[PATCH v2 1/5] iio:adc:at91_adc8xx: introduce new atmel adc driver
From: Ludovic Desroches
Date: Wed Jan 06 2016 - 11:12:58 EST
This driver supports the new version of the Atmel ADC device introduced
with the SAMA5D2 SoC family.
Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
---
.../devicetree/bindings/iio/adc/at91_adc8xx.txt | 28 ++
drivers/iio/adc/Kconfig | 11 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/at91_adc8xx.c | 461 +++++++++++++++++++++
4 files changed, 501 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/at91_adc8xx.txt
create mode 100644 drivers/iio/adc/at91_adc8xx.c
diff --git a/Documentation/devicetree/bindings/iio/adc/at91_adc8xx.txt b/Documentation/devicetree/bindings/iio/adc/at91_adc8xx.txt
new file mode 100644
index 0000000..14fe441
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/at91_adc8xx.txt
@@ -0,0 +1,28 @@
+* AT91 SAMA5D2 Analog to Digital Converter (ADC)
+
+Required properties:
+ - compatible: Should be "atmel,sama5d2-adc".
+ - reg: Should contain ADC registers location and length.
+ - interrupts: Should contain the IRQ line for the ADC.
+ - clocks: phandle to device clock.
+ - clock-names: Must be "adc_clk".
+ - vref-supply: Supply used as reference for conversions.
+ - vddana-supply: Supply for the adc device.
+ - atmel,min-sample-rate: Minimum sampling rate, it depends on SoC.
+ - atmel,max-sample-rate: Maximum sampling rate, it depends on SoC.
+ - atmel,startup-time-ms: Startup time expressed in ms, it depends on SoC.
+
+Example:
+
+adc: adc@fc030000 {
+ compatible = "atmel,sama5d2-adc";
+ reg = <0xfc030000 0x100>;
+ interrupts = <40 IRQ_TYPE_LEVEL_HIGH 7>;
+ clocks = <&adc_clk>;
+ clock-names = "adc_clk";
+ atmel,min-sample-rate = <200000>;
+ atmel,max-sample-rate = <20000000>;
+ atmel,startup-time-ms = <4>;
+ vddana-supply = <&vdd_3v3_lp_reg>;
+ vref-supply = <&vdd_3v3_lp_reg>;
+}
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 605ff42..ee45468 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -131,6 +131,17 @@ config AT91_ADC
To compile this driver as a module, choose M here: the module will be
called at91_adc.
+config AT91_ADC8xx
+ tristate "Atmel AT91 ADC 8xx"
+ depends on ARCH_AT91
+ depends on INPUT
+ help
+ Say yes here to build support for Atmel ADC 8xx which is available
+ from SAMA5D2 SoC family.
+
+ To compile this driver as a module, choose M here: the module will be
+ called at91_adc8xx.
+
config AXP288_ADC
tristate "X-Powers AXP288 ADC driver"
depends on MFD_AXP20X
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 6435780..c0d5d02 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_AD7793) += ad7793.o
obj-$(CONFIG_AD7887) += ad7887.o
obj-$(CONFIG_AD799X) += ad799x.o
obj-$(CONFIG_AT91_ADC) += at91_adc.o
+obj-$(CONFIG_AT91_ADC8xx) += at91_adc8xx.o
obj-$(CONFIG_AXP288_ADC) += axp288_adc.o
obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
diff --git a/drivers/iio/adc/at91_adc8xx.c b/drivers/iio/adc/at91_adc8xx.c
new file mode 100644
index 0000000..bed9574
--- /dev/null
+++ b/drivers/iio/adc/at91_adc8xx.c
@@ -0,0 +1,461 @@
+/*
+ * Atmel ADC driver for SAMA5D2 devices and later.
+ *
+ * Copyright (C) 2015 Atmel,
+ * 2015 Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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/bitops.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/regulator/consumer.h>
+
+#define AT91_ADC8XX_CR 0x00 /* Control Register */
+#define AT91_ADC8XX_CR_SWRST BIT(0) /* Software Reset */
+#define AT91_ADC8XX_CR_START BIT(1) /* Start Conversion */
+#define AT91_ADC8XX_CR_TSCALIB BIT(2) /* Touchscreen Calibration */
+#define AT91_ADC8XX_CR_CMPRST BIT(4) /* Comparison Restart */
+#define AT91_ADC8XX_MR 0x04 /* Mode Register */
+#define AT91_ADC8XX_MR_TRGSEL(v) ((v) << 1) /* Trigger Selection */
+#define AT91_ADC8XX_MR_TRGSEL_TRIG0 0 /* ADTRG */
+#define AT91_ADC8XX_MR_TRGSEL_TRIG1 1 /* TIOA0 */
+#define AT91_ADC8XX_MR_TRGSEL_TRIG2 2 /* TIOA1 */
+#define AT91_ADC8XX_MR_TRGSEL_TRIG3 3 /* TIOA2 */
+#define AT91_ADC8XX_MR_TRGSEL_TRIG4 4 /* PWM event line 0 */
+#define AT91_ADC8XX_MR_TRGSEL_TRIG5 5 /* PWM event line 1 */
+#define AT91_ADC8XX_MR_TRGSEL_TRIG6 6 /* TIOA3 */
+#define AT91_ADC8XX_MR_TRGSEL_TRIG7 7 /* RTCOUT0 */
+#define AT91_ADC8XX_MR_SLEEP BIT(5) /* Sleep Mode */
+#define AT91_ADC8XX_MR_FWUP BIT(6) /* Fast Wake Up */
+#define AT91_ADC8XX_MR_PRESCAL(v) ((v) << AT91_ADC8XX_MR_PRESCAL_OFFSET) /* Prescaler Rate Selection */
+#define AT91_ADC8XX_MR_PRESCAL_OFFSET 8
+#define AT91_ADC8XX_MR_PRESCAL_MAX 0xff
+#define AT91_ADC8XX_MR_STARTUP(v) ((v) << 16) /* Startup Time */
+#define AT91_ADC8XX_MR_ANACH BIT(23) /* Analog Change */
+#define AT91_ADC8XX_MR_TRACKTIM(v) ((v) << 24) /* Tracking Time */
+#define AT91_ADC8XX_MR_TRACKTIM_MAX 0xff
+#define AT91_ADC8XX_MR_TRANSFER(v) ((v) << 28) /* Transfer Time */
+#define AT91_ADC8XX_MR_TRANSFER_MAX 0x3
+#define AT91_ADC8XX_MR_USEQ BIT(31) /* Use Sequence Enable */
+#define AT91_ADC8XX_SEQR1 0x08 /* Channel Sequence Register 1 */
+#define AT91_ADC8XX_SEQR2 0x0c /* Channel Sequence Register 2 */
+#define AT91_ADC8XX_CHER 0x10 /* Channel Enable Register */
+#define AT91_ADC8XX_CHDR 0x14 /* Channel Disable Register */
+#define AT91_ADC8XX_CHSR 0x18 /* Channel Status Register */
+#define AT91_ADC8XX_LCDR 0x20 /* Last Converted Data Register */
+#define AT91_ADC8XX_IER 0x24 /* Interrupt Enable Register */
+#define AT91_ADC8XX_IDR 0x28 /* Interrupt Disable Register */
+#define AT91_ADC8XX_IMR 0x2c /* Interrupt Mask Register */
+#define AT91_ADC8XX_ISR 0x30 /* Interrupt Status Register */
+#define AT91_ADC8XX_LCTMR 0x34 /* Last Channel Trigger Mode Register */
+#define AT91_ADC8XX_LCCWR 0x38 /* Last Channel Compare Window Register */
+#define AT91_ADC8XX_OVER 0x3c /* Overrun Status Register */
+#define AT91_ADC8XX_EMR 0x40 /* Extended Mode Register */
+#define AT91_ADC8XX_CWR 0x44 /* Compare Window Register */
+#define AT91_ADC8XX_CGR 0x48 /* Channel Gain Register */
+#define AT91_ADC8XX_COR 0x4c /* Channel Offset Register */
+#define AT91_ADC8XX_CDR0 0x50 /* Channel Data Register 0 */
+#define AT91_ADC8XX_ACR 0x94 /* Analog Control Register */
+#define AT91_ADC8XX_TSMR 0xb0 /* Touchscreen Mode Register */
+#define AT91_ADC8XX_XPOSR 0xb4 /* Touchscreen X Position Register */
+#define AT91_ADC8XX_YPOSR 0xb8 /* Touchscreen Y Position Register */
+#define AT91_ADC8XX_PRESSR 0xbc /* Touchscreen Pressure Register */
+#define AT91_ADC8XX_TRGR 0xc0 /* Trigger Register */
+#define AT91_ADC8XX_COSR 0xd0 /* Correction Select Register */
+#define AT91_ADC8XX_CVR 0xd4 /* Correction Value Register */
+#define AT91_ADC8XX_CECR 0xd8 /* Channel Error Correction Register */
+#define AT91_ADC8XX_WPMR 0xe4 /* Write Protection Mode Register */
+#define AT91_ADC8XX_WPSR 0xe8 /* Write Protection Status Register */
+#define AT91_ADC8XX_VERSION 0xfc /* Version Register */
+
+#define AT91_AT91_ADC8XX_CHAN(num, addr) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .channel = num, \
+ .address = addr, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 12, \
+ }, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .datasheet_name = "CH"#num, \
+ .indexed = 1, \
+ }
+
+#define at91_adc_readl(st, reg) readl_relaxed(st->base + reg)
+#define at91_adc_writel(st, reg, val) writel_relaxed(val, st->base + reg)
+
+struct at91_adc_soc_info {
+ unsigned startup_time;
+ unsigned min_sample_rate;
+ unsigned max_sample_rate;
+};
+
+struct at91_adc_state {
+ void __iomem *base;
+ int irq;
+ struct clk *per_clk;
+ struct regulator *reg;
+ struct regulator *vref;
+ u32 vref_uv;
+ const struct iio_chan_spec *chan;
+ bool conversion_done;
+ u32 conversion_value;
+ struct at91_adc_soc_info soc_info;
+ wait_queue_head_t wq_data_available;
+ struct mutex lock;
+};
+
+static const struct iio_chan_spec at91_adc_channels[] = {
+ AT91_AT91_ADC8XX_CHAN(0, 0x50),
+ AT91_AT91_ADC8XX_CHAN(1, 0x54),
+ AT91_AT91_ADC8XX_CHAN(2, 0x58),
+ AT91_AT91_ADC8XX_CHAN(3, 0x5c),
+ AT91_AT91_ADC8XX_CHAN(4, 0x60),
+ AT91_AT91_ADC8XX_CHAN(5, 0x64),
+ AT91_AT91_ADC8XX_CHAN(6, 0x68),
+ AT91_AT91_ADC8XX_CHAN(7, 0x6c),
+ AT91_AT91_ADC8XX_CHAN(8, 0x70),
+ AT91_AT91_ADC8XX_CHAN(9, 0x74),
+ AT91_AT91_ADC8XX_CHAN(10, 0x78),
+ AT91_AT91_ADC8XX_CHAN(11, 0x7c),
+};
+
+static unsigned at91_adc_startup_time(unsigned startup_time_min,
+ unsigned adc_clk_khz)
+{
+ const unsigned startup_lookup[] = {
+ 0, 8, 16, 24,
+ 64, 80, 96, 112,
+ 512, 576, 640, 704,
+ 768, 832, 896, 960
+ };
+ unsigned ticks_min, i;
+
+ /*
+ * Since the adc frequency is checked before, there is no reason
+ * to not meet the startup time constraint.
+ */
+
+ ticks_min = startup_time_min * adc_clk_khz / 1000;
+ for (i = 0; i < ARRAY_SIZE(startup_lookup); i++)
+ if (startup_lookup[i] > ticks_min)
+ break;
+
+ return i;
+}
+
+static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
+{
+ struct iio_dev *indio_dev = iio_priv_to_dev(st);
+ unsigned f_per, prescal, startup;
+
+ f_per = clk_get_rate(st->per_clk);
+ prescal = (f_per / (2 * freq)) - 1;
+
+ startup = at91_adc_startup_time(st->soc_info.startup_time,
+ freq / 1000);
+
+ at91_adc_writel(st, AT91_ADC8XX_MR,
+ AT91_ADC8XX_MR_TRANSFER(2)
+ | AT91_ADC8XX_MR_STARTUP(startup)
+ | AT91_ADC8XX_MR_PRESCAL(prescal));
+
+ dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
+ freq, startup, prescal);
+}
+
+static ssize_t at91_adc_show_samp_freq(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct at91_adc_state *st = iio_priv(dev_to_iio_dev(dev));
+ unsigned f_adc, f_per = clk_get_rate(st->per_clk);
+ unsigned mr, prescal;
+
+ mr = at91_adc_readl(st, AT91_ADC8XX_MR);
+ prescal = (mr >> AT91_ADC8XX_MR_PRESCAL_OFFSET)
+ & AT91_ADC8XX_MR_PRESCAL_MAX;
+ f_adc = f_per / (2 * (prescal + 1));
+
+ return sprintf(buf, "%d\n", f_adc);
+}
+
+static ssize_t at91_adc_store_samp_freq(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct at91_adc_state *st = iio_priv(dev_to_iio_dev(dev));
+ unsigned val;
+ int ret;
+
+ ret = kstrtouint(buf, 10, &val);
+ if (ret)
+ return -EINVAL;
+
+ if (val < st->soc_info.min_sample_rate ||
+ val > st->soc_info.max_sample_rate)
+ return -EINVAL;
+
+ at91_adc_setup_samp_freq(st, val);
+
+ return len;
+}
+
+static IIO_DEV_ATTR_SAMP_FREQ(S_IRUGO | S_IWUSR,
+ at91_adc_show_samp_freq,
+ at91_adc_store_samp_freq);
+
+static struct attribute *at91_adc_event_attributes[] = {
+ &iio_dev_attr_sampling_frequency.dev_attr.attr,
+ NULL,
+};
+
+static struct attribute_group at91_adc_event_attribute_group = {
+ .attrs = at91_adc_event_attributes,
+};
+
+static irqreturn_t at91_adc_interrupt(int irq, void *private)
+{
+ struct iio_dev *indio = private;
+ struct at91_adc_state *st = iio_priv(indio);
+ u32 status = at91_adc_readl(st, AT91_ADC8XX_ISR);
+
+ status &= at91_adc_readl(st, AT91_ADC8XX_IMR);
+ if (status & 0xffff) {
+ st->conversion_value = at91_adc_readl(st, st->chan->address);
+ st->conversion_done = true;
+ wake_up_interruptible(&st->wq_data_available);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int at91_adc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct at91_adc_state *st = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&st->lock);
+
+ st->chan = chan;
+
+ at91_adc_writel(st, AT91_ADC8XX_CHER, BIT(chan->channel));
+ at91_adc_writel(st, AT91_ADC8XX_IER, BIT(chan->channel));
+ at91_adc_writel(st, AT91_ADC8XX_CR, AT91_ADC8XX_CR_START);
+
+ ret = wait_event_interruptible_timeout(st->wq_data_available,
+ st->conversion_done,
+ msecs_to_jiffies(1000));
+ if (ret == 0)
+ ret = -ETIMEDOUT;
+
+ if (ret > 0) {
+ *val = st->conversion_value;
+ ret = IIO_VAL_INT;
+ st->conversion_done = false;
+ }
+
+ at91_adc_writel(st, AT91_ADC8XX_IDR, BIT(chan->channel));
+ at91_adc_writel(st, AT91_ADC8XX_CHDR, BIT(chan->channel));
+
+ mutex_unlock(&st->lock);
+ return ret;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = st->vref_uv / 1000;
+ *val2 = chan->scan_type.realbits;
+ return IIO_VAL_FRACTIONAL_LOG2;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info at91_adc_info = {
+ .read_raw = &at91_adc_read_raw,
+ .driver_module = THIS_MODULE,
+ .event_attrs = &at91_adc_event_attribute_group,
+};
+
+static int at91_adc_probe(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev;
+ struct at91_adc_state *st;
+ struct resource *res;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&pdev->dev,
+ sizeof(struct at91_adc_state));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ indio_dev->dev.parent = &pdev->dev;
+ indio_dev->name = dev_name(&pdev->dev);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &at91_adc_info;
+ indio_dev->channels = at91_adc_channels;
+ indio_dev->num_channels = ARRAY_SIZE(at91_adc_channels);
+
+ st = iio_priv(indio_dev);
+
+ ret = of_property_read_u32(pdev->dev.of_node, "atmel,min-sample-rate",
+ &st->soc_info.min_sample_rate);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "invalid or missing value for atmel,min-sample-rate\n");
+ return ret;
+ }
+
+ ret = of_property_read_u32(pdev->dev.of_node, "atmel,max-sample-rate",
+ &st->soc_info.max_sample_rate);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "invalid or missing value for atmel,max-sample-rate\n");
+ return ret;
+ }
+
+ ret = of_property_read_u32(pdev->dev.of_node, "atmel,startup-time-ms",
+ &st->soc_info.startup_time);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "invalid or missing value for atmel,startup-time-ms\n");
+ return ret;
+ }
+
+ init_waitqueue_head(&st->wq_data_available);
+ mutex_init(&st->lock);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -EINVAL;
+
+ st->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(st->base))
+ return PTR_ERR(st->base);
+
+ st->irq = platform_get_irq(pdev, 0);
+ if (st->irq <= 0) {
+ if (!st->irq)
+ st->irq = -ENXIO;
+
+ return st->irq;
+ }
+
+ st->per_clk = devm_clk_get(&pdev->dev, "adc_clk");
+ if (IS_ERR(st->per_clk))
+ return PTR_ERR(st->per_clk);
+
+ st->reg = devm_regulator_get(&pdev->dev, "vddana");
+ if (IS_ERR(st->reg))
+ return PTR_ERR(st->reg);
+
+ st->vref = devm_regulator_get(&pdev->dev, "vref");
+ if (IS_ERR(st->vref))
+ return PTR_ERR(st->vref);
+
+ ret = devm_request_irq(&pdev->dev, st->irq, at91_adc_interrupt, 0,
+ pdev->dev.driver->name, indio_dev);
+ if (ret)
+ return ret;
+
+ ret = regulator_enable(st->reg);
+ if (ret)
+ return ret;
+
+ ret = regulator_enable(st->vref);
+ if (ret)
+ goto reg_disable;
+
+ st->vref_uv = regulator_get_voltage(st->vref);
+ if (st->vref_uv <= 0) {
+ ret = -EINVAL;
+ goto vref_disable;
+ }
+
+ at91_adc_writel(st, AT91_ADC8XX_CR, AT91_ADC8XX_CR_SWRST);
+ at91_adc_writel(st, AT91_ADC8XX_IDR, 0xffffffff);
+
+ at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);
+
+ ret = clk_prepare_enable(st->per_clk);
+ if (ret)
+ goto vref_disable;
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0)
+ goto per_clk_disable_unprepare;
+
+ dev_info(&pdev->dev, "version: %x\n",
+ readl_relaxed(st->base + AT91_ADC8XX_VERSION));
+
+ return 0;
+
+per_clk_disable_unprepare:
+ clk_disable_unprepare(st->per_clk);
+vref_disable:
+ regulator_disable(st->vref);
+reg_disable:
+ regulator_disable(st->reg);
+ return ret;
+}
+
+static int at91_adc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct at91_adc_state *st = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+
+ clk_disable_unprepare(st->per_clk);
+
+ regulator_disable(st->vref);
+ regulator_disable(st->reg);
+
+ return 0;
+}
+
+static const struct of_device_id at91_adc_dt_match[] = {
+ {
+ .compatible = "atmel,sama5d2-adc",
+ }, {
+ /* sentinel */
+ }
+};
+MODULE_DEVICE_TABLE(of, at91_adc_dt_match);
+
+static struct platform_driver at91_adc_driver = {
+ .probe = at91_adc_probe,
+ .remove = at91_adc_remove,
+ .driver = {
+ .name = "at91_adc8xx",
+ .of_match_table = at91_adc_dt_match,
+ },
+};
+module_platform_driver(at91_adc_driver)
+
+MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@xxxxxxxxx>");
+MODULE_DESCRIPTION("Atmel AT91 ADC 8xx");
+MODULE_LICENSE("GPL v2");
--
2.5.0
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