Re: [PATCH V2 3/4] regulator: Add a regulator driver for the PM8008 PMIC
From: skakit
Date: Fri Oct 22 2021 - 08:29:02 EST
On 2021-10-06 00:05, Stephen Boyd wrote:
Quoting Satya Priya (2021-09-30 21:00:58)
diff --git a/drivers/regulator/qcom-pm8008-regulator.c
b/drivers/regulator/qcom-pm8008-regulator.c
new file mode 100644
index 0000000..5dacaa4
--- /dev/null
+++ b/drivers/regulator/qcom-pm8008-regulator.c
@@ -0,0 +1,320 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2021, The Linux Foundation. All rights reserved. */
+
+#include <linux/delay.h>
Is this include used?
No will remove.
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
Is this include used?
No
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
Is this include used?
No
+#include <linux/pm.h>
Is this include used?
No
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/string.h>
Is this include used? Probably should just be kernel.h?
string.h is not used , will change it as kernel.h
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
Is this include used?
Yes it is used. For of_get_regulator_init_data().
+
+#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)
+#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 STEP_RATE_MASK GENMASK(1, 0)
+
+#define PM8008_MAX_LDO 7
Drop define.
ok.
+
+struct regulator_data {
+ char *name;
const?
ok
+ char *supply_name;
const?
ok
+ 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;
+ u16 base;
+ int step_rate;
+};
+
+static const struct regulator_data reg_data[PM8008_MAX_LDO] = {
Use [] instead of PM8008_MAX_LDO.
Ok.
+ /* 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},
Nitpick: Put a space after { and before } to match kernel style.
Okay.
+};
+
+static int pm8008_read(struct regmap *regmap, u16 reg, u8 *val, int
count)
+{
+ int rc;
+
+ rc = regmap_bulk_read(regmap, reg, val, count);
+ if (rc < 0)
+ pr_err("failed to read %#x, rc=%d\n", reg, rc);
+
+ return rc;
+}
+
+static int pm8008_write(struct regmap *regmap, u16 reg, u8 *val, int
count)
+{
+ int rc;
+
+ pr_debug("Writing [%*ph] from address %#x\n", count, val,
reg);
Don't we already have regmap debugging facilities for this? Why
duplicate it in this driver?
+ rc = regmap_bulk_write(regmap, reg, val, count);
+ if (rc < 0)
+ pr_err("failed to write %#x rc=%d\n", reg, rc);
+
+ return rc;
+}
The above two functions should just be inlined.
I am planning to remove these 2 APIs and use regmap_bulk_read/write
directly.
+
+static int pm8008_regulator_get_voltage(struct regulator_dev *rdev)
+{
+ struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+ u8 vset_raw[2];
+ int rc;
+
+ rc = pm8008_read(pm8008_reg->regmap,
+ LDO_VSET_LB_REG(pm8008_reg->base),
+ vset_raw, 2);
Can this be an __le16 mV?
Below is the diff after changing as per your suggestion, Please correct
me if wrong.
- u8 vset_raw[2];
+ __le16 mV;
int rc;
- rc = pm8008_read(pm8008_reg->regmap,
- LDO_VSET_LB_REG(pm8008_reg->base),
- vset_raw, 2);
+ rc = regmap_bulk_read(pm8008_reg->regmap,
+ LDO_VSET_LB_REG(pm8008_reg->base), &mV, 2);
if (rc < 0) {
dev_err(pm8008_reg->dev, "failed to read regulator
voltage rc=%d\n", rc);
return rc;
}
- return (vset_raw[1] << 8 | vset_raw[0]) * 1000;
+ return le16_to_cpu(mV) * 1000;
+ if (rc < 0) {
+ dev_err(pm8008_reg->dev, "failed to read regulator
voltage rc=%d\n", rc);
+ return rc;
+ }
+
+ return (vset_raw[1] << 8 | vset_raw[0]) * 1000;
And then 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 = 0, mv;
+ u8 vset_raw[2];
+
+ 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[0] = mv & 0xff;
+ vset_raw[1] = (mv & 0xff00) >> 8;
Make vset_raw a u16?
vset = mv;
And then use cpu_to_le16() below?
Below is the diff:
- int rc = 0, mv;
- u8 vset_raw[2];
+ int rc, mv;
+ u16 vset_raw;
[...]
- vset_raw[0] = mv & 0xff;
- vset_raw[1] = (mv & 0xff00) >> 8;
- rc = pm8008_write(pm8008_reg->regmap,
LDO_VSET_LB_REG(pm8008_reg->base),
- vset_raw, 2);
+ vset_raw = cpu_to_le16(mv);
+
+ rc = regmap_bulk_write(pm8008_reg->regmap,
+ LDO_VSET_LB_REG(pm8008_reg->base), &vset_raw,
+ sizeof(vset_raw));
+ rc = pm8008_write(pm8008_reg->regmap,
LDO_VSET_LB_REG(pm8008_reg->base),
+ vset_raw, 2);
regmap_bulk_write(pm8008_reg->regmap,
LDO_VSET_LB_REG(pm8008_reg->base),
cpu_to_le16(vset), sizeof(vset));
does it work?
It is working fine after modifying as above.
+ if (rc < 0) {
+ dev_err(pm8008_reg->dev, "failed to write voltage
rc=%d\n", rc);
+ 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,
Weird tabbing.
Will correct it.
+ .disable = regulator_disable_regmap,
+ .is_enabled = regulator_is_enabled_regmap,
+ .set_voltage = pm8008_regulator_set_voltage,
+ .get_voltage = pm8008_regulator_get_voltage,
+ .list_voltage = regulator_list_voltage_linear,
+ .set_voltage_time = pm8008_regulator_set_voltage_time,
+};
+
+static int pm8008_register_ldo(struct pm8008_regulator *pm8008_reg,
+ const char *name)
+{
+ struct regulator_config reg_config = {};
+ struct regulator_init_data *init_data;
+ struct device *dev = pm8008_reg->dev;
+ struct device_node *reg_node = pm8008_reg->of_node;
+ int rc, i;
+ u32 base = 0;
+ u8 reg;
+
+ /* get regulator data */
+ for (i = 0; i < PM8008_MAX_LDO; i++)
Use ARRAY_SIZE()
Ok.
+ if (strstr(name, reg_data[i].name))
+ break;
+
+ if (i == PM8008_MAX_LDO) {
+ dev_err(dev, "Invalid regulator name %s\n", name);
+ return -EINVAL;
+ }
+
+ rc = of_property_read_u32(reg_node, "reg", &base);
+ if (rc < 0) {
+ dev_err(dev, "%s: failed to get regulator base
rc=%d\n", name, rc);
+ return rc;
+ }
+ pm8008_reg->base = base;
+
+ /* get slew rate */
+ rc = pm8008_read(pm8008_reg->regmap,
+ LDO_STEPPER_CTL_REG(pm8008_reg->base), ®,
1);
+ if (rc < 0) {
+ dev_err(dev, "%s: failed to read step rate
configuration rc=%d\n",
+ name, rc);
+ return rc;
+ }
+ pm8008_reg->step_rate = 38400 >> (reg & STEP_RATE_MASK);
Where does 38400 come from? Is that a frequency?
It is the default voltage step rate. I'll add a macro
DEFAULT_VOLTAGE_STEP_RATE for this to be clear.
+
+ init_data = of_get_regulator_init_data(dev, reg_node,
+ &pm8008_reg->rdesc);
+ if (init_data == NULL) {
if (!init_data)
is more kernel style.
Okay.
+ dev_err(dev, "%s: failed to get regulator data\n",
name);
+ return -ENODATA;
+ }
+
+ 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 = reg_node;
+
+ 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_data[i].supply_name;
+ pm8008_reg->rdesc.uV_step = VSET_STEP_UV;
+ pm8008_reg->rdesc.min_uV = reg_data[i].min_uv;
+ pm8008_reg->rdesc.n_voltages
+ = ((reg_data[i].max_uv - reg_data[i].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_data[i].min_dropout_uv;
+ of_property_read_u32(reg_node, "qcom,min-dropout-voltage",
+ &pm8008_reg->rdesc.min_dropout_uV);
Why do we allow DT to override this? Isn't it a property of the
hardware
that doesn't change? So the driver can hardcode the knowledge about the
dropout.
The headroom values change with targets. We are adding some default
headroom values in the driver and later overwriting them with the actual
values specified in the DT.
+
+ pm8008_reg->rdev = devm_regulator_register(dev,
&pm8008_reg->rdesc,
Is this assignment ever used? Seems like it would be better to merely
return PTR_ERR_OR_ZERO(devm_regulator_register(dev, ...));
Okay.
+ ®_config);
+ if (IS_ERR(pm8008_reg->rdev)) {
+ rc = PTR_ERR(pm8008_reg->rdev);
+ dev_err(dev, "%s: failed to register regulator
rc=%d\n",
+ pm8008_reg->rdesc.name, rc);
+ return rc;
+ }
+
+ dev_dbg(dev, "%s regulator registered\n", name);
+
+ return 0;
+}
+
+static int pm8008_parse_regulator(struct regmap *regmap, struct
device *dev)
+{
+ int rc = 0;
Drop initialization.
Okay.
+ const char *name;
+ struct device_node *child;
+ struct pm8008_regulator *pm8008_reg;
+
+ /* parse each subnode and register regulator for regulator
child */
+ for_each_available_child_of_node(dev->of_node, child) {
+ pm8008_reg = devm_kzalloc(dev, sizeof(*pm8008_reg),
GFP_KERNEL);
+
+ pm8008_reg->regmap = regmap;
+ pm8008_reg->of_node = child;
+ pm8008_reg->dev = dev;
+
+ rc = of_property_read_string(child, "regulator-name",
&name);
+ if (rc)
+ continue;
+
+ rc = pm8008_register_ldo(pm8008_reg, name);
Can we use the of_parse_cb similar to qcom_spmi-regulator.c?
Are you suggesting to remove the pm8008_register_ldo API and add its
contents in probe itself and then use of_parse_cb callback like in
qcom_spmi-regulator.c?
Do we have any advantage using that here? Also I am not exactly sure
what all contents to put in that. Seems like we can put the step rate
and min-dropout-voltage configurations in there.
+ if (rc < 0) {
+ dev_err(dev, "failed to register regulator %s
rc=%d\n",
+ name, rc);
+ return rc;
+ }
+ }
+
+ return 0;
+}
+
+static int pm8008_regulator_probe(struct platform_device *pdev)
+{
+ int rc = 0;
Please don't initialize locals and then overwrite them before testing
them.
+ struct regmap *regmap;
+
+ regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ if (!regmap) {
+ dev_err(&pdev->dev, "parent regmap is missing\n");
+ return -EINVAL;
+ }
+
+ rc = pm8008_parse_regulator(regmap, &pdev->dev);
Just inline this code. It's basically the entire probe function so
splitting it away to yet another function just makes it harder to read.
Okay.
+ if (rc < 0) {
+ dev_err(&pdev->dev, "failed to parse device tree
rc=%d\n", rc);
+ return rc;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id pm8008_regulator_match_table[] = {
+ { .compatible = "qcom,pm8008-regulator", },
+ { },
Nitpick: Drop comma on sentinel so nothing can come after without
causing a compilation error.
Okay
+};
Add a MODULE_DEVICE_TABLE please. Same comment applies to the mfd
driver.
Okay
+
+static struct platform_driver pm8008_regulator_driver = {
+ .driver = {
+ .name = "qcom,pm8008-regulator",
+ .of_match_table = pm8008_regulator_match_table,
+ },
+ .probe = pm8008_regulator_probe,
I have no idea what's going on with this tabbing.
+};
+
+module_platform_driver(pm8008_regulator_driver);
+