[PATCH 1/5] iio:adc:at91_adc8xx: introduce new atmel adc driver
From: jic23@kernel.org (Jonathan Cameron)
Date: 2015-12-22 18:34:08
Also in:
linux-devicetree, linux-iio, lkml
On 21/12/15 09:24, Ludovic Desroches wrote:
This driver supports the new version of the Atmel ADC device introduced with the SAMA5D2 SoC family. Signed-off-by: Ludovic Desroches <redacted>
A few more bits and bobs from me. Mostly looking good. Jonathan
quoted hunk ↗ jump to hunk
--- .../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.cdiff --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 at 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_AXP20Xdiff --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.odiff --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@atmel.com> + * + * 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,
These rather look like things that should be in the device tree if they are going to change between SoC varients.
+};
+
+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);If this is a polled read - is there any reason to read this value here rather than outside the interrupt?
+ 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)could be be 0 (effectively marked as not present) - probably want to check for that and fault out if so.
+ 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);
You get this regulator but never explicitly request that it is on... I can understand that for a reference like below (though probably want to turn that on as well really).
+
+ 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);Handle these possible errors.
+ 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 [off-list ref]");
+MODULE_DESCRIPTION("Atmel AT91 ADC 8xx");
+MODULE_LICENSE("GPL v2");