[PATCH 0/4] Support for analog peripherals on LPC18xx familiy

[PATCH 0/4] Support for analog peripherals on LPC18xx familiy

[Joachim Eastwood]

This patch set adds support for the analog (ADC and DAC) peripherals
found on NXP LPC18xx/43xx SoCs. The ADC is a SAR converter with 10-bit
resolution and 8 muxed inputs. The DAC is a simple single channel 10-
bit DAC.

Note that these drivers do not support all the features found on the
peripherals. DMA and interrupts are not supported in either drivers.
The ADC driver also lack 'burst-mode' and hardware triggers. So for
now the ADC is limited to single shot samples.

Both drivers tested on Embedded Artists' LPC4357 Developer's Kit.

Based on iio/testing branch from 29.02.15.


Joachim Eastwood (4):
  iio: adc: add NXP LPC18xx ADC driver
  dt: document NXP LPC1850 ADC driver bindings
  iio: dac: add NXP LPC18xx DAC driver
  dt: document NXP LPC1850 DAC driver bindings

 .../devicetree/bindings/iio/adc/lpc1850-adc.txt    |  21 ++
 .../devicetree/bindings/iio/dac/lpc1850-dac.txt    |  20 ++
 drivers/iio/adc/Kconfig                            |  10 +
 drivers/iio/adc/Makefile                           |   1 +
 drivers/iio/adc/lpc18xx_adc.c                      | 226 +++++++++++++++++++++
 drivers/iio/dac/Kconfig                            |  10 +
 drivers/iio/dac/Makefile                           |   1 +
 drivers/iio/dac/lpc18xx_dac.c                      | 204 +++++++++++++++++++
 8 files changed, 493 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/lpc1850-adc.txt
 create mode 100644 Documentation/devicetree/bindings/iio/dac/lpc1850-dac.txt
 create mode 100644 drivers/iio/adc/lpc18xx_adc.c
 create mode 100644 drivers/iio/dac/lpc18xx_dac.c

-- 
1.8.0

[PATCH 1/4] iio: adc: add NXP LPC18xx ADC driver

[Joachim Eastwood]

Add base support for the 10-bit SAR ADC peripheral found
on NXP LPC18xx/43xx SoCs.

This is a minimal driver that does not support burst mode,
interrupts, DMA or hardware triggers.

User manual with register description can be found on:
LPC18xx: www.nxp.com/documents/user_manual/UM10430.pdf
LPC43xx: www.nxp.com/documents/user_manual/UM10503.pdf

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
---
 drivers/iio/adc/Kconfig       |  10 ++
 drivers/iio/adc/Makefile      |   1 +
 drivers/iio/adc/lpc18xx_adc.c | 226 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 237 insertions(+)
 create mode 100644 drivers/iio/adc/lpc18xx_adc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 932de1f9d1e7..85994e5889ec 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -234,6 +234,16 @@ config LP8788_ADC
 	  To compile this driver as a module, choose M here: the module will be
 	  called lp8788_adc.
 
+config LPC18XX_ADC
+	tristate "NXP LPC18xx ADC driver"
+	depends on ARCH_LPC18XX || COMPILE_TEST
+	depends on OF && HAS_IOMEM
+	help
+	  Say yes here to build support for NXP LPC18XX ADC.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called lpc18xx_adc.
+
 config MAX1027
 	tristate "Maxim max1027 ADC driver"
 	depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index b1aa456e6af3..1a4ac4590857 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_HI8435) += hi8435.o
 obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
 obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
+obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
 obj-$(CONFIG_MAX1027) += max1027.o
 obj-$(CONFIG_MAX1363) += max1363.o
 obj-$(CONFIG_MCP320X) += mcp320x.o
diff --git a/drivers/iio/adc/lpc18xx_adc.c b/drivers/iio/adc/lpc18xx_adc.c
new file mode 100644
index 000000000000..f78bd8ddbff3
--- /dev/null
+++ b/drivers/iio/adc/lpc18xx_adc.c
@@ -0,0 +1,226 @@
+/*
+ * IIO ADC driver for NXP LPC18xx ADC
+ *
+ * Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * UNSUPPORTED hardware features:
+ *  - Hardware triggers
+ *  - Burst mode
+ *  - Interrupts
+ *  - DMA
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+/* LPC18XX ADC registers and bits */
+#define LPC18XX_ADC_CR			0x000
+#define  LPC18XX_ADC_CR_CLKDIV_SHIFT	8
+#define  LPC18XX_ADC_CR_PDN		BIT(21)
+#define  LPC18XX_ADC_CR_START_NOW	(0x1 << 24)
+#define LPC18XX_ADC_GDR			0x004
+
+/* Data registers bits */
+#define LPC18XX_ADC_SAMPLE_SHIFT	6
+#define LPC18XX_ADC_SAMPLE_MASK		0x3ff
+#define LPC18XX_ADC_CONV_DONE		BIT(31)
+
+/* Clock should be 4.5 MHz or less */
+#define LPC18XX_ADC_CLK_TARGET		4500000
+
+struct lpc18xx_adc {
+	void __iomem *base;
+	struct device *dev;
+	struct clk *clk;
+	struct regulator *vref;
+	u32 cr_reg;
+};
+
+#define LPC18XX_ADC_CHAN(_idx) {				\
+	.type = IIO_VOLTAGE,					\
+	.indexed = 1,						\
+	.channel = _idx,					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+}
+
+static const struct iio_chan_spec lpc18xx_adc_iio_channels[] = {
+	LPC18XX_ADC_CHAN(0),
+	LPC18XX_ADC_CHAN(1),
+	LPC18XX_ADC_CHAN(2),
+	LPC18XX_ADC_CHAN(3),
+	LPC18XX_ADC_CHAN(4),
+	LPC18XX_ADC_CHAN(5),
+	LPC18XX_ADC_CHAN(6),
+	LPC18XX_ADC_CHAN(7),
+};
+
+static int lpc18xx_adc_read_chan(struct lpc18xx_adc *adc, unsigned int ch)
+{
+	int ret;
+	u32 reg;
+
+	reg = adc->cr_reg | BIT(ch) | LPC18XX_ADC_CR_START_NOW;
+	writel(reg, adc->base + LPC18XX_ADC_CR);
+
+	ret = readl_poll_timeout(adc->base + LPC18XX_ADC_GDR, reg,
+				 reg & LPC18XX_ADC_CONV_DONE, 3, 9);
+	if (ret) {
+		dev_warn(adc->dev, "adc read timed out\n");
+		return ret;
+	}
+
+	return (reg >> LPC18XX_ADC_SAMPLE_SHIFT) & LPC18XX_ADC_SAMPLE_MASK;
+}
+
+static int lpc18xx_adc_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	struct lpc18xx_adc *adc = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		*val = lpc18xx_adc_read_chan(adc, chan->channel);
+		if (*val < 0)
+			return *val;
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		*val = regulator_get_voltage(adc->vref) / 1000;
+		*val2 = 10;
+
+		return IIO_VAL_FRACTIONAL_LOG2;
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info lpc18xx_adc_info = {
+	.read_raw = lpc18xx_adc_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int lpc18xx_adc_probe(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev;
+	struct lpc18xx_adc *adc;
+	struct resource *res;
+	unsigned int clkdiv;
+	unsigned long rate;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, indio_dev);
+	adc = iio_priv(indio_dev);
+	adc->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	adc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(adc->base))
+		return PTR_ERR(adc->base);
+
+	adc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(adc->clk)) {
+		dev_err(&pdev->dev, "error getting clock\n");
+		return PTR_ERR(adc->clk);
+	}
+
+	rate = clk_get_rate(adc->clk);
+	clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
+
+	adc->vref = devm_regulator_get(&pdev->dev, "vref");
+	if (IS_ERR(adc->vref)) {
+		dev_err(&pdev->dev, "error get regulator\n");
+		return PTR_ERR(adc->vref);
+	}
+
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->info = &lpc18xx_adc_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = lpc18xx_adc_iio_channels;
+	indio_dev->num_channels = ARRAY_SIZE(lpc18xx_adc_iio_channels);
+
+	ret = regulator_enable(adc->vref);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable regulator\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(adc->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable clock.\n");
+		goto dis_reg;
+	}
+
+	adc->cr_reg = (clkdiv << LPC18XX_ADC_CR_CLKDIV_SHIFT) |
+			LPC18XX_ADC_CR_PDN;
+	writel(adc->cr_reg, adc->base + LPC18XX_ADC_CR);
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to register device\n");
+		goto dis_clk;
+	}
+
+	return 0;
+
+dis_clk:
+	writel(0, adc->base + LPC18XX_ADC_CR);
+	clk_disable_unprepare(adc->clk);
+dis_reg:
+	regulator_disable(adc->vref);
+	return ret;
+}
+
+static int lpc18xx_adc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct lpc18xx_adc *adc = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	writel(0, adc->base + LPC18XX_ADC_CR);
+	clk_disable_unprepare(adc->clk);
+	regulator_disable(adc->vref);
+
+	return 0;
+}
+
+static const struct of_device_id lpc18xx_adc_match[] = {
+	{ .compatible = "nxp,lpc1850-adc" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, lpc18xx_adc_match);
+
+static struct platform_driver lpc18xx_adc_driver = {
+	.probe	= lpc18xx_adc_probe,
+	.remove	= lpc18xx_adc_remove,
+	.driver	= {
+		.name = "lpc18xx-adc",
+		.of_match_table = lpc18xx_adc_match,
+	},
+};
+module_platform_driver(lpc18xx_adc_driver);
+
+MODULE_DESCRIPTION("LPC18xx ADC driver");
+MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
+MODULE_LICENSE("GPL v2");
-- 
1.8.0

[PATCH 2/4] dt: document NXP LPC1850 ADC driver bindings

[Joachim Eastwood]

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
---
 .../devicetree/bindings/iio/adc/lpc1850-adc.txt     | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/lpc1850-adc.txt

diff --git a/Documentation/devicetree/bindings/iio/adc/lpc1850-adc.txt b/Documentation/devicetree/bindings/iio/adc/lpc1850-adc.txt
new file mode 100644
index 000000000000..0bcae5140bc5
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/lpc1850-adc.txt
@@ -0,0 +1,21 @@
+NXP LPC1850 ADC bindings
+
+Required properties:
+- compatible: Should be "nxp,lpc1850-adc"
+- reg: Offset and length of the register set for the ADC device
+- interrupts: The interrupt number for the ADC device
+- clocks: The root clock of the ADC controller
+- vref-supply: The regulator supply ADC reference voltage
+- resets: phandle to reset controller and line specifier
+
+Example:
+
+adc0: adc@400e3000 {
+	compatible = "nxp,lpc1850-adc";
+	reg = <0x400e3000 0x1000>;
+	interrupts = <17>;
+	clocks = <&ccu1 CLK_APB3_ADC0>;
+	vref-supply = <&reg_vdda>;
+	resets = <&rgu 40>;
+	status = "disabled";
+};
-- 
1.8.0

[PATCH 3/4] iio: dac: add NXP LPC18xx DAC driver

[Joachim Eastwood]

Add base support for the 10-bit DAC peripheral found
on NXP LPC18xx/43xx SoCs.

This is a minimal driver that does not support DMA or
interrupts.

User manual with register description can be found on:
LPC18xx: www.nxp.com/documents/user_manual/UM10430.pdf
LPC43xx: www.nxp.com/documents/user_manual/UM10503.pdf

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
---
 drivers/iio/dac/Kconfig       |  10 +++
 drivers/iio/dac/Makefile      |   1 +
 drivers/iio/dac/lpc18xx_dac.c | 204 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 215 insertions(+)
 create mode 100644 drivers/iio/dac/lpc18xx_dac.c

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index a995139f907c..210db81ca144 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -154,6 +154,16 @@ config AD7303
 	  To compile this driver as module choose M here: the module will be called
 	  ad7303.
 
+config LPC18XX_DAC
+	tristate "NXP LPC18xx DAC driver"
+	depends on ARCH_LPC18XX || COMPILE_TEST
+	depends on OF && HAS_IOMEM
+	help
+	  Say yes here to build support for NXP LPC18XX DAC.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called lpc18xx_dac.
+
 config M62332
 	tristate "Mitsubishi M62332 DAC driver"
 	depends on I2C
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 67b48429686d..420a15cdaa53 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_AD5764) += ad5764.o
 obj-$(CONFIG_AD5791) += ad5791.o
 obj-$(CONFIG_AD5686) += ad5686.o
 obj-$(CONFIG_AD7303) += ad7303.o
+obj-$(CONFIG_LPC18XX_DAC) += lpc18xx_dac.o
 obj-$(CONFIG_M62332) += m62332.o
 obj-$(CONFIG_MAX517) += max517.o
 obj-$(CONFIG_MAX5821) += max5821.o
diff --git a/drivers/iio/dac/lpc18xx_dac.c b/drivers/iio/dac/lpc18xx_dac.c
new file mode 100644
index 000000000000..5f4668be603f
--- /dev/null
+++ b/drivers/iio/dac/lpc18xx_dac.c
@@ -0,0 +1,204 @@
+/*
+ * IIO DAC driver for NXP LPC18xx DAC
+ *
+ * Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * UNSUPPORTED hardware features:
+ *  - Interrupts
+ *  - DMA
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+/* LPC18XX DAC registers and bits */
+#define LPC18XX_DAC_CR			0x000
+#define  LPC18XX_DAC_CR_VALUE_SHIFT	6
+#define  LPC18XX_DAC_CR_VALUE_MASK	0x3ff
+#define  LPC18XX_DAC_CR_BIAS		BIT(16)
+#define LPC18XX_DAC_CTRL		0x004
+#define  LPC18XX_DAC_CTRL_DMA_ENA	BIT(3)
+
+struct lpc18xx_dac {
+	struct clk *clk;
+	void __iomem *base;
+	struct regulator *vref;
+};
+
+static const struct iio_chan_spec lpc18xx_dac_iio_channels[] = {
+	{
+		.type = IIO_VOLTAGE,
+		.output = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+	},
+};
+
+static int lpc18xx_dac_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	struct lpc18xx_dac *dac = iio_priv(indio_dev);
+	u32 reg;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		reg = readl(dac->base + LPC18XX_DAC_CR);
+		*val = reg >> LPC18XX_DAC_CR_VALUE_SHIFT;
+		*val &= LPC18XX_DAC_CR_VALUE_MASK;
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		*val = regulator_get_voltage(dac->vref) / 1000;
+		*val2 = 10;
+
+		return IIO_VAL_FRACTIONAL_LOG2;
+	}
+
+	return -EINVAL;
+}
+
+static int lpc18xx_dac_write_raw(struct iio_dev *indio_dev,
+				 struct iio_chan_spec const *chan,
+				 int val, int val2, long mask)
+{
+	struct lpc18xx_dac *dac = iio_priv(indio_dev);
+	u32 reg;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (val < 0 || val > LPC18XX_DAC_CR_VALUE_MASK)
+			return -EINVAL;
+
+		reg = LPC18XX_DAC_CR_BIAS;
+		reg |= val << LPC18XX_DAC_CR_VALUE_SHIFT;
+		writel(reg, dac->base + LPC18XX_DAC_CR);
+		writel(LPC18XX_DAC_CTRL_DMA_ENA, dac->base + LPC18XX_DAC_CTRL);
+
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info lpc18xx_dac_info = {
+	.read_raw = lpc18xx_dac_read_raw,
+	.write_raw = lpc18xx_dac_write_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int lpc18xx_dac_probe(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev;
+	struct lpc18xx_dac *dac;
+	struct resource *res;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, indio_dev);
+	dac = iio_priv(indio_dev);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dac->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dac->base))
+		return PTR_ERR(dac->base);
+
+	dac->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dac->clk)) {
+		dev_err(&pdev->dev, "error getting clock\n");
+		return PTR_ERR(dac->clk);
+	}
+
+	dac->vref = devm_regulator_get(&pdev->dev, "vref");
+	if (IS_ERR(dac->vref)) {
+		dev_err(&pdev->dev, "error get regulator\n");
+		return PTR_ERR(dac->vref);
+	}
+
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->info = &lpc18xx_dac_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = lpc18xx_dac_iio_channels;
+	indio_dev->num_channels = ARRAY_SIZE(lpc18xx_dac_iio_channels);
+
+	ret = regulator_enable(dac->vref);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable regulator\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(dac->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable clock.\n");
+		goto dis_reg;
+	}
+
+	writel(0, dac->base + LPC18XX_DAC_CTRL);
+	writel(0, dac->base + LPC18XX_DAC_CR);
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to register device\n");
+		goto dis_clk;
+	}
+
+	return 0;
+
+dis_clk:
+	clk_disable_unprepare(dac->clk);
+dis_reg:
+	regulator_disable(dac->vref);
+	return ret;
+}
+
+static int lpc18xx_dac_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct lpc18xx_dac *dac = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	writel(0, dac->base + LPC18XX_DAC_CTRL);
+	clk_disable_unprepare(dac->clk);
+	regulator_disable(dac->vref);
+
+	return 0;
+}
+
+static const struct of_device_id lpc18xx_dac_match[] = {
+	{ .compatible = "nxp,lpc1850-dac" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, lpc18xx_dac_match);
+
+static struct platform_driver lpc18xx_dac_driver = {
+	.probe	= lpc18xx_dac_probe,
+	.remove	= lpc18xx_dac_remove,
+	.driver	= {
+		.name = "lpc18xx-dac",
+		.of_match_table = lpc18xx_dac_match,
+	},
+};
+module_platform_driver(lpc18xx_dac_driver);
+
+MODULE_DESCRIPTION("LPC18xx DAC driver");
+MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
+MODULE_LICENSE("GPL v2");
-- 
1.8.0

[PATCH 4/4] dt: document NXP LPC1850 DAC driver bindings

[Joachim Eastwood]

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
---
 .../devicetree/bindings/iio/dac/lpc1850-dac.txt      | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/dac/lpc1850-dac.txt

diff --git a/Documentation/devicetree/bindings/iio/dac/lpc1850-dac.txt b/Documentation/devicetree/bindings/iio/dac/lpc1850-dac.txt
new file mode 100644
index 000000000000..7d6647d4af5e
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/dac/lpc1850-dac.txt
@@ -0,0 +1,20 @@
+NXP LPC1850 DAC bindings
+
+Required properties:
+- compatible: Should be "nxp,lpc1850-dac"
+- reg: Offset and length of the register set for the ADC device
+- interrupts: The interrupt number for the ADC device
+- clocks: The root clock of the ADC controller
+- vref-supply: The regulator supply ADC reference voltage
+- resets: phandle to reset controller and line specifier
+
+Example:
+dac: dac@400e1000 {
+	compatible = "nxp,lpc1850-dac";
+	reg = <0x400e1000 0x1000>;
+	interrupts = <0>;
+	clocks = <&ccu1 CLK_APB3_DAC>;
+	vref-supply = <&reg_vdda>;
+	resets = <&rgu 42>;
+	status = "disabled";
+};
-- 
1.8.0

Re: [PATCH 1/4] iio: adc: add NXP LPC18xx ADC driver

[Peter Meerwald-Stadler]

> Add base support for the 10-bit SAR ADC peripheral found
> on NXP LPC18xx/43xx SoCs.

nitpicking below
 
> This is a minimal driver that does not support burst mode,
> interrupts, DMA or hardware triggers.
> 
> User manual with register description can be found on:
> LPC18xx: www.nxp.com/documents/user_manual/UM10430.pdf
> LPC43xx: www.nxp.com/documents/user_manual/UM10503.pdf
> 
> Signed-off-by: Joachim Eastwood <manabian@gmail.com>
> ---
>  drivers/iio/adc/Kconfig       |  10 ++
>  drivers/iio/adc/Makefile      |   1 +
>  drivers/iio/adc/lpc18xx_adc.c | 226 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 237 insertions(+)
>  create mode 100644 drivers/iio/adc/lpc18xx_adc.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 932de1f9d1e7..85994e5889ec 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -234,6 +234,16 @@ config LP8788_ADC
>  	  To compile this driver as a module, choose M here: the module will be
>  	  called lp8788_adc.
>  
> +config LPC18XX_ADC
> +	tristate "NXP LPC18xx ADC driver"
> +	depends on ARCH_LPC18XX || COMPILE_TEST
> +	depends on OF && HAS_IOMEM
> +	help
> +	  Say yes here to build support for NXP LPC18XX ADC.
> +
> +	  To compile this driver as a module, choose M here: the module will be
> +	  called lpc18xx_adc.
> +
>  config MAX1027
>  	tristate "Maxim max1027 ADC driver"
>  	depends on SPI
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index b1aa456e6af3..1a4ac4590857 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_HI8435) += hi8435.o
>  obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
>  obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> +obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
>  obj-$(CONFIG_MAX1027) += max1027.o
>  obj-$(CONFIG_MAX1363) += max1363.o
>  obj-$(CONFIG_MCP320X) += mcp320x.o
> diff --git a/drivers/iio/adc/lpc18xx_adc.c b/drivers/iio/adc/lpc18xx_adc.c
> new file mode 100644
> index 000000000000..f78bd8ddbff3
> --- /dev/null
> +++ b/drivers/iio/adc/lpc18xx_adc.c
> @@ -0,0 +1,226 @@
> +/*
> + * IIO ADC driver for NXP LPC18xx ADC
> + *
> + * Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * UNSUPPORTED hardware features:
> + *  - Hardware triggers
> + *  - Burst mode
> + *  - Interrupts
> + *  - DMA
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/driver.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> +
> +/* LPC18XX ADC registers and bits */
> +#define LPC18XX_ADC_CR			0x000
> +#define  LPC18XX_ADC_CR_CLKDIV_SHIFT	8
> +#define  LPC18XX_ADC_CR_PDN		BIT(21)
> +#define  LPC18XX_ADC_CR_START_NOW	(0x1 << 24)
> +#define LPC18XX_ADC_GDR			0x004
> +
> +/* Data registers bits */

'Data register bits' maybe

> +#define LPC18XX_ADC_SAMPLE_SHIFT	6
> +#define LPC18XX_ADC_SAMPLE_MASK		0x3ff
> +#define LPC18XX_ADC_CONV_DONE		BIT(31)
> +
> +/* Clock should be 4.5 MHz or less */
> +#define LPC18XX_ADC_CLK_TARGET		4500000
> +
> +struct lpc18xx_adc {
> +	void __iomem *base;
> +	struct device *dev;
> +	struct clk *clk;
> +	struct regulator *vref;
> +	u32 cr_reg;
> +};
> +
> +#define LPC18XX_ADC_CHAN(_idx) {				\
> +	.type = IIO_VOLTAGE,					\
> +	.indexed = 1,						\
> +	.channel = _idx,					\
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
> +}
> +
> +static const struct iio_chan_spec lpc18xx_adc_iio_channels[] = {
> +	LPC18XX_ADC_CHAN(0),
> +	LPC18XX_ADC_CHAN(1),
> +	LPC18XX_ADC_CHAN(2),
> +	LPC18XX_ADC_CHAN(3),
> +	LPC18XX_ADC_CHAN(4),
> +	LPC18XX_ADC_CHAN(5),
> +	LPC18XX_ADC_CHAN(6),
> +	LPC18XX_ADC_CHAN(7),
> +};
> +
> +static int lpc18xx_adc_read_chan(struct lpc18xx_adc *adc, unsigned int ch)
> +{
> +	int ret;
> +	u32 reg;
> +
> +	reg = adc->cr_reg | BIT(ch) | LPC18XX_ADC_CR_START_NOW;
> +	writel(reg, adc->base + LPC18XX_ADC_CR);
> +
> +	ret = readl_poll_timeout(adc->base + LPC18XX_ADC_GDR, reg,
> +				 reg & LPC18XX_ADC_CONV_DONE, 3, 9);
> +	if (ret) {
> +		dev_warn(adc->dev, "adc read timed out\n");
> +		return ret;
> +	}
> +
> +	return (reg >> LPC18XX_ADC_SAMPLE_SHIFT) & LPC18XX_ADC_SAMPLE_MASK;
> +}
> +
> +static int lpc18xx_adc_read_raw(struct iio_dev *indio_dev,
> +				struct iio_chan_spec const *chan,
> +				int *val, int *val2, long mask)
> +{
> +	struct lpc18xx_adc *adc = iio_priv(indio_dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		*val = lpc18xx_adc_read_chan(adc, chan->channel);
> +		if (*val < 0)
> +			return *val;
> +
> +		return IIO_VAL_INT;
> +
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = regulator_get_voltage(adc->vref) / 1000;
> +		*val2 = 10;
> +
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static const struct iio_info lpc18xx_adc_info = {
> +	.read_raw = lpc18xx_adc_read_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +static int lpc18xx_adc_probe(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev;
> +	struct lpc18xx_adc *adc;
> +	struct resource *res;
> +	unsigned int clkdiv;
> +	unsigned long rate;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, indio_dev);
> +	adc = iio_priv(indio_dev);
> +	adc->dev = &pdev->dev;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	adc->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(adc->base))
> +		return PTR_ERR(adc->base);
> +
> +	adc->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(adc->clk)) {
> +		dev_err(&pdev->dev, "error getting clock\n");
> +		return PTR_ERR(adc->clk);
> +	}
> +
> +	rate = clk_get_rate(adc->clk);
> +	clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
> +
> +	adc->vref = devm_regulator_get(&pdev->dev, "vref");
> +	if (IS_ERR(adc->vref)) {
> +		dev_err(&pdev->dev, "error get regulator\n");

getting

> +		return PTR_ERR(adc->vref);
> +	}
> +
> +	indio_dev->name = dev_name(&pdev->dev);
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->info = &lpc18xx_adc_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = lpc18xx_adc_iio_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(lpc18xx_adc_iio_channels);
> +
> +	ret = regulator_enable(adc->vref);
> +	if (ret) {
> +		dev_err(&pdev->dev, "unable to enable regulator\n");
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(adc->clk);
> +	if (ret) {
> +		dev_err(&pdev->dev, "unable to enable clock.\n");

maybe delete '.', it's the only message with a full stop

> +		goto dis_reg;
> +	}
> +
> +	adc->cr_reg = (clkdiv << LPC18XX_ADC_CR_CLKDIV_SHIFT) |
> +			LPC18XX_ADC_CR_PDN;
> +	writel(adc->cr_reg, adc->base + LPC18XX_ADC_CR);
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "unable to register device\n");
> +		goto dis_clk;
> +	}
> +
> +	return 0;
> +
> +dis_clk:
> +	writel(0, adc->base + LPC18XX_ADC_CR);
> +	clk_disable_unprepare(adc->clk);
> +dis_reg:
> +	regulator_disable(adc->vref);
> +	return ret;
> +}
> +
> +static int lpc18xx_adc_remove(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +	struct lpc18xx_adc *adc = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +
> +	writel(0, adc->base + LPC18XX_ADC_CR);
> +	clk_disable_unprepare(adc->clk);
> +	regulator_disable(adc->vref);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id lpc18xx_adc_match[] = {
> +	{ .compatible = "nxp,lpc1850-adc" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, lpc18xx_adc_match);
> +
> +static struct platform_driver lpc18xx_adc_driver = {
> +	.probe	= lpc18xx_adc_probe,
> +	.remove	= lpc18xx_adc_remove,
> +	.driver	= {
> +		.name = "lpc18xx-adc",
> +		.of_match_table = lpc18xx_adc_match,
> +	},
> +};
> +module_platform_driver(lpc18xx_adc_driver);
> +
> +MODULE_DESCRIPTION("LPC18xx ADC driver");
> +MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
> +MODULE_LICENSE("GPL v2");
> 

-- 

Peter Meerwald-Stadler
+43-664-2444418 (mobile)

Re: [PATCH 1/4] iio: adc: add NXP LPC18xx ADC driver

[Joachim Eastwood]

Hi Peter,

On 29 February 2016 at 20:42, Peter Meerwald-Stadler <pmeerw@pmeerw.net> wrote:
>
>> Add base support for the 10-bit SAR ADC peripheral found
>> on NXP LPC18xx/43xx SoCs.
>
> nitpicking below
>
>> This is a minimal driver that does not support burst mode,
>> interrupts, DMA or hardware triggers.
>>
>> User manual with register description can be found on:
>> LPC18xx: www.nxp.com/documents/user_manual/UM10430.pdf
>> LPC43xx: www.nxp.com/documents/user_manual/UM10503.pdf
>>
>> Signed-off-by: Joachim Eastwood <manabian@gmail.com>
>> ---
>> +/* Data registers bits */
>
> 'Data register bits' maybe
>
>> +     adc->vref = devm_regulator_get(&pdev->dev, "vref");
>> +     if (IS_ERR(adc->vref)) {
>> +             dev_err(&pdev->dev, "error get regulator\n");
>
> getting
>
>> +             return PTR_ERR(adc->vref);
>> +     }
>> +
>> +     indio_dev->name = dev_name(&pdev->dev);
>> +     indio_dev->dev.parent = &pdev->dev;
>> +     indio_dev->info = &lpc18xx_adc_info;
>> +     indio_dev->modes = INDIO_DIRECT_MODE;
>> +     indio_dev->channels = lpc18xx_adc_iio_channels;
>> +     indio_dev->num_channels = ARRAY_SIZE(lpc18xx_adc_iio_channels);
>> +
>> +     ret = regulator_enable(adc->vref);
>> +     if (ret) {
>> +             dev_err(&pdev->dev, "unable to enable regulator\n");
>> +             return ret;
>> +     }
>> +
>> +     ret = clk_prepare_enable(adc->clk);
>> +     if (ret) {
>> +             dev_err(&pdev->dev, "unable to enable clock.\n");
>
> maybe delete '.', it's the only message with a full stop

I will fix them all in the next version. I also noticed that a couple
of your comments also apply to the dac driver.

Thanks for looking through!


regards,
Joachim Eastwood

Re: [PATCH 0/4] Support for analog peripherals on LPC18xx familiy

[Rob Herring]

On Mon, Feb 29, 2016 at 1:05 PM, Joachim Eastwood <manabian@gmail.com> wrote:
> This patch set adds support for the analog (ADC and DAC) peripherals
> found on NXP LPC18xx/43xx SoCs. The ADC is a SAR converter with 10-bit
> resolution and 8 muxed inputs. The DAC is a simple single channel 10-
> bit DAC.
>
> Note that these drivers do not support all the features found on the
> peripherals. DMA and interrupts are not supported in either drivers.
> The ADC driver also lack 'burst-mode' and hardware triggers. So for
> now the ADC is limited to single shot samples.
>
> Both drivers tested on Embedded Artists' LPC4357 Developer's Kit.
>
> Based on iio/testing branch from 29.02.15.
>
>
> Joachim Eastwood (4):
>   iio: adc: add NXP LPC18xx ADC driver
>   dt: document NXP LPC1850 ADC driver bindings
>   iio: dac: add NXP LPC18xx DAC driver
>   dt: document NXP LPC1850 DAC driver bindings

You need to send bindings to the DT list.

Rob

Re: [PATCH 0/4] Support for analog peripherals on LPC18xx familiy

[Joachim Eastwood]

Hi Rob,

On 1 March 2016 at 21:33, Rob Herring <robh+dt@kernel.org> wrote:
> On Mon, Feb 29, 2016 at 1:05 PM, Joachim Eastwood <manabian@gmail.com> wrote:
>> This patch set adds support for the analog (ADC and DAC) peripherals
>> found on NXP LPC18xx/43xx SoCs. The ADC is a SAR converter with 10-bit
>> resolution and 8 muxed inputs. The DAC is a simple single channel 10-
>> bit DAC.
>>
>> Note that these drivers do not support all the features found on the
>> peripherals. DMA and interrupts are not supported in either drivers.
>> The ADC driver also lack 'burst-mode' and hardware triggers. So for
>> now the ADC is limited to single shot samples.
>>
>> Both drivers tested on Embedded Artists' LPC4357 Developer's Kit.
>>
>> Based on iio/testing branch from 29.02.15.
>>
>>
>> Joachim Eastwood (4):
>>   iio: adc: add NXP LPC18xx ADC driver
>>   dt: document NXP LPC1850 ADC driver bindings
>>   iio: dac: add NXP LPC18xx DAC driver
>>   dt: document NXP LPC1850 DAC driver bindings
>
> You need to send bindings to the DT list.

ah, my bad. I was pretty sure I added it when I did format-patch, but
it seems to have been lost along the way...

Either way there will be a v2 and I will make sure to cc the DT list then.

Thanks for reporting.


regards,
Joachim Eastwood

Re: [PATCH 0/4] Support for analog peripherals on LPC18xx familiy

[Jonathan Cameron]

On 29/02/16 19:05, Joachim Eastwood wrote:
> This patch set adds support for the analog (ADC and DAC) peripherals
> found on NXP LPC18xx/43xx SoCs. The ADC is a SAR converter with 10-bit
> resolution and 8 muxed inputs. The DAC is a simple single channel 10-
> bit DAC.
> 
> Note that these drivers do not support all the features found on the
> peripherals. DMA and interrupts are not supported in either drivers.
> The ADC driver also lack 'burst-mode' and hardware triggers. So for
> now the ADC is limited to single shot samples.
> 
> Both drivers tested on Embedded Artists' LPC4357 Developer's Kit.
> 
> Based on iio/testing branch from 29.02.15.
Series looks pretty good.  Will do a review of V2 - right now I haven't
found anything to add to what Peter found.

Nice little ADC from a quick read of the data sheet.  Not too complex
but still well featured.
> 
> 
> Joachim Eastwood (4):
>   iio: adc: add NXP LPC18xx ADC driver
>   dt: document NXP LPC1850 ADC driver bindings
>   iio: dac: add NXP LPC18xx DAC driver
>   dt: document NXP LPC1850 DAC driver bindings
> 
>  .../devicetree/bindings/iio/adc/lpc1850-adc.txt    |  21 ++
>  .../devicetree/bindings/iio/dac/lpc1850-dac.txt    |  20 ++
>  drivers/iio/adc/Kconfig                            |  10 +
>  drivers/iio/adc/Makefile                           |   1 +
>  drivers/iio/adc/lpc18xx_adc.c                      | 226 +++++++++++++++++++++
>  drivers/iio/dac/Kconfig                            |  10 +
>  drivers/iio/dac/Makefile                           |   1 +
>  drivers/iio/dac/lpc18xx_dac.c                      | 204 +++++++++++++++++++
>  8 files changed, 493 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/lpc1850-adc.txt
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/lpc1850-dac.txt
>  create mode 100644 drivers/iio/adc/lpc18xx_adc.c
>  create mode 100644 drivers/iio/dac/lpc18xx_dac.c
>