[PATCH v2 2/2] iio: adc: Add Spreadtrum SC27XX PMICs ADC support
From: Baolin Wang
Date: Fri Jun 15 2018 - 03:03:58 EST
From: Freeman Liu <freeman.liu@xxxxxxxxxxxxxx>
The Spreadtrum SC27XX PMICs ADC controller contains 32 channels,
which is used to sample voltages with 12 bits conversion.
Signed-off-by: Freeman Liu <freeman.liu@xxxxxxxxxxxxxx>
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
---
Changes since v1:
- Add const for static structures definition.
- Change SC27XX_ADC_TO_VOLTAGE macro to be one function.
- Move channel scale accessing into mutex protection.
- Fix some typos.
---
drivers/iio/adc/Kconfig | 10 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/sc27xx_adc.c | 547 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 558 insertions(+)
create mode 100644 drivers/iio/adc/sc27xx_adc.c
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 9da7907..985b73e 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -621,6 +621,16 @@ config ROCKCHIP_SARADC
To compile this driver as a module, choose M here: the
module will be called rockchip_saradc.
+config SC27XX_ADC
+ tristate "Spreadtrum SC27xx series PMICs ADC"
+ depends on MFD_SC27XX_PMIC || COMPILE_TEST
+ help
+ Say yes here to build support for the integrated ADC inside the
+ Spreadtrum SC27xx series PMICs.
+
+ This driver can also be built as a module. If so, the module
+ will be called sc27xx_adc.
+
config SPEAR_ADC
tristate "ST SPEAr ADC"
depends on PLAT_SPEAR || COMPILE_TEST
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 28a9423..03db7b5 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
+obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
obj-$(CONFIG_STX104) += stx104.o
obj-$(CONFIG_SUN4I_GPADC) += sun4i-gpadc-iio.o
diff --git a/drivers/iio/adc/sc27xx_adc.c b/drivers/iio/adc/sc27xx_adc.c
new file mode 100644
index 0000000..52e5b74
--- /dev/null
+++ b/drivers/iio/adc/sc27xx_adc.c
@@ -0,0 +1,547 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Spreadtrum Communications Inc.
+
+#include <linux/hwspinlock.h>
+#include <linux/iio/iio.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* PMIC global registers definition */
+#define SC27XX_MODULE_EN 0xc08
+#define SC27XX_MODULE_ADC_EN BIT(5)
+#define SC27XX_ARM_CLK_EN 0xc10
+#define SC27XX_CLK_ADC_EN BIT(5)
+#define SC27XX_CLK_ADC_CLK_EN BIT(6)
+
+/* ADC controller registers definition */
+#define SC27XX_ADC_CTL 0x0
+#define SC27XX_ADC_CH_CFG 0x4
+#define SC27XX_ADC_DATA 0x4c
+#define SC27XX_ADC_INT_EN 0x50
+#define SC27XX_ADC_INT_CLR 0x54
+#define SC27XX_ADC_INT_STS 0x58
+#define SC27XX_ADC_INT_RAW 0x5c
+
+/* Bits and mask definition for SC27XX_ADC_CTL register */
+#define SC27XX_ADC_EN BIT(0)
+#define SC27XX_ADC_CHN_RUN BIT(1)
+#define SC27XX_ADC_12BIT_MODE BIT(2)
+#define SC27XX_ADC_RUN_NUM_MASK GENMASK(7, 4)
+#define SC27XX_ADC_RUN_NUM_SHIFT 4
+
+/* Bits and mask definition for SC27XX_ADC_CH_CFG register */
+#define SC27XX_ADC_CHN_ID_MASK GENMASK(4, 0)
+#define SC27XX_ADC_SCALE_MASK GENMASK(10, 8)
+#define SC27XX_ADC_SCALE_SHIFT 8
+
+/* Bits definitions for SC27XX_ADC_INT_EN registers */
+#define SC27XX_ADC_IRQ_EN BIT(0)
+
+/* Bits definitions for SC27XX_ADC_INT_CLR registers */
+#define SC27XX_ADC_IRQ_CLR BIT(0)
+
+/* Mask definition for SC27XX_ADC_DATA register */
+#define SC27XX_ADC_DATA_MASK GENMASK(11, 0)
+
+/* Timeout (ms) for the trylock of hardware spinlocks */
+#define SC27XX_ADC_HWLOCK_TIMEOUT 5000
+
+/* Maximum ADC channel number */
+#define SC27XX_ADC_CHANNEL_MAX 32
+
+/* ADC voltage ratio definition */
+#define SC27XX_VOLT_RATIO(n, d) \
+ (((n) << SC27XX_RATIO_NUMERATOR_OFFSET) | (d))
+#define SC27XX_RATIO_NUMERATOR_OFFSET 16
+#define SC27XX_RATIO_DENOMINATOR_MASK GENMASK(15, 0)
+
+struct sc27xx_adc_data {
+ struct device *dev;
+ struct regmap *regmap;
+ /*
+ * One hardware spinlock to synchronize between the multiple
+ * subsystems which will access the unique ADC controller.
+ */
+ struct hwspinlock *hwlock;
+ struct completion completion;
+ int channel_scale[SC27XX_ADC_CHANNEL_MAX];
+ int (*get_volt_ratio)(int channel, int scale);
+ u32 base;
+ int value;
+ int irq;
+};
+
+struct sc27xx_adc_linear_graph {
+ int volt0;
+ int adc0;
+ int volt1;
+ int adc1;
+};
+
+/*
+ * According to the datasheet, we can convert one ADC value to one voltage value
+ * through 2 points in the linear graph. If the voltage is less than 1.2v, we
+ * should use the small-scale graph, and if more than 1.2v, we should use the
+ * big-scale graph.
+ */
+static const struct sc27xx_adc_linear_graph big_scale_graph = {
+ 4200, 3310,
+ 3600, 2832,
+};
+
+static const struct sc27xx_adc_linear_graph small_scale_graph = {
+ 1000, 3413,
+ 100, 341,
+};
+
+static int sc27xx_adc_2731_ratio(int channel, int scale)
+{
+ switch (channel) {
+ case 1:
+ case 2:
+ case 3:
+ case 4:
+ return scale ? SC27XX_VOLT_RATIO(400, 1025) :
+ SC27XX_VOLT_RATIO(1, 1);
+ case 5:
+ return SC27XX_VOLT_RATIO(7, 29);
+ case 6:
+ return SC27XX_VOLT_RATIO(375, 9000);
+ case 7:
+ case 8:
+ return scale ? SC27XX_VOLT_RATIO(100, 125) :
+ SC27XX_VOLT_RATIO(1, 1);
+ case 19:
+ return SC27XX_VOLT_RATIO(1, 3);
+ default:
+ return SC27XX_VOLT_RATIO(1, 1);
+ }
+ return SC27XX_VOLT_RATIO(1, 1);
+}
+
+static int sc27xx_adc_read(struct sc27xx_adc_data *data, int channel,
+ int scale, int *val)
+{
+ int ret;
+ u32 tmp;
+
+ reinit_completion(&data->completion);
+
+ ret = hwspin_lock_timeout_raw(data->hwlock, SC27XX_ADC_HWLOCK_TIMEOUT);
+ if (ret) {
+ dev_err(data->dev, "timeout to get the hwspinlock\n");
+ return ret;
+ }
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
+ SC27XX_ADC_EN, SC27XX_ADC_EN);
+ if (ret)
+ goto unlock_adc;
+
+ /* Configure the channel id and scale */
+ tmp = (scale << SC27XX_ADC_SCALE_SHIFT) & SC27XX_ADC_SCALE_MASK;
+ tmp |= channel & SC27XX_ADC_CHN_ID_MASK;
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CH_CFG,
+ SC27XX_ADC_CHN_ID_MASK | SC27XX_ADC_SCALE_MASK,
+ tmp);
+ if (ret)
+ goto disable_adc;
+
+ /* Select 12bit conversion mode, and only sample 1 time */
+ tmp = SC27XX_ADC_12BIT_MODE;
+ tmp |= (0 << SC27XX_ADC_RUN_NUM_SHIFT) & SC27XX_ADC_RUN_NUM_MASK;
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
+ SC27XX_ADC_RUN_NUM_MASK | SC27XX_ADC_12BIT_MODE,
+ tmp);
+ if (ret)
+ goto disable_adc;
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
+ SC27XX_ADC_CHN_RUN, SC27XX_ADC_CHN_RUN);
+ if (ret)
+ goto disable_adc;
+
+ wait_for_completion(&data->completion);
+
+disable_adc:
+ regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
+ SC27XX_ADC_EN, 0);
+unlock_adc:
+ hwspin_unlock_raw(data->hwlock);
+
+ if (!ret)
+ *val = data->value;
+
+ return ret;
+}
+
+static irqreturn_t sc27xx_adc_isr(int irq, void *dev_id)
+{
+ struct sc27xx_adc_data *data = dev_id;
+ int ret;
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_CLR,
+ SC27XX_ADC_IRQ_CLR, SC27XX_ADC_IRQ_CLR);
+ if (ret)
+ return IRQ_RETVAL(ret);
+
+ ret = regmap_read(data->regmap, data->base + SC27XX_ADC_DATA,
+ &data->value);
+ if (ret)
+ return IRQ_RETVAL(ret);
+
+ data->value &= SC27XX_ADC_DATA_MASK;
+ complete(&data->completion);
+
+ return IRQ_HANDLED;
+}
+
+static void sc27xx_adc_volt_ratio(struct sc27xx_adc_data *data,
+ int channel, int scale,
+ u32 *div_numerator, u32 *div_denominator)
+{
+ u32 ratio = data->get_volt_ratio(channel, scale);
+
+ *div_numerator = ratio >> SC27XX_RATIO_NUMERATOR_OFFSET;
+ *div_denominator = ratio & SC27XX_RATIO_DENOMINATOR_MASK;
+}
+
+static int sc27xx_adc_to_volt(const struct sc27xx_adc_linear_graph *graph,
+ int raw_adc)
+{
+ int tmp;
+
+ tmp = (graph->volt0 - graph->volt1) * (raw_adc - graph->adc1);
+ tmp /= (graph->adc0 - graph->adc1);
+ tmp += graph->volt1;
+
+ return tmp < 0 ? 0 : tmp;
+}
+
+static int sc27xx_adc_convert_volt(struct sc27xx_adc_data *data, int channel,
+ int scale, int raw_adc)
+{
+ u32 numerator, denominator;
+ u32 volt;
+
+ /*
+ * Convert ADC values to voltage values according to the linear graph,
+ * and channel 5 and channel 1 has been calibrated, so we can just
+ * return the voltage values calculated by the linear graph. But other
+ * channels need be calculated to the real voltage values with the
+ * voltage ratio.
+ */
+ switch (channel) {
+ case 5:
+ return sc27xx_adc_to_volt(&big_scale_graph, raw_adc);
+
+ case 1:
+ return sc27xx_adc_to_volt(&small_scale_graph, raw_adc);
+
+ default:
+ volt = sc27xx_adc_to_volt(&small_scale_graph, raw_adc);
+ break;
+ }
+
+ sc27xx_adc_volt_ratio(data, channel, scale, &numerator, &denominator);
+
+ return (volt * denominator + numerator / 2) / numerator;
+}
+
+static int sc27xx_adc_read_processed(struct sc27xx_adc_data *data,
+ int channel, int scale, int *val)
+{
+ int ret, raw_adc;
+
+ ret = sc27xx_adc_read(data, channel, scale, &raw_adc);
+ if (ret)
+ return ret;
+
+ *val = sc27xx_adc_convert_volt(data, channel, scale, raw_adc);
+ return 0;
+}
+
+static int sc27xx_adc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct sc27xx_adc_data *data = iio_priv(indio_dev);
+ int scale, ret, tmp;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ case IIO_CHAN_INFO_AVERAGE_RAW:
+ mutex_lock(&indio_dev->mlock);
+ scale = data->channel_scale[chan->channel];
+ ret = sc27xx_adc_read(data, chan->channel, scale, &tmp);
+ mutex_unlock(&indio_dev->mlock);
+
+ if (ret)
+ return ret;
+
+ *val = tmp;
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_PROCESSED:
+ mutex_lock(&indio_dev->mlock);
+ scale = data->channel_scale[chan->channel];
+ ret = sc27xx_adc_read_processed(data, chan->channel, scale,
+ &tmp);
+ mutex_unlock(&indio_dev->mlock);
+
+ if (ret)
+ return ret;
+
+ *val = tmp;
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ mutex_lock(&indio_dev->mlock);
+ *val = data->channel_scale[chan->channel];
+ mutex_unlock(&indio_dev->mlock);
+ return IIO_VAL_INT;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int sc27xx_adc_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct sc27xx_adc_data *data = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ mutex_lock(&indio_dev->mlock);
+ data->channel_scale[chan->channel] = val;
+ mutex_unlock(&indio_dev->mlock);
+ return IIO_VAL_INT;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info sc27xx_info = {
+ .read_raw = &sc27xx_adc_read_raw,
+ .write_raw = &sc27xx_adc_write_raw,
+};
+
+#define SC27XX_ADC_CHANNEL(index) { \
+ .type = IIO_VOLTAGE, \
+ .channel = index, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
+ BIT(IIO_CHAN_INFO_PROCESSED) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+ .datasheet_name = "CH##index", \
+ .indexed = 1, \
+}
+
+static const struct iio_chan_spec sc27xx_channels[] = {
+ SC27XX_ADC_CHANNEL(0),
+ SC27XX_ADC_CHANNEL(1),
+ SC27XX_ADC_CHANNEL(2),
+ SC27XX_ADC_CHANNEL(3),
+ SC27XX_ADC_CHANNEL(4),
+ SC27XX_ADC_CHANNEL(5),
+ SC27XX_ADC_CHANNEL(6),
+ SC27XX_ADC_CHANNEL(7),
+ SC27XX_ADC_CHANNEL(8),
+ SC27XX_ADC_CHANNEL(9),
+ SC27XX_ADC_CHANNEL(10),
+ SC27XX_ADC_CHANNEL(11),
+ SC27XX_ADC_CHANNEL(12),
+ SC27XX_ADC_CHANNEL(13),
+ SC27XX_ADC_CHANNEL(14),
+ SC27XX_ADC_CHANNEL(15),
+ SC27XX_ADC_CHANNEL(16),
+ SC27XX_ADC_CHANNEL(17),
+ SC27XX_ADC_CHANNEL(18),
+ SC27XX_ADC_CHANNEL(19),
+ SC27XX_ADC_CHANNEL(20),
+ SC27XX_ADC_CHANNEL(21),
+ SC27XX_ADC_CHANNEL(22),
+ SC27XX_ADC_CHANNEL(23),
+ SC27XX_ADC_CHANNEL(24),
+ SC27XX_ADC_CHANNEL(25),
+ SC27XX_ADC_CHANNEL(26),
+ SC27XX_ADC_CHANNEL(27),
+ SC27XX_ADC_CHANNEL(28),
+ SC27XX_ADC_CHANNEL(29),
+ SC27XX_ADC_CHANNEL(30),
+ SC27XX_ADC_CHANNEL(31),
+};
+
+static int sc27xx_adc_enable(struct sc27xx_adc_data *data)
+{
+ int ret;
+
+ ret = regmap_update_bits(data->regmap, SC27XX_MODULE_EN,
+ SC27XX_MODULE_ADC_EN, SC27XX_MODULE_ADC_EN);
+ if (ret)
+ return ret;
+
+ /* Enable ADC work clock and controller clock */
+ ret = regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN,
+ SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN,
+ SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN);
+ if (ret)
+ return ret;
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_EN,
+ SC27XX_ADC_IRQ_EN, SC27XX_ADC_IRQ_EN);
+ if (ret)
+ return ret;
+
+ return regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_CLR,
+ SC27XX_ADC_IRQ_CLR, SC27XX_ADC_IRQ_CLR);
+}
+
+static void sc27xx_adc_disable(struct sc27xx_adc_data *data)
+{
+ regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_EN,
+ SC27XX_ADC_IRQ_EN, 0);
+
+ /* Disable ADC work clock and controller clock */
+ regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN,
+ SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN, 0);
+
+ regmap_update_bits(data->regmap, SC27XX_MODULE_EN,
+ SC27XX_MODULE_ADC_EN, 0);
+}
+
+static int sc27xx_adc_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct sc27xx_adc_data *sc27xx_data;
+ struct iio_dev *indio_dev;
+ const void *data;
+ int ret;
+
+ data = of_device_get_match_data(&pdev->dev);
+ if (!data) {
+ dev_err(&pdev->dev, "failed to get match data\n");
+ return -EINVAL;
+ }
+
+ indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*sc27xx_data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ sc27xx_data = iio_priv(indio_dev);
+
+ sc27xx_data->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ if (!sc27xx_data->regmap) {
+ dev_err(&pdev->dev, "failed to get ADC regmap\n");
+ return -ENODEV;
+ }
+
+ ret = of_property_read_u32(np, "reg", &sc27xx_data->base);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to get ADC base address\n");
+ return ret;
+ }
+
+ sc27xx_data->irq = platform_get_irq(pdev, 0);
+ if (sc27xx_data->irq < 0) {
+ dev_err(&pdev->dev, "failed to get ADC irq number\n");
+ return sc27xx_data->irq;
+ }
+
+ ret = of_hwspin_lock_get_id(np, 0);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to get hwspinlock id\n");
+ return ret;
+ }
+
+ sc27xx_data->hwlock = hwspin_lock_request_specific(ret);
+ if (!sc27xx_data->hwlock) {
+ dev_err(&pdev->dev, "failed to request hwspinlock\n");
+ return -ENXIO;
+ }
+
+ init_completion(&sc27xx_data->completion);
+
+ /*
+ * Different PMIC ADC controllers can have different channel voltage
+ * ratios, so we should save the implementation of getting voltage
+ * ratio for corresponding PMIC ADC in the device data structure.
+ */
+ sc27xx_data->get_volt_ratio = data;
+ sc27xx_data->dev = &pdev->dev;
+
+ ret = sc27xx_adc_enable(sc27xx_data);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable ADC module\n");
+ goto free_hwlock;
+ }
+
+ ret = devm_request_threaded_irq(&pdev->dev, sc27xx_data->irq, NULL,
+ sc27xx_adc_isr, IRQF_ONESHOT,
+ pdev->name, sc27xx_data);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request ADC irq\n");
+ goto disable_adc;
+ }
+
+ indio_dev->dev.parent = &pdev->dev;
+ indio_dev->name = dev_name(&pdev->dev);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &sc27xx_info;
+ indio_dev->channels = sc27xx_channels;
+ indio_dev->num_channels = ARRAY_SIZE(sc27xx_channels);
+ ret = devm_iio_device_register(&pdev->dev, indio_dev);
+ if (ret) {
+ dev_err(&pdev->dev, "could not register iio (ADC)");
+ goto disable_adc;
+ }
+
+ platform_set_drvdata(pdev, indio_dev);
+ return 0;
+
+disable_adc:
+ sc27xx_adc_disable(sc27xx_data);
+free_hwlock:
+ hwspin_lock_free(sc27xx_data->hwlock);
+ return ret;
+}
+
+static int sc27xx_adc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct sc27xx_adc_data *sc27xx_data = iio_priv(indio_dev);
+
+ sc27xx_adc_disable(sc27xx_data);
+ hwspin_lock_free(sc27xx_data->hwlock);
+ return 0;
+}
+
+static const struct of_device_id sc27xx_adc_of_match[] = {
+ {
+ .compatible = "sprd,sc2731-adc",
+ .data = (void *)&sc27xx_adc_2731_ratio,
+ },
+ { }
+};
+
+static struct platform_driver sc27xx_adc_driver = {
+ .probe = sc27xx_adc_probe,
+ .remove = sc27xx_adc_remove,
+ .driver = {
+ .name = "sc27xx-adc",
+ .of_match_table = sc27xx_adc_of_match,
+ },
+};
+
+module_platform_driver(sc27xx_adc_driver);
+
+MODULE_AUTHOR("Freeman Liu <freeman.liu@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Spreadtrum SC27XX ADC Driver");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5