n",
>> + mv*1000, max_uv);
>> + return -EINVAL;
>> + }
>> +
>> + vset_raw = cpu_to_le16(mv);
>> +
>> + rc = regmap_bulk_write(pm8008_reg->regmap,
>> + LDO_VSET_LB_REG(pm8008_reg->base),
>> + (const void *)&vset_raw, sizeof(vset_raw));
>> + if (rc < 0) {
>> + dev_err(pm8008_reg->dev, "failed to write voltage rc=%d\n", rc);
> If this uses the regulator_dev::dev then we'll know which regulator is
> failing, instead of just that some regulator failed inside the PMIC.
OK, but in this API we do not have the rdev, in other APIs wherever
possible I'll use rdev->dev.
>> + return rc;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int pm8008_regulator_set_voltage_time(struct regulator_dev *rdev,
>> + int old_uV, int new_uv)
>> +{
>> + struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
>> +
>> + return DIV_ROUND_UP(abs(new_uv - old_uV), pm8008_reg->step_rate);
>> +}
>> +
>> +static int pm8008_regulator_set_voltage(struct regulator_dev *rdev,
>> + int min_uv, int max_uv, unsigned int *selector)
>> +{
>> + struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
>> + int rc;
>> +
>> + rc = pm8008_write_voltage(pm8008_reg, min_uv, max_uv);
>> + if (rc < 0)
>> + return rc;
>> +
>> + *selector = DIV_ROUND_UP(min_uv - pm8008_reg->rdesc.min_uV,
>> + VSET_STEP_UV);
>> +
>> + dev_dbg(pm8008_reg->dev, "voltage set to %d\n", min_uv);
>> + return 0;
>> +}
>> +
>> +static const struct regulator_ops pm8008_regulator_ops = {
>> + .enable = regulator_enable_regmap,
>> + .disable = regulator_disable_regmap,
>> + .is_enabled = regulator_is_enabled_regmap,
>> + .set_voltage = pm8008_regulator_set_voltage,
> Can we use set_voltage_sel instead?
Yes
>> + .get_voltage = pm8008_regulator_get_voltage,
>> + .list_voltage = regulator_list_voltage_linear,
>> + .set_voltage_time = pm8008_regulator_set_voltage_time,
>> +};
>> +
>> +static int pm8008_regulator_of_parse(struct device_node *node,
>> + const struct regulator_desc *desc,
>> + struct regulator_config *config)
>> +{
>> + struct pm8008_regulator *pm8008_reg = config->driver_data;
>> + struct device *dev = config->dev;
>> + int rc;
>> + u8 reg;
>> +
>> + rc = of_property_read_u32(node, "regulator-min-dropout-voltage-microvolt",
>> + &pm8008_reg->rdesc.min_dropout_uV);
>> + if (rc) {
>> + dev_err(dev, "failed to read min-dropout voltage rc=%d\n", rc);
>> + return rc;
>> + }
>> +
>> + /* get slew rate */
>> + rc = regmap_bulk_read(pm8008_reg->regmap,
>> + LDO_STEPPER_CTL_REG(pm8008_reg->base), (void *)®, 1);
> Just make reg unsigned int to avoid the cast.
Ok
>> + if (rc < 0) {
>> + dev_err(dev, "%s: failed to read step rate configuration rc=%d\n",
>> + pm8008_reg->rdesc.name, rc);
>> + return rc;
>> + }
> reg &= STEP_RATE_MASK;
> pm8008_reg->step_rate = DEFAULT_VOLTAGE_STEPPER_RATE >> reg;
Ok
>> + pm8008_reg->step_rate
>> + = DEFAULT_VOLTAGE_STEPPER_RATE >> (reg & STEP_RATE_MASK);
>> +
>> + return 0;
>> +}
>> +
>> +static int pm8008_regulator_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct device_node *node = pdev->dev.of_node;
>> + struct pm8008_regulator *pm8008_reg;
>> + struct regmap *regmap;
>> + struct regulator_config reg_config = {};
>> + const struct regulator_data *reg;
>> + struct regulator_init_data *init_data;
>> + int rc;
>> + u32 base;
>> +
>> + regmap = dev_get_regmap(dev->parent, NULL);
>> + if (!regmap) {
>> + dev_err(dev, "parent regmap is missing\n");
>> + return -EINVAL;
>> + }
>> +
>> + for (reg = ®_data[0]; reg->name; reg++) {
>> + pm8008_reg = devm_kzalloc(dev, sizeof(*pm8008_reg), GFP_KERNEL);
>> +
>> + pm8008_reg->regmap = regmap;
>> +
>> + pm8008_reg->of_node = of_get_child_by_name(node, reg->name);
> This of_node reference needs to be put somewhere.
>
>> + if (!pm8008_reg->of_node) {
>> + dev_err(dev, "child node %s not found\n", reg->name);
>> + return -ENODEV;
>> + }
>> +
>> + pm8008_reg->dev = dev;
>> +
>> + rc = of_property_read_u32(pm8008_reg->of_node, "reg", &base);
>> + if (rc < 0) {
>> + dev_err(dev, "%s: failed to get regulator base rc=%d\n",
>> + reg->name, rc);
>> + return rc;
>> + }
>> + pm8008_reg->base = base;
>> +
>> + init_data = of_get_regulator_init_data(dev, pm8008_reg->of_node,
>> + &pm8008_reg->rdesc);
> Is this necessary?
I guess its not necessary, I'll remove and validate once.
>> + if (!init_data) {
>> + dev_err(dev, "%s: failed to get regulator data\n", reg->name);
>> + return -ENODATA;
>> + }
>> +
>> + pm8008_reg->rdesc.type = REGULATOR_VOLTAGE;
>> + pm8008_reg->rdesc.ops = &pm8008_regulator_ops;
>> + pm8008_reg->rdesc.name = init_data->constraints.name;
>> + pm8008_reg->rdesc.supply_name = reg->supply_name;
>> + pm8008_reg->rdesc.of_match = reg->name;
>> + pm8008_reg->rdesc.of_parse_cb = pm8008_regulator_of_parse;
>> + pm8008_reg->rdesc.uV_step = VSET_STEP_UV;
>> + pm8008_reg->rdesc.min_uV = reg->min_uv;
>> + pm8008_reg->rdesc.n_voltages
>> + = ((reg->max_uv - reg->min_uv)
>> + / pm8008_reg->rdesc.uV_step) + 1;
>> +
>> + pm8008_reg->rdesc.enable_reg = LDO_ENABLE_REG(base);
>> + pm8008_reg->rdesc.enable_mask = ENABLE_BIT;
>> + pm8008_reg->rdesc.min_dropout_uV = reg->min_dropout_uv;
>> +
>> + init_data->constraints.input_uV = init_data->constraints.max_uV;
>> + reg_config.dev = dev;
>> + reg_config.init_data = init_data;
>> + reg_config.driver_data = pm8008_reg;
>> + reg_config.of_node = pm8008_reg->of_node;
> I think we don't need to do this?
Right, I'll remove.
>> +
>> + return PTR_ERR_OR_ZERO(devm_regulator_register(dev, &pm8008_reg->rdesc,
>> + ®_config));
> Why are we returning here? Shouldn't we check return value and only
> return on failure and otherwise continue with registering the rest of
> the regulators?
My bad, I'll correct this.
>> + }
>> +
>> + return 0;
>> +}
>> +
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