[PATCH] adc: add adc driver for Hisilicon BVT SOCs

* [PATCH] adc: add adc driver for Hisilicon BVT SOCs
@ 2016-12-24  1:54 Allen Liu
  2016-12-24  2:31 ` Jiancheng Xue
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Allen Liu @ 2016-12-24  1:54 UTC (permalink / raw)
  To: jic23, knaack.h, lars, pmeerw, robh+dt, mark.rutland
  Cc: akinobu.mita, ludovic.desroches, krzk, vilhelm.gray,
	ksenija.stanojevic, zhiyong.tao, daniel.baluta, leonard.crestez,
	ray.jui, raveendra.padasalagi, mranostay, amsfield22, linux-iio,
	devicetree, linux-kernel, xuejiancheng, kevin.lixu, liurenzhong

Add ADC driver for the ADC controller found on HiSilicon BVT SOCs, like Hi3516CV300, etc.
The ADC controller is primarily in charge of detecting voltage.

Reviewed-by: Jiancheng Xue <xuejiancheng@hisilicon.com>
Signed-off-by: Allen Liu <liurenzhong@hisilicon.com>
---
 .../devicetree/bindings/iio/adc/hibvt-lsadc.txt    |  26 ++
 drivers/iio/adc/Kconfig                            |  10 +
 drivers/iio/adc/Makefile                           |   1 +
 drivers/iio/adc/hibvt_lsadc.c                      | 344 +++++++++++++++++++++
 4 files changed, 381 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/hibvt-lsadc.txt
 create mode 100644 drivers/iio/adc/hibvt_lsadc.c

diff --git a/Documentation/devicetree/bindings/iio/adc/hibvt-lsadc.txt b/Documentation/devicetree/bindings/iio/adc/hibvt-lsadc.txt
new file mode 100644
index 0000000..63de46e
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/hibvt-lsadc.txt
@@ -0,0 +1,26 @@
+Hisilicon BVT Low Speed (LS) A/D Converter bindings
+
+Required properties:
+- compatible: should be "hisilicon,<name>-lsadc"
+   - "hisilicon,hibvt-lsadc": for hi3516cv300
+
+- reg: physical base address of the controller and length of memory mapped
+       region.
+- interrupts: The interrupt number to the cpu. The interrupt specifier format
+              depends on the interrupt controller.
+- #io-channel-cells: Should be 1, see ../iio-bindings.txt
+
+Optional properties:
+- resets: Must contain an entry for each entry in reset-names if need support
+	  this option. See ../reset/reset.txt for details.
+- reset-names: Must include the name "saradc-apb".
+
+Example:
+	lsadc: hibvt-lsadc@120e0000 {
+			compatible = "hisilicon,hibvt-lsadc";
+			reg = <0x120e0000 0x1000>;
+			interrupts = <19>;
+			resets = <&crg 0x7c 3>;
+			reset-names = "lsadc-crg";
+			status = "disabled";
+	};
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 99c0514..0443f51 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -225,6 +225,16 @@ config HI8435
 	  This driver can also be built as a module. If so, the module will be
 	  called hi8435.
 
+config HIBVT_LSADC
+	tristate "HIBVT LSADC driver"
+	depends on ARCH_HISI || COMPILE_TEST
+	help
+	  Say yes here to build support for the LSADC found in SoCs from
+	  hisilicon BVT chip.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called hibvt_lsadc.
+
 config INA2XX_ADC
 	tristate "Texas Instruments INA2xx Power Monitors IIO driver"
 	depends on I2C && !SENSORS_INA2XX
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 7a40c04..6554d92 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
 obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
 obj-$(CONFIG_FSL_MX25_ADC) += fsl-imx25-gcq.o
 obj-$(CONFIG_HI8435) += hi8435.o
+obj-$(CONFIG_HIBVT_LSADC) += hibvt_lsadc.o
 obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
 obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
diff --git a/drivers/iio/adc/hibvt_lsadc.c b/drivers/iio/adc/hibvt_lsadc.c
new file mode 100644
index 0000000..a20afe8
--- /dev/null
+++ b/drivers/iio/adc/hibvt_lsadc.c
@@ -0,0 +1,344 @@
+/*
+ * Hisilicon BVT Low Speed (LS) A/D Converter
+ * Copyright (C) 2016 HiSilicon Technologies Co., Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/reset.h>
+#include <linux/regulator/consumer.h>
+#include <linux/iio/iio.h>
+
+/* hisilicon bvt adc registers definitions */
+#define LSADC_CONFIG		0x00
+#define CONFIG_DEGLITCH		BIT(17)
+#define CONFIG_RESET		BIT(15)
+#define CONFIG_POWERDOWN	BIT(14)
+#define CONFIG_MODE			BIT(13)
+#define CONFIG_CHC_VALID	BIT(10)
+#define CONFIG_CHB_VALID	BIT(9)
+#define CONFIG_CHA_VALID	BIT(8)
+
+#define LSADC_TIMESCAN		0x08
+#define LSADC_INTEN			0x10
+#define LSADC_INTSTATUS		0x14
+#define LSADC_INTCLR		0x18
+#define LSADC_START			0x1C
+#define LSADC_STOP			0x20
+#define LSADC_ACTBIT		0x24
+#define LSADC_CHNDATA		0x2C
+
+#define ADC_CON_EN			(1u << 0)
+#define ADC_CON_DEN			(0u << 0)
+
+#define ADC_NUM_BITS		10
+
+/* fix clk:3000000, default tscan set 10ms */
+#define DEF_ADC_TSCAN_MS	(10*3000)
+
+#define LSADC_CHN_MASK		0x7
+
+#define LSADC_TIMEOUT		msecs_to_jiffies(100)
+
+/* default voltage scale for every channel <mv> */
+static int g_voltage[] = {
+	3300, 3300, 3300
+};
+
+struct hibvt_lsadc {
+	void __iomem		*regs;
+	struct completion	completion;
+	struct reset_control	*reset;
+	const struct hibvt_lsadc_data	*data;
+	unsigned int		cur_chn;
+	unsigned int		value;
+};
+
+struct hibvt_lsadc_data {
+	int				num_bits;
+	const struct iio_chan_spec	*channels;
+	int				num_channels;
+
+	void (*clear_irq)(struct hibvt_lsadc *info, int mask);
+	void (*start_conv)(struct hibvt_lsadc *info);
+	void (*stop_conv)(struct hibvt_lsadc *info);
+};
+
+static int hibvt_lsadc_read_raw(struct iio_dev *indio_dev,
+				    struct iio_chan_spec const *chan,
+				    int *val, int *val2, long mask)
+{
+	struct hibvt_lsadc *info = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&indio_dev->mlock);
+
+		reinit_completion(&info->completion);
+
+		/* Select the channel to be used */
+		info->cur_chn = chan->channel;
+
+		if (info->data->start_conv)
+			info->data->start_conv(info);
+
+		if (!wait_for_completion_timeout(&info->completion,
+							LSADC_TIMEOUT)) {
+			if (info->data->stop_conv)
+				info->data->stop_conv(info);
+			mutex_unlock(&indio_dev->mlock);
+			return -ETIMEDOUT;
+		}
+
+		*val = info->value;
+		mutex_unlock(&indio_dev->mlock);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = g_voltage[chan->channel];
+		*val2 = info->data->num_bits;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	default:
+		return -EINVAL;
+	}
+}
+
+static irqreturn_t hibvt_lsadc_isr(int irq, void *dev_id)
+{
+	struct hibvt_lsadc *info = (struct hibvt_lsadc *)dev_id;
+	int mask;
+
+	mask = readl(info->regs + LSADC_INTSTATUS);
+	mask &= LSADC_CHN_MASK;
+
+	/* Clear irq */
+	if (info->data->clear_irq)
+		info->data->clear_irq(info, mask);
+
+	/* Read value */
+	info->value = readl(info->regs + LSADC_CHNDATA + (info->cur_chn << 2));
+	info->value &= GENMASK(info->data->num_bits - 1, 0);
+
+	/* stop adc */
+	if (info->data->stop_conv)
+		info->data->stop_conv(info);
+
+	complete(&info->completion);
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_info hibvt_lsadc_iio_info = {
+	.read_raw = hibvt_lsadc_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+#define ADC_CHANNEL(_index, _id) {      \
+	.type = IIO_VOLTAGE,                \
+	.indexed = 1,						\
+	.channel = _index,					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
+			BIT(IIO_CHAN_INFO_SCALE),   \
+	.datasheet_name = _id,              \
+}
+
+static const struct iio_chan_spec hibvt_lsadc_iio_channels[] = {
+	ADC_CHANNEL(0, "adc0"),
+	ADC_CHANNEL(1, "adc1"),
+	ADC_CHANNEL(2, "adc2"),
+};
+
+static void hibvt_lsadc_clear_irq(struct hibvt_lsadc *info, int mask)
+{
+	writel(mask, info->regs + LSADC_INTCLR);
+}
+
+static void hibvt_lsadc_start_conv(struct hibvt_lsadc *info)
+{
+	unsigned int con;
+
+	/* set number bit */
+	con = GENMASK(info->data->num_bits - 1, 0);
+	writel(con, (info->regs + LSADC_ACTBIT));
+
+    /* config */
+	con = readl(info->regs + LSADC_CONFIG);
+	con &= ~CONFIG_RESET;
+	con |= (CONFIG_POWERDOWN | CONFIG_DEGLITCH | CONFIG_MODE);
+	con &= ~(CONFIG_CHA_VALID | CONFIG_CHB_VALID | CONFIG_CHC_VALID);
+	con |= (CONFIG_CHA_VALID << info->cur_chn);
+	writel(con, (info->regs + LSADC_CONFIG));
+
+	/* set timescan */
+	writel(DEF_ADC_TSCAN_MS, (info->regs + LSADC_TIMESCAN));
+
+	/* clear interrupt */
+	writel(LSADC_CHN_MASK, info->regs + LSADC_INTCLR);
+
+	/* enable interrupt */
+	writel(ADC_CON_EN, (info->regs + LSADC_INTEN));
+
+	/* start scan */
+	writel(ADC_CON_EN, (info->regs + LSADC_START));
+}
+
+static void hibvt_lsadc_stop_conv(struct hibvt_lsadc *info)
+{
+	/* reset the timescan */
+	writel(ADC_CON_DEN, (info->regs + LSADC_TIMESCAN));
+
+	/* disable interrupt */
+	writel(ADC_CON_DEN, (info->regs + LSADC_INTEN));
+
+	/* stop scan */
+	writel(ADC_CON_EN, (info->regs + LSADC_STOP));
+}
+
+static const struct hibvt_lsadc_data lsadc_data = {
+	.num_bits = ADC_NUM_BITS,
+	.channels = hibvt_lsadc_iio_channels,
+	.num_channels = ARRAY_SIZE(hibvt_lsadc_iio_channels),
+
+	.clear_irq	= hibvt_lsadc_clear_irq,
+	.start_conv	= hibvt_lsadc_start_conv,
+	.stop_conv = hibvt_lsadc_stop_conv,
+};
+
+static const struct of_device_id hibvt_lsadc_match[] = {
+	{
+		.compatible = "hisilicon,hibvt-lsadc",
+		.data = &lsadc_data,
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, hibvt_lsadc_match);
+
+/**
+ * Reset LSADC Controller.
+ */
+static void hibvt_lsadc_reset_controller(struct reset_control *reset)
+{
+	reset_control_assert(reset);
+	usleep_range(10, 20);
+	reset_control_deassert(reset);
+}
+
+static int hibvt_lsadc_probe(struct platform_device *pdev)
+{
+	struct hibvt_lsadc *info = NULL;
+	struct device_node *np = pdev->dev.of_node;
+	struct iio_dev *indio_dev = NULL;
+	struct resource	*mem;
+	const struct of_device_id *match;
+	int ret;
+	int irq;
+
+	if (!np)
+		return -ENODEV;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
+	if (!indio_dev) {
+		dev_err(&pdev->dev, "failed allocating iio device\n");
+		return -ENOMEM;
+	}
+	info = iio_priv(indio_dev);
+
+	match = of_match_device(hibvt_lsadc_match, &pdev->dev);
+	info->data = match->data;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	info->regs = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(info->regs))
+		return PTR_ERR(info->regs);
+
+	/*
+	 * The reset should be an optional property, as it should work
+	 * with old devicetrees as well
+	 */
+	info->reset = devm_reset_control_get(&pdev->dev, "lsadc-crg");
+	if (IS_ERR(info->reset)) {
+		ret = PTR_ERR(info->reset);
+		if (ret != -ENOENT)
+			return ret;
+
+		dev_dbg(&pdev->dev, "no reset control found\n");
+		info->reset = NULL;
+	}
+
+	init_completion(&info->completion);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "no irq resource?\n");
+		return irq;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq, hibvt_lsadc_isr,
+			       0, dev_name(&pdev->dev), info);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed requesting irq %d\n", irq);
+		return ret;
+	}
+
+	if (info->reset)
+		hibvt_lsadc_reset_controller(info->reset);
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	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 = &hibvt_lsadc_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	indio_dev->channels = info->data->channels;
+	indio_dev->num_channels = info->data->num_channels;
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed register iio device\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int hibvt_lsadc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+
+	iio_device_unregister(indio_dev);
+
+	return 0;
+}
+
+static struct platform_driver hibvt_lsadc_driver = {
+	.probe		= hibvt_lsadc_probe,
+	.remove		= hibvt_lsadc_remove,
+	.driver		= {
+		.name	= "hibvt-lsadc",
+		.of_match_table = hibvt_lsadc_match,
+	},
+};
+
+module_platform_driver(hibvt_lsadc_driver);
+
+MODULE_AUTHOR("Allen Liu <liurenzhong@hisilicon.com>");
+MODULE_DESCRIPTION("hisilicon BVT LSADC driver");
+MODULE_LICENSE("GPL v2");
-- 
2.1.4

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