[PATCH linux dev-4.13 v2 2/2] ADC: npcm: add NPCM7xx ADC driver
Tomer Maimon
tmaimon77 at gmail.com
Sun Jan 7 19:51:31 AEDT 2018
Add Nuvoton BMC NPCM7xx Analog-to-digital
converter (ADC) driver
The NPCM7xx ADC is a 10-bit converter for eight channel
inputs, the ADC module includes an eight-to-one multiplexer.
Signed-off-by: Tomer Maimon <tmaimon77 at gmail.com>
---
drivers/iio/adc/Kconfig | 9 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/npcm7xx-adc.c | 352 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 362 insertions(+)
create mode 100644 drivers/iio/adc/npcm7xx-adc.c
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 614fa41559b1..77705fde21ca 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -857,4 +857,13 @@ config XILINX_XADC
The driver can also be build as a module. If so, the module will be called
xilinx-xadc.
+config NPCM7XX_ADC
+ tristate "NPCM7XX ADC driver"
+ depends on ARCH_NPCM7XX || COMPILE_TEST
+ depends on HAS_IOMEM
+ help
+ Say yes here to build support for NPCM7XX ADC.
+ This driver can also be built as a module. If so, the module will be
+ called npcm750_adc.
+
endmenu
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index b546736a5541..871074d7b0cd 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -78,3 +78,4 @@ obj-$(CONFIG_VF610_ADC) += vf610_adc.o
obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
xilinx-xadc-y := xilinx-xadc-core.o xilinx-xadc-events.o
obj-$(CONFIG_XILINX_XADC) += xilinx-xadc.o
+obj-$(CONFIG_NPCM7XX_ADC) += npcm7xx-adc.o
diff --git a/drivers/iio/adc/npcm7xx-adc.c b/drivers/iio/adc/npcm7xx-adc.c
new file mode 100644
index 000000000000..ee218a395982
--- /dev/null
+++ b/drivers/iio/adc/npcm7xx-adc.c
@@ -0,0 +1,352 @@
+/*
+ * Copyright (c) 2014-2017 Nuvoton Technology corporation.
+ *
+ * Released under the GPLv2 only.
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/signal.h>
+#include <linux/spinlock.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/iio/sysfs.h>
+
+#include <linux/clk.h>
+
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+static struct regmap *rst_regmap;
+
+#define IPSRST1_OFFSET 0x020
+
+struct npcm7xx_adc {
+ struct device *dev;
+ void __iomem *regs;
+ struct clk *adc_clk;
+ u32 vref;
+ u32 adc_clk_rate;
+ u32 ADCReading;
+ u8 ADCChannelNum;
+};
+
+/* ADC registers */
+#define NPCM7XX_ADCCON 0x00
+#define NPCM7XX_ADCDATA 0x04
+
+/* ADCCON Register Bits */
+#define NPCM7XX_ADCCON_ADC_INT_EN BIT(21)
+#define NPCM7XX_ADCCON_REFSEL BIT(19)
+#define NPCM7XX_ADCCON_ADC_INT BIT(18)
+#define NPCM7XX_ADCCON_ADC_EN BIT(17)
+#define NPCM7XX_ADCCON_ADC_RST BIT(16)
+#define NPCM7XX_ADCCON_ADC_CONV BIT(13)
+
+#define NPCM7XX_ADCCON_ADCMUX(x) (((x) & 0x0F)<<24)
+#define NPCM7XX_ADCCON_ADC_DIV(x) (((x) & 0xFF)<<24)
+#define NPCM7XX_ADCCON_ADC_DATA_MASK(x) ((x) & 0x3FF)
+#define NPCM7XX_ADCCON_MUXMASK (0x0F<<24)
+
+/* ADC General Defintion */
+#define NPCM7XX_ADC_INPUT_CLK_DIV 0
+#define NPCM7XX_ADC_CONVERT_MAX_RETRY_CNT 1000
+
+#define NPCM7XX_ADC_MAX_CHNL_NUM 8
+
+#define NPCM7XX_ADC_CHNL0_ADCI0 0
+#define NPCM7XX_ADC_CHNL1_ADCI1 1
+#define NPCM7XX_ADC_CHNL2_ADCI2 2
+#define NPCM7XX_ADC_CHNL3_ADCI3 3
+#define NPCM7XX_ADC_CHNL4_ADCI4 4
+#define NPCM7XX_ADC_CHNL5_ADCI5 5
+#define NPCM7XX_ADC_CHNL6_ADCI6 6
+#define NPCM7XX_ADC_CHNL7_ADCI7 7
+
+#define ADC_MAX_CLOCK 12500000
+#define VREF_MVOLT 2048 //vref = 2.000v
+
+#define NPCM7XX_ADC_CHAN(_idx) { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = (_idx), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+}
+
+static const struct iio_chan_spec npcm7xx_adc_iio_channels[] = {
+ NPCM7XX_ADC_CHAN(0),
+ NPCM7XX_ADC_CHAN(1),
+ NPCM7XX_ADC_CHAN(2),
+ NPCM7XX_ADC_CHAN(3),
+ NPCM7XX_ADC_CHAN(4),
+ NPCM7XX_ADC_CHAN(5),
+ NPCM7XX_ADC_CHAN(6),
+ NPCM7XX_ADC_CHAN(7),
+};
+
+//#define ADC_DEBUG
+
+#ifdef ADC_DEBUG
+static char *S_ADCChnlString[] = {
+ "ADCI0", "ADCI1", "ADCI2", "ADCI3", "ADCI4", "ADCI5", "ADCI6", "ADCI7"
+};
+#define PDEBUG(fmt, args...) pr_info("aess_adcdrv %s() " fmt, __func__, ##args)
+#else
+#define PDEBUG(fmt, args...)
+#endif
+#define PERROR(fmt, args...) pr_err("aess_adcdrv %s(): " fmt, __func__, ##args)
+
+static int adcsensor_read(struct npcm7xx_adc *info)
+{
+ u8 u8ChannelNum = info->ADCChannelNum;
+ u32 regtemp = 0;
+ int cnt = 0;
+
+ /* Select ADC channal */
+ regtemp = ioread32(info->regs + NPCM7XX_ADCCON);
+ regtemp &= ~NPCM7XX_ADCCON_MUXMASK;
+
+ iowrite32((u32) (regtemp | NPCM7XX_ADCCON_ADCMUX(u8ChannelNum) |
+ NPCM7XX_ADCCON_ADC_EN | NPCM7XX_ADCCON_REFSEL),
+ info->regs + NPCM7XX_ADCCON);
+
+ /* Activate convert the ADC input */
+ regtemp = ioread32(info->regs + NPCM7XX_ADCCON);
+ iowrite32((u32) (regtemp | NPCM7XX_ADCCON_ADC_CONV),
+ info->regs + NPCM7XX_ADCCON);
+
+ /* Wait value */
+ while (((regtemp = ioread32(info->regs + NPCM7XX_ADCCON)) &
+ NPCM7XX_ADCCON_ADC_CONV) != 0) {
+ if (cnt < NPCM7XX_ADC_CONVERT_MAX_RETRY_CNT)
+ cnt++;
+ else {
+ PERROR("ADC CONVERT FAIL - Timeout\n");
+ PERROR("NPCM7XX_ADCCON=0x%08X, ADC_MUX=%d u8ChannelNum="
+ "%d!!\n", regtemp, (regtemp>>24)&0xF,
+ u8ChannelNum);
+ if (((regtemp>>24) & 0xF) != u8ChannelNum)
+ PERROR("ADC_MUX != u8ChannelNum, I suspect that"
+ " 2 threads are trying to access this "
+ "read and it is not protected "
+ "by mutex\n");
+
+ /* if convertion failed - reset ADC module */
+ regmap_write(rst_regmap, IPSRST1_OFFSET, 0x08000000);
+ msleep(100);
+ regmap_write(rst_regmap, IPSRST1_OFFSET, 0x0);
+ msleep(100);
+ PERROR("RESET ADC Complete\n");
+ return (-EAGAIN);
+ }
+ }
+
+/* When an ADC conversion operation finished, a delay must be added before
+ * the next conversion operation.
+ * The delay depend on the ADC clock:
+ * When ADC clock is 0.5 MHz: delay is 4 us.
+ * When ADC clock is 12.5 MHz: delay is 160 ns.
+ *
+ * In the current driver the ADC clock is 12.5MHz, so delay is not needed.
+ * (already the R/W register take more than 160ns)
+ * If the ADC clock will be lower than 12.5MHz please add delay according
+ * the details above
+ * udelay(conv_delay);
+ */
+
+ /* finish to convert */
+ info->ADCReading = NPCM7XX_ADCCON_ADC_DATA_MASK
+ (ioread32(info->regs + NPCM7XX_ADCDATA));
+
+ PDEBUG("[%d_%s] ADCReading=%ld [%ldmV]\n",
+ u8ChannelNum, S_ADCChnlString[u8ChannelNum],
+ (long int)info->ADCReading,
+ (long int)(info->ADCReading * info->vref / 1024));
+
+ return 0;
+}
+
+static int npcm7xx_adc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val, int *val2,
+ long mask)
+{
+ int err_check;
+ struct npcm7xx_adc *info = iio_priv(indio_dev);
+
+ info->ADCChannelNum = chan->channel;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+
+ switch (info->ADCChannelNum) {
+ case NPCM7XX_ADC_CHNL0_ADCI0:
+ case NPCM7XX_ADC_CHNL1_ADCI1:
+ case NPCM7XX_ADC_CHNL2_ADCI2:
+ case NPCM7XX_ADC_CHNL3_ADCI3:
+ case NPCM7XX_ADC_CHNL4_ADCI4:
+ case NPCM7XX_ADC_CHNL5_ADCI5:
+ case NPCM7XX_ADC_CHNL6_ADCI6:
+ case NPCM7XX_ADC_CHNL7_ADCI7:
+ mutex_lock(&indio_dev->mlock);
+ err_check = adcsensor_read(info);
+ PDEBUG("%d = aess_adcsensor_read()\n", err_check);
+ if (err_check) {
+ PERROR("err_check %d\n", err_check);
+ mutex_unlock(&indio_dev->mlock);
+ return err_check;
+ }
+ *val = info->ADCReading;
+ mutex_unlock(&indio_dev->mlock);
+ return IIO_VAL_INT;
+ default:
+ PERROR("aess_adcsensor_ioctl, Unsupport channel number"
+ " [%d]!\n", info->ADCChannelNum);
+ err_check = -ENODEV;
+ break;
+ }
+ break;
+
+ default:
+ PERROR("aess_adcsensor_ioctl, command error!!!\n");
+ err_check = -EINVAL;
+ }
+
+ /* 0->ok, minus->fail */
+ return err_check;
+}
+
+static const struct iio_info npcm7xx_adc_iio_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = &npcm7xx_adc_read_raw,
+};
+
+static const struct of_device_id npcm7xx_adc_match[] = {
+ { .compatible = "nuvoton,npcm750-adc", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, npcm7xx_adc_match);
+
+
+static int npcm7xx_adc_probe(struct platform_device *pdev)
+{
+ struct npcm7xx_adc *info;
+ struct iio_dev *indio_dev;
+ struct resource *mem;
+ struct device *dev = &pdev->dev;
+ int ret;
+ u32 regtemp = 0;
+
+ 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);
+ info->dev = &pdev->dev;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ info->regs = devm_ioremap_resource(&pdev->dev, mem);
+ if (IS_ERR(info->regs)) {
+ ret = PTR_ERR(info->regs);
+ dev_err(&pdev->dev, "Failed to remap adc memory, err = %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = of_property_read_u32(dev->of_node, "vref", &info->vref);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed getting reference voltage, Assuming"
+ " reference voltage 2V(2048)\n");
+ info->vref = VREF_MVOLT;
+ ret = 0;
+ }
+
+ info->adc_clk = devm_clk_get(&pdev->dev, "clk_adc");
+ if (IS_ERR(info->adc_clk)) {
+ dev_err(&pdev->dev, "ADC clock failed: can't read clk. "
+ "Assuming ADC clock Rate 12.5MHz\n");
+ info->adc_clk_rate = ADC_MAX_CLOCK;
+ } else {
+ /* calculate ADC clock divider */
+ regtemp = ioread32(info->regs + NPCM7XX_ADCCON);
+ regtemp = regtemp >> 1;
+ regtemp &= 0xff;
+
+ info->adc_clk_rate = clk_get_rate(info->adc_clk) /
+ ((regtemp+1)*2);
+ }
+
+ rst_regmap = syscon_regmap_lookup_by_compatible("nuvoton,npcm750-rst");
+ if (IS_ERR(rst_regmap)) {
+ pr_err("%s: failed to find nuvoton,npcm750-rst\n", __func__);
+ return IS_ERR(rst_regmap);
+ }
+
+ pr_info("ADC clock Rate %d\n", info->adc_clk_rate);
+
+ /** Enable the ADC Module **/
+ iowrite32((u32) NPCM7XX_ADCCON_ADC_EN, info->regs + NPCM7XX_ADCCON);
+
+ platform_set_drvdata(pdev, indio_dev);
+
+ indio_dev->name = dev_name(&pdev->dev);
+ indio_dev->dev.parent = &pdev->dev;
+ indio_dev->info = &npcm7xx_adc_iio_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = npcm7xx_adc_iio_channels;
+ indio_dev->num_channels = ARRAY_SIZE(npcm7xx_adc_iio_channels);
+
+ ret = iio_device_register(indio_dev);
+ if (ret) {
+ dev_err(&pdev->dev, "Couldn't register the device.\n");
+ clk_disable_unprepare(info->adc_clk);
+ return ret;
+ }
+
+ pr_info("NPCM7XX ADC driver probed\n");
+
+ return 0;
+}
+
+static int npcm7xx_adc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct npcm7xx_adc *info = iio_priv(indio_dev);
+ u32 regtemp = 0;
+
+ regtemp = ioread32(info->regs + NPCM7XX_ADCCON);
+
+ /* Disable the ADC Module */
+ iowrite32((u32) (regtemp & ~NPCM7XX_ADCCON_ADC_EN),
+ info->regs + NPCM7XX_ADCCON);
+
+ iio_device_unregister(indio_dev);
+
+ pr_info("NPCM7XX ADC driver removed\n");
+
+ return 0;
+}
+
+static struct platform_driver npcm7xx_adc_driver = {
+ .probe = npcm7xx_adc_probe,
+ .remove = npcm7xx_adc_remove,
+ .driver = {
+ .name = "npcm7xx_adc",
+ .of_match_table = npcm7xx_adc_match,
+ },
+};
+
+module_platform_driver(npcm7xx_adc_driver);
+
+MODULE_DESCRIPTION("NPCM7XX ADC Sensor Driver");
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon at nuvoton.com>");
+MODULE_LICENSE("GPL v2");
--
2.14.1
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