[PATCH 1/5] iio:adc:at91_adc8xx: introduce new atmel adc driver
From: Ludovic Desroches
Date: Mon Dec 21 2015 - 04:24:24 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 | 27 ++
drivers/iio/adc/Kconfig | 11 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/at91_adc8xx.c | 417 +++++++++++++++++++++
4 files changed, 456 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..64ad6a5
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/at91_adc8xx.txt
@@ -0,0 +1,27 @@
+* 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: phandles to clocks.
+ - clock-names: tuple listing clock names.
+ Required elements: "adc_clk", "adc_op_clk". "adc_clk" is the peripheral
+ clock, "adc_clk" is the sampling clock.
+ - vref-supply: Supply used as reference for conversions.
+
+Optional properties:
+ - vddana-supply: Supply for the adc device.
+
+
+Example:
+
+adc: adc@fc030000 {
+ compatible = "atmel,sama5d2-adc";
+ reg = <0xfc030000 0x100>;
+ interrupts = <40 IRQ_TYPE_LEVEL_HIGH 7>;
+ clocks = <&adc_clk>, <&adc_op_clk>;
+ clock-names = "adc_clk", "adc_op_clk";
+ 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 9162dfe..5819e41 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 91a65bf..d684a52 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..8b4a6e7
--- /dev/null
+++ b/drivers/iio/adc/at91_adc8xx.c
@@ -0,0 +1,417 @@
+/*
+ * 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/regulator/consumer.h>
+
+#define ADC_CR 0x00 /* Control Register */
+#define ADC_CR_SWRST BIT(0) /* Software Reset */
+#define ADC_CR_START BIT(1) /* Start Conversion */
+#define ADC_CR_TSCALIB BIT(2) /* Touchscreen Calibration */
+#define ADC_CR_CMPRST BIT(4) /* Comparison Restart */
+#define ADC_MR 0x04 /* Mode Register */
+#define ADC_MR_TRGSEL(v) (v << 1) /* Trigger Selection */
+#define ADC_MR_TRGSEL_TRIG0 0 /* ADTRG */
+#define ADC_MR_TRGSEL_TRIG1 1 /* TIOA0 */
+#define ADC_MR_TRGSEL_TRIG2 2 /* TIOA1 */
+#define ADC_MR_TRGSEL_TRIG3 3 /* TIOA2 */
+#define ADC_MR_TRGSEL_TRIG4 4 /* PWM event line 0 */
+#define ADC_MR_TRGSEL_TRIG5 5 /* PWM event line 1 */
+#define ADC_MR_TRGSEL_TRIG6 6 /* TIOA3 */
+#define ADC_MR_TRGSEL_TRIG7 7 /* RTCOUT0 */
+#define ADC_MR_SLEEP BIT(5) /* Sleep Mode */
+#define ADC_MR_FWUP BIT(6) /* Fast Wake Up */
+#define ADC_MR_PRESCAL(v) (v << 8) /* Prescaler Rate Selection */
+#define ADC_MR_PRESCAL_MAX 0xffff
+#define ADC_MR_STARTUP(v) (v << 16) /* Startup Time */
+#define ADC_MR_STARTUP_SUT0 0 /* 0 period of ADCCLK */
+#define ADC_MR_STARTUP_SUT8 1 /* 8 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT16 2 /* 16 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT24 3 /* 24 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT64 4 /* 64 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT80 5 /* 80 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT96 6 /* 96 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT112 7 /* 112 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT512 8 /* 512 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT576 9 /* 576 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT640 10 /* 640 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT704 11 /* 704 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT768 12 /* 768 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT832 13 /* 832 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT896 14 /* 896 periods of ADCCLK */
+#define ADC_MR_STARTUP_SUT960 15 /* 960 periods of ADCCLK */
+#define ADC_MR_ANACH BIT(23) /* Analog Change */
+#define ADC_MR_TRACKTIM(v) (v << 24) /* Tracking Time */
+#define ADC_MR_TRACKTIM_MAX 0xff
+#define ADC_MR_TRANSFER(v) (v << 28) /* Transfer Time */
+#define ADC_MR_TRANSFER_MAX 0x3
+#define ADC_MR_USEQ BIT(31) /* Use Sequence Enable */
+#define ADC_SEQR1 0x08 /* Channel Sequence Register 1 */
+#define ADC_SEQR2 0x0c /* Channel Sequence Register 2 */
+#define ADC_CHER 0x10 /* Channel Enable Register */
+#define ADC_CHDR 0x14 /* Channel Disable Register */
+#define ADC_CHSR 0x18 /* Channel Status Register */
+#define ADC_LCDR 0x20 /* Last Converted Data Register */
+#define ADC_IER 0x24 /* Interrupt Enable Register */
+#define ADC_IDR 0x28 /* Interrupt Disable Register */
+#define ADC_IMR 0x2c /* Interrupt Mask Register */
+#define ADC_ISR 0x30 /* Interrupt Status Register */
+#define ADC_LCTMR 0x34 /* Last Channel Trigger Mode Register */
+#define ADC_LCCWR 0x38 /* Last Channel Compare Window Register */
+#define ADC_OVER 0x3c /* Overrun Status Register */
+#define ADC_EMR 0x40 /* Extended Mode Register */
+#define ADC_CWR 0x44 /* Compare Window Register */
+#define ADC_CGR 0x48 /* Channel Gain Register */
+#define ADC_COR 0x4c /* Channel Offset Register */
+#define ADC_CDR0 0x50 /* Channel Data Register 0 */
+#define ADC_ACR 0x94 /* Analog Control Register */
+#define ADC_TSMR 0xb0 /* Touchscreen Mode Register */
+#define ADC_XPOSR 0xb4 /* Touchscreen X Position Register */
+#define ADC_YPOSR 0xb8 /* Touchscreen Y Position Register */
+#define ADC_PRESSR 0xbc /* Touchscreen Pressure Register */
+#define ADC_TRGR 0xc0 /* Trigger Register */
+#define ADC_COSR 0xd0 /* Correction Select Register */
+#define ADC_CVR 0xd4 /* Correction Value Register */
+#define ADC_CECR 0xd8 /* Channel Error Correction Register */
+#define ADC_WPMR 0xe4 /* Write Protection Mode Register */
+#define ADC_WPSR 0xe8 /* Write Protection Status Register */
+#define ADC_VERSION 0xfc /* Version Register */
+
+#define AT91_ADC_CHAN(num, addr) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .channel = num, \
+ .address = addr, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 12, \
+ .storagebits = 14, \
+ }, \
+ .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_f_adc;
+ unsigned max_f_adc;
+ const struct iio_chan_spec *channels;
+ int num_channels;
+};
+
+struct at91_adc_state {
+ void __iomem *base;
+ struct clk *per_clk;
+ struct clk *adc_clk;
+ int irq;
+ struct regulator *reg;
+ struct regulator *vref;
+ u32 vref_uv;
+ struct at91_adc_soc_info *soc_info;
+ wait_queue_head_t wq_data_available;
+ bool done;
+ const struct iio_chan_spec *chan;
+ u32 last_value;
+ struct mutex lock;
+};
+
+static struct at91_adc_soc_info at91_adc_sama5d2_soc_info = {
+ .startup_time = 4,
+ .min_f_adc = 200000,
+ .max_f_adc = 20000000,
+};
+
+static const struct iio_chan_spec at91_adc_channels[] = {
+ AT91_ADC_CHAN(0, 0x50),
+ AT91_ADC_CHAN(1, 0x54),
+ AT91_ADC_CHAN(2, 0x58),
+ AT91_ADC_CHAN(3, 0x5c),
+ AT91_ADC_CHAN(4, 0x60),
+ AT91_ADC_CHAN(5, 0x64),
+ AT91_ADC_CHAN(6, 0x68),
+ AT91_ADC_CHAN(7, 0x6c),
+ AT91_ADC_CHAN(8, 0x70),
+ AT91_ADC_CHAN(9, 0x74),
+ AT91_ADC_CHAN(10, 0x78),
+ AT91_ADC_CHAN(11, 0x7c),
+};
+
+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, ADC_ISR);
+
+ status &= at91_adc_readl(st, ADC_IMR);
+ if (status & 0xFFF) {
+ st->last_value = at91_adc_readl(st, st->chan->address);
+ st->done = true;
+ wake_up_interruptible(&st->wq_data_available);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static bool at91_adc_freq_supported(struct at91_adc_state *st, unsigned freq)
+{
+ return ((freq >= st->soc_info->min_f_adc)
+ && (freq <= st->soc_info->max_f_adc));
+}
+
+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 int at91_adc_init(struct at91_adc_state *st)
+{
+ struct iio_dev *indio_dev = iio_priv_to_dev(st);
+ unsigned f_adc, f_per, prescal, startup;
+
+ at91_adc_writel(st, ADC_CR, ADC_CR_SWRST);
+ at91_adc_writel(st, ADC_IDR, 0xffffffff);
+
+ f_adc = clk_get_rate(st->adc_clk);
+ if (!at91_adc_freq_supported(st, f_adc)) {
+ dev_err(&indio_dev->dev, "unsupported adc clock frequency\n");
+ return -EINVAL;
+ }
+
+ f_per = clk_get_rate(st->per_clk);
+ prescal = (f_per / (2 * f_adc)) - 1;
+
+ startup = at91_adc_startup_time(st->soc_info->startup_time,
+ f_adc / 1000);
+
+ at91_adc_writel(st, ADC_MR,
+ ADC_MR_TRANSFER(2)
+ | ADC_MR_STARTUP(startup)
+ | ADC_MR_PRESCAL(prescal));
+
+ dev_dbg(&indio_dev->dev, "startup: %u, prescal: %u\n",
+ startup, prescal);
+
+ return 0;
+}
+
+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;
+
+ st->chan = chan;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&st->lock);
+
+ at91_adc_writel(st, ADC_CHER, BIT(chan->channel));
+ at91_adc_writel(st, ADC_IER, BIT(chan->channel));
+ at91_adc_writel(st, ADC_CR, ADC_CR_START);
+
+ ret = wait_event_interruptible_timeout(st->wq_data_available,
+ st->done,
+ msecs_to_jiffies(1000));
+ if (ret == 0)
+ ret = -ETIMEDOUT;
+
+ if (ret <= 0) {
+ at91_adc_writel(st, ADC_CHDR, BIT(chan->channel));
+ at91_adc_writel(st, ADC_IDR, BIT(chan->channel));
+ mutex_unlock(&st->lock);
+ return ret;
+ }
+
+ if (chan->scan_type.sign == 's')
+ *val = sign_extend32(st->last_value,
+ chan->scan_type.realbits - 1);
+ else
+ *val = st->last_value;
+ at91_adc_writel(st, ADC_CHDR, BIT(chan->channel));
+ at91_adc_writel(st, ADC_IDR, BIT(chan->channel));
+ st->done = false;
+
+ mutex_unlock(&st->lock);
+ return IIO_VAL_INT;
+
+ 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,
+};
+
+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);
+ st->soc_info = (struct at91_adc_soc_info *)
+ of_device_get_match_data(&pdev->dev);
+ 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)
+ 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->adc_clk = devm_clk_get(&pdev->dev, "adc_op_clk");
+ if (IS_ERR(st->adc_clk))
+ return PTR_ERR(st->adc_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;
+
+ st->vref_uv = regulator_get_voltage(st->vref);
+ if (st->vref_uv <= 0) {
+ ret = -EINVAL;
+ goto error;
+ }
+
+ ret = at91_adc_init(st);
+ if (ret)
+ goto error;
+
+ ret = clk_prepare_enable(st->adc_clk);
+ ret = clk_prepare_enable(st->per_clk);
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0)
+ return ret;
+
+ dev_info(&pdev->dev, "version: %x\n",
+ readl_relaxed(st->base + ADC_VERSION));
+
+error:
+ 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);
+ clk_disable_unprepare(st->adc_clk);
+
+ return 0;
+}
+
+static const struct of_device_id at91_adc_dt_match[] = {
+ {
+ .compatible = "atmel,sama5d2-adc",
+ .data = &at91_adc_sama5d2_soc_info
+ }, {
+ /* 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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