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Date: Thu, 28 Oct 2021 13:19:30 -0700
From: Stephen Boyd <swboyd@...omium.org>
To: Bjorn Andersson <bjorn.andersson@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Satya Priya <quic_c_skakit@...cinc.com>
Cc: Liam Girdwood <lgirdwood@...il.com>,
Mark Brown <broonie@...nel.org>, collinsd@...eurora.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
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)
> +#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?
> + 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?
> + 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.
> + 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?
> + .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.
> + 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;
> + 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?
> + 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?
> +
> + 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?
> + }
> +
> + return 0;
> +}
> +
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