[PATCH 2/2] iio: adc: Add driver for Renesas RZ/G2L A/D converter

From: Lad Prabhakar
Date: Tue Jun 29 2021 - 18:04:00 EST

Add ADC driver support for Renesas RZ/G2L A/D converter in SW
trigger mode.

A/D Converter block is a successive approximation analog-to-digital
converter with a 12-bit accuracy and supports a maximum of 8 input
channels.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
Reviewed-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
MAINTAINERS | 8 +
drivers/iio/adc/Kconfig | 10 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/rzg2l_adc.c | 489 ++++++++++++++++++++++++++++++++++++
4 files changed, 508 insertions(+)
create mode 100644 drivers/iio/adc/rzg2l_adc.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 81e1edeceae4..bee4c3847e01 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15622,6 +15622,14 @@ L: linux-renesas-soc@xxxxxxxxxxxxxxx
S: Maintained
F: drivers/phy/renesas/phy-rcar-gen3-usb*.c

+RENESAS RZ/G2L A/D DRIVER
+M: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
+L: linux-iio@xxxxxxxxxxxxxxx
+L: linux-renesas-soc@xxxxxxxxxxxxxxx
+S: Supported
+F: Documentation/devicetree/bindings/iio/adc/renesas,rzg2l-adc.yaml
+F: drivers/iio/adc/rzg2l_adc.c
+
RESET CONTROLLER FRAMEWORK
M: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
S: Maintained
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index c7946c439612..9408cbf97acc 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -887,6 +887,16 @@ config ROCKCHIP_SARADC
To compile this driver as a module, choose M here: the
module will be called rockchip_saradc.

+config RZG2L_ADC
+ tristate "Renesas RZ/G2L ADC driver"
+ depends on ARCH_R9A07G044 || COMPILE_TEST
+ help
+ Say yes here to build support for the ADC found in Renesas
+ RZ/G2L family.
+
+ To compile this driver as a module, choose M here: the
+ module will be called rzg2l_adc.
+
config SC27XX_ADC
tristate "Spreadtrum SC27xx series PMICs ADC"
depends on MFD_SC27XX_PMIC || COMPILE_TEST
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index a226657d19c0..d92bcc9c5fbb 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
obj-$(CONFIG_RN5T618_ADC) += rn5t618-adc.o
obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
+obj-$(CONFIG_RZG2L_ADC) += rzg2l_adc.o
obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
obj-$(CONFIG_STX104) += stx104.o
diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
new file mode 100644
index 000000000000..1c58eb8ae1ec
--- /dev/null
+++ b/drivers/iio/adc/rzg2l_adc.c
@@ -0,0 +1,489 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RZ/G2L A/D Converter driver
+ *
+ * Copyright (c) 2021 Renesas Electronics Europe GmbH
+ *
+ * Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#define ADM(n) ((n) * 0x4)
+#define ADM0_ADCE BIT(0)
+#define ADM0_ADBSY BIT(1)
+#define ADM0_PWDWNB BIT(2)
+#define ADM0_SRESB BIT(15)
+#define ADM1_TRG BIT(0)
+#define ADM1_MS BIT(2)
+#define ADM1_BS BIT(4)
+#define ADM1_EGA_CLEAR ~GENMASK(13, 12)
+#define ADM2_CHSEL_CLEAR ~GENMASK(7, 0)
+#define ADM3_ADSMP 0x578
+#define ADM3_ADCMP (0xe << 16)
+#define ADM3_ADIL_CLEAR ~GENMASK(31, 24)
+
+#define ADINT 0x20
+#define ADINT_CH_CLEAR ~GENMASK(7, 0)
+#define ADINT_CSEEN BIT(16)
+#define ADINT_INTS BIT(31)
+#define ADSTS 0x24
+#define ADINT_INTST_MASK GENMASK(7, 0)
+#define ADSTS_CSEST BIT(16)
+#define ADIVC 0x28
+#define ADIVC_DIVADC_CLEAR ~GENMASK(8, 0)
+#define ADIVC_DIVADC_4 0x4
+#define ADFIL 0x2c
+#define ADCR(n) (0x30 + ((n) * 0x4))
+#define ADCR_AD_MASK GENMASK(11, 0)
+
+#define ADC_MAX_CHANNELS 8
+#define ADC_CHN_MASK 0x7
+#define ADC_TIMEOUT usecs_to_jiffies(1 * 4)
+
+enum trigger_mode {
+ SW_TRIGGER = 0,
+ SYNC_TRIGGER,
+ ASYNC_TRIGGER,
+};
+
+struct rzg2l_adc_data {
+ const struct iio_chan_spec *channels;
+ u8 num_channels;
+ u8 trigger;
+};
+
+struct rzg2l_adc {
+ void __iomem *base;
+ struct clk *pclk;
+ struct clk *adclk;
+ struct reset_control *presetn;
+ struct reset_control *adrstn;
+ struct completion completion;
+ const struct rzg2l_adc_data *data;
+ bool adc_disabled; /* protected with mlock mutex from indio_dev */
+ u16 last_val[ADC_MAX_CHANNELS];
+};
+
+static unsigned int rzg2l_adc_readl(struct rzg2l_adc *adc, u32 reg)
+{
+ return readl(adc->base + reg);
+}
+
+static void rzg2l_adc_writel(struct rzg2l_adc *adc, unsigned int reg, u32 val)
+{
+ writel(val, adc->base + reg);
+}
+
+static int rzg2l_adc_adclk(struct rzg2l_adc *adc, bool prepare)
+{
+ if (prepare)
+ return clk_prepare_enable(adc->adclk);
+
+ clk_disable_unprepare(adc->adclk);
+ return 0;
+}
+
+static void rzg2l_adc_pwr(struct rzg2l_adc *adc, bool on)
+{
+ u32 reg;
+
+ reg = rzg2l_adc_readl(adc, ADM(0));
+ if (on)
+ reg |= ADM0_PWDWNB;
+ else
+ reg &= ~ADM0_PWDWNB;
+ rzg2l_adc_writel(adc, ADM(0), reg);
+ udelay(2);
+}
+
+static void rzg2l_adc_conversion(struct rzg2l_adc *adc, bool start)
+{
+ int timeout = 5;
+ u32 reg;
+
+ /* stop A/D conversion */
+ reg = rzg2l_adc_readl(adc, ADM(0));
+ if (start)
+ reg |= ADM0_ADCE;
+ else
+ reg &= ~ADM0_ADCE;
+ rzg2l_adc_writel(adc, ADM(0), reg);
+
+ if (start)
+ return;
+
+ do {
+ usleep_range(100, 200);
+ reg = rzg2l_adc_readl(adc, ADM(0));
+ timeout--;
+ if (!timeout) {
+ pr_err("%s stopping ADC timed out\n", __func__);
+ break;
+ }
+ } while (((reg & ADM0_ADBSY) || (reg & ADM0_ADCE)));
+}
+
+static int rzg2l_adc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct rzg2l_adc *adc = iio_priv(indio_dev);
+ u32 reg;
+ int ret;
+ u8 ch;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&indio_dev->mlock);
+
+ if (adc->adc_disabled) {
+ mutex_unlock(&indio_dev->mlock);
+ return -EBUSY;
+ }
+
+ if (rzg2l_adc_readl(adc, ADM(0)) & ADM0_ADBSY) {
+ mutex_unlock(&indio_dev->mlock);
+ return -EBUSY;
+ }
+
+ ch = chan->channel & ADC_CHN_MASK;
+ /* SW trigger */
+ reg = rzg2l_adc_readl(adc, ADM(1));
+ reg &= ADM1_EGA_CLEAR;
+ reg &= ~ADM1_BS;
+ reg |= ADM1_MS;
+ reg &= ~ADM1_TRG;
+ rzg2l_adc_writel(adc, ADM(1), reg);
+
+ /* select channel */
+ reg = rzg2l_adc_readl(adc, ADM(2));
+ reg &= ADM2_CHSEL_CLEAR;
+ reg |= BIT(ch);
+ rzg2l_adc_writel(adc, ADM(2), reg);
+
+ reg = rzg2l_adc_readl(adc, ADM(3));
+ reg &= ADM3_ADIL_CLEAR;
+ reg |= ADM3_ADCMP;
+ reg |= ADM3_ADSMP;
+ rzg2l_adc_writel(adc, ADM(3), reg);
+
+ reg = rzg2l_adc_readl(adc, ADIVC);
+ reg &= ADIVC_DIVADC_CLEAR;
+ reg |= ADIVC_DIVADC_4;
+ rzg2l_adc_writel(adc, ADIVC, reg);
+
+ reg = rzg2l_adc_readl(adc, ADINT);
+ reg &= ~ADINT_INTS;
+ reg &= ADINT_CH_CLEAR;
+ reg |= ADINT_CSEEN;
+ reg |= BIT(ch);
+ rzg2l_adc_writel(adc, ADINT, reg);
+
+ rzg2l_adc_pwr(adc, true);
+
+ ret = rzg2l_adc_adclk(adc, true);
+ if (ret) {
+ rzg2l_adc_pwr(adc, false);
+ mutex_unlock(&indio_dev->mlock);
+ return -EINVAL;
+ }
+
+ reinit_completion(&adc->completion);
+
+ rzg2l_adc_conversion(adc, true);
+
+ if (!wait_for_completion_timeout(&adc->completion, ADC_TIMEOUT)) {
+ reg &= ADINT_CH_CLEAR;
+ rzg2l_adc_writel(adc, ADINT, reg);
+ rzg2l_adc_conversion(adc, false);
+ rzg2l_adc_adclk(adc, false);
+ rzg2l_adc_pwr(adc, false);
+ mutex_unlock(&indio_dev->mlock);
+ return -ETIMEDOUT;
+ }
+
+ *val = adc->last_val[ch];
+ rzg2l_adc_conversion(adc, false);
+ rzg2l_adc_adclk(adc, false);
+ rzg2l_adc_pwr(adc, false);
+ mutex_unlock(&indio_dev->mlock);
+ return IIO_VAL_INT;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static irqreturn_t rzg2l_adc_isr(int irq, void *dev_id)
+{
+ struct rzg2l_adc *adc = (struct rzg2l_adc *)dev_id;
+ u8 intst;
+ u32 reg;
+ u8 i;
+
+ reg = rzg2l_adc_readl(adc, ADSTS);
+ if (reg & ADSTS_CSEST) {
+ rzg2l_adc_writel(adc, ADSTS, reg);
+ return IRQ_HANDLED;
+ }
+
+ intst = reg & ADINT_INTST_MASK;
+ if (!intst)
+ return IRQ_HANDLED;
+
+ for (i = 0; i < ADC_MAX_CHANNELS; i++) {
+ if (intst & BIT(i))
+ adc->last_val[i] = rzg2l_adc_readl(adc, ADCR(i)) & ADCR_AD_MASK;
+ }
+
+ rzg2l_adc_writel(adc, ADSTS, reg);
+
+ complete(&adc->completion);
+
+ return IRQ_HANDLED;
+}
+
+static const struct iio_info rzg2l_adc_iio_info = {
+ .read_raw = rzg2l_adc_read_raw,
+};
+
+static const char * const rzg2l_adc_channel_name[] = {
+ "adc0",
+ "adc1",
+ "adc2",
+ "adc3",
+ "adc4",
+ "adc5",
+ "adc6",
+ "adc7",
+};
+
+static int rzg2l_adc_parse_of(struct platform_device *pdev, struct rzg2l_adc *adc)
+{
+ struct device_node *node = pdev->dev.of_node;
+ struct iio_chan_spec *chan_array;
+ u8 channels[ADC_MAX_CHANNELS];
+ struct rzg2l_adc_data *data;
+ int num_channels;
+ int ret;
+ u8 i;
+
+ data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ num_channels = of_property_count_u8_elems(node, "renesas-rzg2l,adc-channels");
+ if (num_channels <= 0 || num_channels > ADC_MAX_CHANNELS)
+ return -EINVAL;
+
+ ret = of_property_read_u8_array(node, "renesas-rzg2l,adc-channels",
+ channels, num_channels);
+ if (ret)
+ return ret;
+
+ chan_array = devm_kcalloc(&pdev->dev, num_channels, sizeof(*chan_array),
+ GFP_KERNEL);
+ if (!chan_array)
+ return -ENOMEM;
+
+ for (i = 0; i < num_channels; i++) {
+ chan_array[i].type = IIO_VOLTAGE;
+ chan_array[i].indexed = 1;
+ chan_array[i].channel = channels[i];
+ chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+ chan_array[i].info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
+ chan_array[i].datasheet_name = rzg2l_adc_channel_name[i];
+ }
+
+ ret = of_property_read_u8(node, "renesas-rzg2l,adc-trigger-mode",
+ &data->trigger);
+ if (ret)
+ data->trigger = SW_TRIGGER;
+
+ /* we support SW_TRIGGER as of now */
+ if (data->trigger != SW_TRIGGER)
+ return -EINVAL;
+
+ data->num_channels = num_channels;
+ data->channels = chan_array;
+ adc->data = data;
+
+ return 0;
+}
+
+static int rzg2l_adc_sw_reset(struct rzg2l_adc *adc)
+{
+ int timeout = 5;
+ u32 val;
+
+ val = rzg2l_adc_readl(adc, ADM(0));
+ val |= ADM0_SRESB;
+ rzg2l_adc_writel(adc, ADM(0), val);
+
+ while (!(rzg2l_adc_readl(adc, ADM(0)) & ADM0_SRESB)) {
+ if (!timeout)
+ return -EINVAL;
+ timeout--;
+ usleep_range(100, 200);
+ }
+
+ return 0;
+}
+
+static int rzg2l_adc_probe(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev;
+ struct rzg2l_adc *adc;
+ int ret;
+ int irq;
+
+ indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
+ if (!indio_dev) {
+ dev_err(&pdev->dev, "failed allocating iio device\n");
+ return -ENOMEM;
+ }
+
+ adc = iio_priv(indio_dev);
+ if (!adc)
+ return -ENOMEM;
+
+ ret = rzg2l_adc_parse_of(pdev, adc);
+ if (ret)
+ return -ENOMEM;
+
+ adc->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(adc->base)) {
+ dev_err(&pdev->dev, "missing mem resource");
+ return PTR_ERR(adc->base);
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "no irq resource\n");
+ return irq;
+ }
+
+ adc->pclk = devm_clk_get(&pdev->dev, "pclk");
+ if (IS_ERR(adc->pclk)) {
+ dev_err(&pdev->dev, "Failed to get pclk");
+ return PTR_ERR(adc->pclk);
+ }
+
+ adc->adclk = devm_clk_get(&pdev->dev, "adclk");
+ if (IS_ERR(adc->adclk)) {
+ dev_err(&pdev->dev, "Failed to get adclk");
+ return PTR_ERR(adc->adclk);
+ }
+
+ adc->adrstn = devm_reset_control_get_exclusive(&pdev->dev, "adrst-n");
+ if (IS_ERR(adc->adrstn)) {
+ dev_err(&pdev->dev, "failed to get adrstn\n");
+ return PTR_ERR(adc->adrstn);
+ }
+
+ adc->presetn = devm_reset_control_get_exclusive(&pdev->dev, "presetn");
+ if (IS_ERR(adc->presetn)) {
+ dev_err(&pdev->dev, "failed to get presetn\n");
+ return PTR_ERR(adc->presetn);
+ }
+
+ ret = reset_control_deassert(adc->adrstn);
+ if (ret)
+ return ret;
+
+ ret = reset_control_deassert(adc->presetn);
+ if (ret)
+ goto assert_adrstn;
+
+ ret = clk_prepare_enable(adc->pclk);
+ if (ret)
+ goto assert_presetn;
+
+ ret = rzg2l_adc_sw_reset(adc);
+ if (ret)
+ goto unprepare_pclk;
+
+ init_completion(&adc->completion);
+
+ platform_set_drvdata(pdev, indio_dev);
+
+ ret = devm_request_irq(&pdev->dev, irq, rzg2l_adc_isr,
+ 0, dev_name(&pdev->dev), adc);
+ if (ret < 0)
+ goto unprepare_pclk;
+
+ adc->adc_disabled = false;
+ indio_dev->name = dev_name(&pdev->dev);
+ indio_dev->dev.parent = &pdev->dev;
+ indio_dev->dev.of_node = pdev->dev.of_node;
+ indio_dev->info = &rzg2l_adc_iio_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = adc->data->channels;
+ indio_dev->num_channels = adc->data->num_channels;
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto unprepare_pclk;
+
+ return 0;
+
+unprepare_pclk:
+ clk_disable_unprepare(adc->pclk);
+assert_presetn:
+ reset_control_assert(adc->presetn);
+assert_adrstn:
+ reset_control_assert(adc->adrstn);
+ return ret;
+}
+
+static int rzg2l_adc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct rzg2l_adc *adc = iio_priv(indio_dev);
+
+ mutex_lock(&indio_dev->mlock);
+ adc->adc_disabled = true;
+ mutex_unlock(&indio_dev->mlock);
+
+ iio_device_unregister(indio_dev);
+
+ clk_disable_unprepare(adc->pclk);
+ reset_control_assert(adc->presetn);
+ reset_control_assert(adc->adrstn);
+
+ return 0;
+}
+
+static const struct of_device_id rzg2l_adc_match[] = {
+ {
+ .compatible = "renesas,rzg2l-adc",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, rzg2l_adc_match);
+
+static struct platform_driver rzg2l_adc_driver = {
+ .probe = rzg2l_adc_probe,
+ .remove = rzg2l_adc_remove,
+ .driver = {
+ .name = "rzg2l-adc",
+ .of_match_table = rzg2l_adc_match,
+ },
+};
+
+module_platform_driver(rzg2l_adc_driver);
+
+MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Renesas RZ/G2L ADC driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1