Marvell's 88PM886 PMIC has a so-called General Purpose ADC used for
monitoring various system voltages and temperatures. Add the relevant
register definitions to the MFD header and a driver for the ADC.
Signed-off-by: Duje Mihanović <d...@dujemihanovic.xyz>
---
v3:
- Add indices to pm886_gpadc_regs[] table
- Tidy up macro definitions
- Define MAX_REGISTER
- Drop some ternary operators
- raw_u{v,a} -> raw_u{V,A}
- Reorder gpadc_get_resistance_ohm()
- Split pm886_gpadc_setup() into hw_{en,dis}able()
- Set firmware node the right way
v2:
- default MFD_88PM886_PMIC
- u8[2] -> __be16
- Drop kernel.h include
- Add pm886_gpadc struct
- Reorder channel enum
- Drop GPADC voltage channels
- Drop unnecessary masking in gpadc_get_raw()
- Extend gpadc_enable_bias() to allow disabling bias
- usleep_range() -> fsleep()
- PM wrapper for pm886_gpadc_read_raw()
- Proper channel info: voltage is RAW | SCALE, temperature is RAW |
OFFSET | SCALE, resistance is PROCESSED
- Explicitly define channels to en/disable in pm886_gpadc_setup()
- Don't explicitly set iio->dev.parent
- Miscellaneous style changes
---
MAINTAINERS | 5 +
drivers/iio/adc/88pm886-gpadc.c | 388 ++++++++++++++++++++++++++++++++++++++++
drivers/iio/adc/Kconfig | 13 ++
drivers/iio/adc/Makefile | 1 +
include/linux/mfd/88pm886.h | 58 ++++++
5 files changed, 465 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index
6dcfbd11efef87927041f5cf58d70633dbb4b18d..0f7b78865c77967683ffc92f4822e722a4f723b6
100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14710,6 +14710,11 @@ F: drivers/regulator/88pm886-regulator.c
F: drivers/rtc/rtc-88pm886.c
F: include/linux/mfd/88pm886.h
+MARVELL 88PM886 PMIC GPADC DRIVER
+M: Duje Mihanović <d...@dujemihanovic.xyz>
+S: Maintained
+F: drivers/iio/adc/88pm886-gpadc.c
+
MARVELL ARMADA 3700 PHY DRIVERS
M: Miquel Raynal <miquel.ray...@bootlin.com>
S: Maintained
diff --git a/drivers/iio/adc/88pm886-gpadc.c b/drivers/iio/adc/88pm886-gpadc.c
new file mode 100644
index
0000000000000000000000000000000000000000..8c1fa99b94415f5f193ec65d313fab5001f40d58
--- /dev/null
+++ b/drivers/iio/adc/88pm886-gpadc.c
@@ -0,0 +1,388 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2025, Duje Mihanović <d...@dujemihanovic.xyz>
+ */
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+#include <linux/units.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/types.h>
+
+#include <linux/mfd/88pm886.h>
+
+struct pm886_gpadc {
+ struct regmap *map;
+};
+
+enum pm886_gpadc_channel {
+ VSC_CHAN,
+ VCHG_PWR_CHAN,
+ VCF_OUT_CHAN,
+ VBAT_CHAN,
+ VBAT_SLP_CHAN,
+ VBUS_CHAN,
+
+ GPADC0_CHAN,
+ GPADC1_CHAN,
+ GPADC2_CHAN,
+ GPADC3_CHAN,
+
+ GND_DET1_CHAN,
+ GND_DET2_CHAN,
+ MIC_DET_CHAN,
+
+ TINT_CHAN,
+};
+
+static const int pm886_gpadc_regs[] = {
+ [VSC_CHAN] = PM886_REG_GPADC_VSC,
+ [VCHG_PWR_CHAN] = PM886_REG_GPADC_VCHG_PWR,
+ [VCF_OUT_CHAN] = PM886_REG_GPADC_VCF_OUT,
+ [VBAT_CHAN] = PM886_REG_GPADC_VBAT,
+ [VBAT_SLP_CHAN] = PM886_REG_GPADC_VBAT_SLP,
+ [VBUS_CHAN] = PM886_REG_GPADC_VBUS,
+
+ [GPADC0_CHAN] = PM886_REG_GPADC_GPADC0,
+ [GPADC1_CHAN] = PM886_REG_GPADC_GPADC1,
+ [GPADC2_CHAN] = PM886_REG_GPADC_GPADC2,
+ [GPADC3_CHAN] = PM886_REG_GPADC_GPADC3,
+
+ [GND_DET1_CHAN] = PM886_REG_GPADC_GND_DET1,
+ [GND_DET2_CHAN] = PM886_REG_GPADC_GND_DET2,
+ [MIC_DET_CHAN] = PM886_REG_GPADC_MIC_DET,
+
+ [TINT_CHAN] = PM886_REG_GPADC_TINT,
+};
+
+#define ADC_CHANNEL_VOLTAGE(index, lsb, name) \
+{ \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = index, \
+ .address = lsb, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+ .datasheet_name = name, \
+}
+
+#define ADC_CHANNEL_RESISTANCE(index, lsb, name) \
+{ \
+ .type = IIO_RESISTANCE, \
+ .indexed = 1, \
+ .channel = index, \
+ .address = lsb, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
+ .datasheet_name = name, \
+}
+
+#define ADC_CHANNEL_TEMPERATURE(index, lsb, name) \
+{ \
+ .type = IIO_TEMP, \
+ .indexed = 1, \
+ .channel = index, \
+ .address = lsb, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_OFFSET), \
+ .datasheet_name = name, \
+}
+
+static const struct iio_chan_spec pm886_gpadc_channels[] = {
+ ADC_CHANNEL_VOLTAGE(VSC_CHAN, 1367, "vsc"),
+ ADC_CHANNEL_VOLTAGE(VCHG_PWR_CHAN, 1709, "vchg_pwr"),
+ ADC_CHANNEL_VOLTAGE(VCF_OUT_CHAN, 1367, "vcf_out"),
+ ADC_CHANNEL_VOLTAGE(VBAT_CHAN, 1367, "vbat"),
+ ADC_CHANNEL_VOLTAGE(VBAT_SLP_CHAN, 1367, "vbat_slp"),
+ ADC_CHANNEL_VOLTAGE(VBUS_CHAN, 1709, "vbus"),
+
+ ADC_CHANNEL_RESISTANCE(GPADC0_CHAN, 342, "gpadc0"),
+ ADC_CHANNEL_RESISTANCE(GPADC1_CHAN, 342, "gpadc1"),
+ ADC_CHANNEL_RESISTANCE(GPADC2_CHAN, 342, "gpadc2"),
+ ADC_CHANNEL_RESISTANCE(GPADC3_CHAN, 342, "gpadc3"),
+
+ ADC_CHANNEL_VOLTAGE(GND_DET1_CHAN, 342, "gnddet1"),
+ ADC_CHANNEL_VOLTAGE(GND_DET2_CHAN, 342, "gnddet2"),
+ ADC_CHANNEL_VOLTAGE(MIC_DET_CHAN, 1367, "mic_det"),
+
+ ADC_CHANNEL_TEMPERATURE(TINT_CHAN, 104, "tint"),
+};
+
+static const struct regmap_config pm886_gpadc_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = PM886_GPADC_MAX_REGISTER,
+};
+
+static int gpadc_get_raw(struct iio_dev *iio, enum pm886_gpadc_channel chan)
+{
+ struct pm886_gpadc *gpadc = iio_priv(iio);
+ __be16 buf;
+ int ret;
+
+ ret = regmap_bulk_read(gpadc->map, pm886_gpadc_regs[chan], &buf,
sizeof(buf));
+ if (ret)
+ return ret;
+
+ return be16_to_cpu(buf) >> 4;
+}
+
+static int
+gpadc_set_bias(struct pm886_gpadc *gpadc, enum pm886_gpadc_channel chan, bool
on)
+{
+ unsigned int gpadc_num = chan - GPADC0_CHAN;
+ unsigned int bits = BIT(gpadc_num + 4) | BIT(gpadc_num);
+
+ return regmap_assign_bits(gpadc->map, PM886_REG_GPADC_CONFIG(0x14),
bits, on);
+}
+
+static int
+gpadc_find_bias_current(struct iio_dev *iio, struct iio_chan_spec const *chan,
+ unsigned int *raw_uV, unsigned int *raw_uA)
+{
+ struct pm886_gpadc *gpadc = iio_priv(iio);
+ unsigned int gpadc_num = chan->channel - GPADC0_CHAN;
+ unsigned int reg = PM886_REG_GPADC_CONFIG(0xb + gpadc_num);
+ unsigned long lsb = chan->address;
+ int ret;
+
+ for (unsigned int i = 0; i < PM886_GPADC_BIAS_LEVELS; i++) {
+ ret = regmap_update_bits(gpadc->map, reg, GENMASK(3, 0), i);
+ if (ret)
+ return ret;
+
+ /* Wait for the new bias level to apply. */
+ fsleep(5 * USEC_PER_MSEC);
+
+ *raw_uA = PM886_GPADC_INDEX_TO_BIAS_uA(i);
+ *raw_uV = gpadc_get_raw(iio, chan->channel) * lsb;
+
+ /*
+ * Vendor kernel errors out above 1.25V, but testing shows that
+ * the resistance of the battery detection channel (GPADC2 on
+ * coreprimevelte) reaches about 1.4Mohm when the battery is
+ * removed, which can't be measured with such a low upper
+ * limit. Therefore, to be able to detect the battery without
+ * ugly externs as used in the vendor fuelgauge driver,
+ * increase this limit a bit.
+ */
+ if (WARN_ON(*raw_uV > 1500 * (MICRO / MILLI)))
+ return -EIO;
+
+ /*
+ * Vendor kernel errors out under 300mV, but for the same
+ * reason as above (except the channel hovers around 3.5kohm
+ * with battery present) reduce this limit.
+ */
+ if (*raw_uV < 200 * (MICRO / MILLI)) {
+ dev_dbg(&iio->dev, "bad bias for chan %d: %duA @
%duV\n", chan->channel,
+ *raw_uA, *raw_uV);
+ continue;
+ }
+
+ dev_dbg(&iio->dev, "good bias for chan %d: %duA @ %duV\n",
chan->channel,
+ *raw_uA, *raw_uV);
+ return 0;
+ }
+
+ dev_err(&iio->dev, "failed to find good bias for chan %d\n",
chan->channel);
+ return -EINVAL;
+}
+
+static int
+gpadc_get_resistance_ohm(struct iio_dev *iio, struct iio_chan_spec const *chan)
+{
+ struct pm886_gpadc *gpadc = iio_priv(iio);
+ unsigned int raw_uV, raw_uA;
+ int ret;
+
+ ret = gpadc_set_bias(gpadc, chan->channel, true);
+ if (ret)
+ goto out;
+
+ ret = gpadc_find_bias_current(iio, chan, &raw_uV, &raw_uA);
+ if (ret)
+ goto out;
+
+ ret = DIV_ROUND_CLOSEST(raw_uV, raw_uA);
+out:
+ gpadc_set_bias(gpadc, chan->channel, false);
+ return ret;
+}
+
+static int
+__pm886_gpadc_read_raw(struct iio_dev *iio, struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ unsigned long lsb = chan->address;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ *val = gpadc_get_raw(iio, chan->channel);
+ if (*val < 0)
+ return *val;
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = lsb;
+
+ if (chan->type == IIO_VOLTAGE) {
+ *val2 = MILLI;
+ return IIO_VAL_FRACTIONAL;
+ } else {
+ return IIO_VAL_INT;
+ }
+ case IIO_CHAN_INFO_OFFSET:
+ /* Raw value is 104 millikelvin/LSB, convert it to 104
millicelsius/LSB */
+ *val = ABSOLUTE_ZERO_MILLICELSIUS;
+ *val2 = lsb;
+ return IIO_VAL_FRACTIONAL;
+ case IIO_CHAN_INFO_PROCESSED:
+ *val = gpadc_get_resistance_ohm(iio, chan);
+ if (*val < 0)
+ return *val;
+
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int pm886_gpadc_read_raw(struct iio_dev *iio, struct iio_chan_spec
const *chan,
+ int *val, int *val2, long mask)
+{
+ struct device *dev = iio->dev.parent;
+ int ret;
+
+ ret = pm_runtime_resume_and_get(dev);
+ if (ret)
+ return ret;
+
+ ret = __pm886_gpadc_read_raw(iio, chan, val, val2, mask);
+
+ pm_runtime_put_autosuspend(dev);
+ return ret;
+}
+
+static int pm886_gpadc_hw_enable(struct regmap *map)
+{
+ const u8 config[] = {
+ PM886_GPADC_CONFIG1_EN_ALL,
+ PM886_GPADC_CONFIG2_EN_ALL,
+ PM886_GPADC_GND_DET2_EN,
+ };
+ int ret;
+
+ /* Enable the ADC block. */
+ ret = regmap_set_bits(map, PM886_REG_GPADC_CONFIG(0x6), BIT(0));
+ if (ret)
+ return ret;
+
+ /* Enable all channels. */
+ return regmap_bulk_write(map, PM886_REG_GPADC_CONFIG(0x1), config,
ARRAY_SIZE(config));
+}
+
+static int pm886_gpadc_hw_disable(struct regmap *map)
+{
+ return regmap_clear_bits(map, PM886_REG_GPADC_CONFIG(0x6), BIT(0));
+}
+
+static const struct iio_info pm886_gpadc_iio_info = {
+ .read_raw = pm886_gpadc_read_raw,
+};
+
+static int pm886_gpadc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct pm886_chip *chip = dev_get_drvdata(dev->parent);
+ struct i2c_client *client = chip->client;
+ struct pm886_gpadc *gpadc;
+ struct i2c_client *page;
+ struct iio_dev *iio;
+ int ret;
+
+ iio = devm_iio_device_alloc(dev, sizeof(*gpadc));
+ if (!iio)
+ return -ENOMEM;
+
+ gpadc = iio_priv(iio);
+ dev_set_drvdata(dev, iio);
+
+ page = devm_i2c_new_dummy_device(dev, client->adapter,
+ client->addr +
PM886_PAGE_OFFSET_GPADC);
+ if (IS_ERR(page))
+ return dev_err_probe(dev, PTR_ERR(page), "Failed to initialize
GPADC page\n");
+
+ gpadc->map = devm_regmap_init_i2c(page, &pm886_gpadc_regmap_config);
+ if (IS_ERR(gpadc->map))
+ return dev_err_probe(dev, PTR_ERR(gpadc->map),
+ "Failed to initialize GPADC regmap\n");
+
+ iio->name = "88pm886-gpadc";
+ iio->modes = INDIO_DIRECT_MODE;
+ iio->info = &pm886_gpadc_iio_info;
+ iio->channels = pm886_gpadc_channels;
+ iio->num_channels = ARRAY_SIZE(pm886_gpadc_channels);
+ device_set_node(&iio->dev, dev_fwnode(dev->parent));
+
+ ret = devm_pm_runtime_enable(dev);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to enable runtime PM\n");
+
+ pm_runtime_set_autosuspend_delay(dev, 50);
+ pm_runtime_use_autosuspend(dev);
+ ret = devm_iio_device_register(dev, iio);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to register ADC\n");
+
+ return 0;
+}
+
+static int pm886_gpadc_runtime_resume(struct device *dev)
+{
+ struct iio_dev *iio = dev_get_drvdata(dev);
+ struct pm886_gpadc *gpadc = iio_priv(iio);
+
+ return pm886_gpadc_hw_enable(gpadc->map);
+}
+
+static int pm886_gpadc_runtime_suspend(struct device *dev)
+{
+ struct iio_dev *iio = dev_get_drvdata(dev);
+ struct pm886_gpadc *gpadc = iio_priv(iio);
+
+ return pm886_gpadc_hw_disable(gpadc->map);
+}
+
+static DEFINE_RUNTIME_DEV_PM_OPS(pm886_gpadc_pm_ops,
+ pm886_gpadc_runtime_suspend,
+ pm886_gpadc_runtime_resume, NULL);
+
+static const struct platform_device_id pm886_gpadc_id[] = {
+ { "88pm886-gpadc" },
+ { }
+};
+MODULE_DEVICE_TABLE(platform, pm886_gpadc_id);
+
+static struct platform_driver pm886_gpadc_driver = {
+ .driver = {
+ .name = "88pm886-gpadc",
+ .pm = pm_ptr(&pm886_gpadc_pm_ops),
+ },
+ .probe = pm886_gpadc_probe,
+ .id_table = pm886_gpadc_id,
+};
+module_platform_driver(pm886_gpadc_driver);
+
+MODULE_AUTHOR("Duje Mihanović <d...@dujemihanovic.xyz>");
+MODULE_DESCRIPTION("Marvell 88PM886 GPADC driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index
24f2572c487ea3db2abec3283ebd93357c08baab..04c8478ff707dd16ec943674ac7f01f33249acf1
100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -9,6 +9,19 @@ menu "Analog to digital converters"
config IIO_ADC_HELPER
tristate
+config 88PM886_GPADC
+ tristate "Marvell 88PM886 GPADC driver"
+ depends on MFD_88PM886_PMIC
+ default MFD_88PM886_PMIC
+ help
+ Say Y here to enable support for the GPADC (General Purpose ADC)
+ found on the Marvell 88PM886 PMIC. The GPADC measures various
+ internal voltages and temperatures, including (but not limited to)
+ system, battery and USB Vbus.
+
+ To compile this driver as a module, choose M here: the module will be
+ called 88pm886-gpadc.
+
config AB8500_GPADC
bool "ST-Ericsson AB8500 GPADC driver"
depends on AB8500_CORE && REGULATOR_AB8500
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index
1c6ca5fd4b6db8c4c40a351b231ba0892e8cd70e..64854907bf3bef7da39f95247e4e502d01232af3
100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -6,6 +6,7 @@
obj-$(CONFIG_IIO_ADC_HELPER) += industrialio-adc.o
# When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_88PM886_GPADC) += 88pm886-gpadc.o
obj-$(CONFIG_AB8500_GPADC) += ab8500-gpadc.o
obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
obj-$(CONFIG_AD4000) += ad4000.o
diff --git a/include/linux/mfd/88pm886.h b/include/linux/mfd/88pm886.h
index
85eca44f39ab58ba4cb9ec4216118ee9604d021f..38892ba7b8a42bbecb53621a891a52a2fd70fd43
100644
--- a/include/linux/mfd/88pm886.h
+++ b/include/linux/mfd/88pm886.h
@@ -10,6 +10,7 @@
#define PM886_IRQ_ONKEY 0
#define PM886_PAGE_OFFSET_REGULATORS 1
+#define PM886_PAGE_OFFSET_GPADC 2
#define PM886_REG_ID 0x00
@@ -70,6 +71,63 @@
#define PM886_LDO_VSEL_MASK 0x0f
#define PM886_BUCK_VSEL_MASK 0x7f
+/* GPADC enable/disable registers */
+#define PM886_REG_GPADC_CONFIG(n) (n)
+
+#define PM886_GPADC_VSC_EN BIT(0)
+#define PM886_GPADC_VBAT_EN BIT(1)
+#define PM886_GPADC_GNDDET1_EN BIT(3)
+#define PM886_GPADC_VBUS_EN BIT(4)
+#define PM886_GPADC_VCHG_PWR_EN BIT(5)
+#define PM886_GPADC_VCF_OUT_EN BIT(6)
+#define PM886_GPADC_CONFIG1_EN_ALL \
+ (PM886_GPADC_VSC_EN | \
+ PM886_GPADC_VBAT_EN | \
+ PM886_GPADC_GNDDET1_EN | \
+ PM886_GPADC_VBUS_EN | \
+ PM886_GPADC_VCHG_PWR_EN | \
+ PM886_GPADC_VCF_OUT_EN)
+
+#define PM886_GPADC_TINT_EN BIT(0)
+#define PM886_GPADC_PMODE_EN BIT(1)
+#define PM886_GPADC_GPADC0_EN BIT(2)
+#define PM886_GPADC_GPADC1_EN BIT(3)
+#define PM886_GPADC_GPADC2_EN BIT(4)
+#define PM886_GPADC_GPADC3_EN BIT(5)
+#define PM886_GPADC_MIC_DET_EN BIT(6)
+#define PM886_GPADC_CONFIG2_EN_ALL \
+ (PM886_GPADC_TINT_EN | \
+ PM886_GPADC_GPADC0_EN | \
+ PM886_GPADC_GPADC1_EN | \
+ PM886_GPADC_GPADC2_EN | \
+ PM886_GPADC_GPADC3_EN | \
+ PM886_GPADC_MIC_DET_EN)
+
+/* No CONFIG3_EN_ALL because this is the only bit there. */
+#define PM886_GPADC_GND_DET2_EN BIT(0)
+
+/* GPADC channel registers */
+#define PM886_REG_GPADC_VSC 0x40
+#define PM886_REG_GPADC_VCHG_PWR 0x4c
+#define PM886_REG_GPADC_VCF_OUT 0x4e
+#define PM886_REG_GPADC_TINT 0x50
+#define PM886_REG_GPADC_GPADC0 0x54
+#define PM886_REG_GPADC_GPADC1 0x56
+#define PM886_REG_GPADC_GPADC2 0x58
+#define PM886_REG_GPADC_VBAT 0xa0
+#define PM886_REG_GPADC_GND_DET1 0xa4
+#define PM886_REG_GPADC_GND_DET2 0xa6
+#define PM886_REG_GPADC_VBUS 0xa8
+#define PM886_REG_GPADC_GPADC3 0xaa
+#define PM886_REG_GPADC_MIC_DET 0xac
+#define PM886_REG_GPADC_VBAT_SLP 0xb0
+
+/* VBAT_SLP is the last register and is 2 bytes wide like other channels. */
+#define PM886_GPADC_MAX_REGISTER (PM886_REG_GPADC_VBAT_SLP + 1)
+
+#define PM886_GPADC_BIAS_LEVELS 16
+#define PM886_GPADC_INDEX_TO_BIAS_uA(i) (1 + (i) * 5)
+
struct pm886_chip {
struct i2c_client *client;
unsigned int chip_id;
--
2.51.0
