diff options
Diffstat (limited to 'drivers/iio/adc/at91-sama5d2_adc.c')
-rw-r--r-- | drivers/iio/adc/at91-sama5d2_adc.c | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c new file mode 100644 index 0000000..dbee13a --- /dev/null +++ b/drivers/iio/adc/at91-sama5d2_adc.c @@ -0,0 +1,508 @@ +/* + * Atmel ADC driver for SAMA5D2 devices and compatible. + * + * 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/iio/sysfs.h> +#include <linux/regulator/consumer.h> + +/* Control Register */ +#define AT91_SAMA5D2_CR 0x00 +/* Software Reset */ +#define AT91_SAMA5D2_CR_SWRST BIT(0) +/* Start Conversion */ +#define AT91_SAMA5D2_CR_START BIT(1) +/* Touchscreen Calibration */ +#define AT91_SAMA5D2_CR_TSCALIB BIT(2) +/* Comparison Restart */ +#define AT91_SAMA5D2_CR_CMPRST BIT(4) + +/* Mode Register */ +#define AT91_SAMA5D2_MR 0x04 +/* Trigger Selection */ +#define AT91_SAMA5D2_MR_TRGSEL(v) ((v) << 1) +/* ADTRG */ +#define AT91_SAMA5D2_MR_TRGSEL_TRIG0 0 +/* TIOA0 */ +#define AT91_SAMA5D2_MR_TRGSEL_TRIG1 1 +/* TIOA1 */ +#define AT91_SAMA5D2_MR_TRGSEL_TRIG2 2 +/* TIOA2 */ +#define AT91_SAMA5D2_MR_TRGSEL_TRIG3 3 +/* PWM event line 0 */ +#define AT91_SAMA5D2_MR_TRGSEL_TRIG4 4 +/* PWM event line 1 */ +#define AT91_SAMA5D2_MR_TRGSEL_TRIG5 5 +/* TIOA3 */ +#define AT91_SAMA5D2_MR_TRGSEL_TRIG6 6 +/* RTCOUT0 */ +#define AT91_SAMA5D2_MR_TRGSEL_TRIG7 7 +/* Sleep Mode */ +#define AT91_SAMA5D2_MR_SLEEP BIT(5) +/* Fast Wake Up */ +#define AT91_SAMA5D2_MR_FWUP BIT(6) +/* Prescaler Rate Selection */ +#define AT91_SAMA5D2_MR_PRESCAL(v) ((v) << AT91_SAMA5D2_MR_PRESCAL_OFFSET) +#define AT91_SAMA5D2_MR_PRESCAL_OFFSET 8 +#define AT91_SAMA5D2_MR_PRESCAL_MAX 0xff +/* Startup Time */ +#define AT91_SAMA5D2_MR_STARTUP(v) ((v) << 16) +/* Analog Change */ +#define AT91_SAMA5D2_MR_ANACH BIT(23) +/* Tracking Time */ +#define AT91_SAMA5D2_MR_TRACKTIM(v) ((v) << 24) +#define AT91_SAMA5D2_MR_TRACKTIM_MAX 0xff +/* Transfer Time */ +#define AT91_SAMA5D2_MR_TRANSFER(v) ((v) << 28) +#define AT91_SAMA5D2_MR_TRANSFER_MAX 0x3 +/* Use Sequence Enable */ +#define AT91_SAMA5D2_MR_USEQ BIT(31) + +/* Channel Sequence Register 1 */ +#define AT91_SAMA5D2_SEQR1 0x08 +/* Channel Sequence Register 2 */ +#define AT91_SAMA5D2_SEQR2 0x0c +/* Channel Enable Register */ +#define AT91_SAMA5D2_CHER 0x10 +/* Channel Disable Register */ +#define AT91_SAMA5D2_CHDR 0x14 +/* Channel Status Register */ +#define AT91_SAMA5D2_CHSR 0x18 +/* Last Converted Data Register */ +#define AT91_SAMA5D2_LCDR 0x20 +/* Interrupt Enable Register */ +#define AT91_SAMA5D2_IER 0x24 +/* Interrupt Disable Register */ +#define AT91_SAMA5D2_IDR 0x28 +/* Interrupt Mask Register */ +#define AT91_SAMA5D2_IMR 0x2c +/* Interrupt Status Register */ +#define AT91_SAMA5D2_ISR 0x30 +/* Last Channel Trigger Mode Register */ +#define AT91_SAMA5D2_LCTMR 0x34 +/* Last Channel Compare Window Register */ +#define AT91_SAMA5D2_LCCWR 0x38 +/* Overrun Status Register */ +#define AT91_SAMA5D2_OVER 0x3c +/* Extended Mode Register */ +#define AT91_SAMA5D2_EMR 0x40 +/* Compare Window Register */ +#define AT91_SAMA5D2_CWR 0x44 +/* Channel Gain Register */ +#define AT91_SAMA5D2_CGR 0x48 +/* Channel Offset Register */ +#define AT91_SAMA5D2_COR 0x4c +/* Channel Data Register 0 */ +#define AT91_SAMA5D2_CDR0 0x50 +/* Analog Control Register */ +#define AT91_SAMA5D2_ACR 0x94 +/* Touchscreen Mode Register */ +#define AT91_SAMA5D2_TSMR 0xb0 +/* Touchscreen X Position Register */ +#define AT91_SAMA5D2_XPOSR 0xb4 +/* Touchscreen Y Position Register */ +#define AT91_SAMA5D2_YPOSR 0xb8 +/* Touchscreen Pressure Register */ +#define AT91_SAMA5D2_PRESSR 0xbc +/* Trigger Register */ +#define AT91_SAMA5D2_TRGR 0xc0 +/* Correction Select Register */ +#define AT91_SAMA5D2_COSR 0xd0 +/* Correction Value Register */ +#define AT91_SAMA5D2_CVR 0xd4 +/* Channel Error Correction Register */ +#define AT91_SAMA5D2_CECR 0xd8 +/* Write Protection Mode Register */ +#define AT91_SAMA5D2_WPMR 0xe4 +/* Write Protection Status Register */ +#define AT91_SAMA5D2_WPSR 0xe8 +/* Version Register */ +#define AT91_SAMA5D2_VERSION 0xfc + +#define AT91_AT91_SAMA5D2_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), \ + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\ + .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; + int 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; + /* + * lock to prevent concurrent 'single conversion' requests through + * sysfs. + */ + struct mutex lock; +}; + +static const struct iio_chan_spec at91_adc_channels[] = { + AT91_AT91_SAMA5D2_CHAN(0, 0x50), + AT91_AT91_SAMA5D2_CHAN(1, 0x54), + AT91_AT91_SAMA5D2_CHAN(2, 0x58), + AT91_AT91_SAMA5D2_CHAN(3, 0x5c), + AT91_AT91_SAMA5D2_CHAN(4, 0x60), + AT91_AT91_SAMA5D2_CHAN(5, 0x64), + AT91_AT91_SAMA5D2_CHAN(6, 0x68), + AT91_AT91_SAMA5D2_CHAN(7, 0x6c), + AT91_AT91_SAMA5D2_CHAN(8, 0x70), + AT91_AT91_SAMA5D2_CHAN(9, 0x74), + AT91_AT91_SAMA5D2_CHAN(10, 0x78), + AT91_AT91_SAMA5D2_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_SAMA5D2_MR, + AT91_SAMA5D2_MR_TRANSFER(2) + | AT91_SAMA5D2_MR_STARTUP(startup) + | AT91_SAMA5D2_MR_PRESCAL(prescal)); + + dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n", + freq, startup, prescal); +} + +static unsigned at91_adc_get_sample_freq(struct at91_adc_state *st) +{ + unsigned f_adc, f_per = clk_get_rate(st->per_clk); + unsigned mr, prescal; + + mr = at91_adc_readl(st, AT91_SAMA5D2_MR); + prescal = (mr >> AT91_SAMA5D2_MR_PRESCAL_OFFSET) + & AT91_SAMA5D2_MR_PRESCAL_MAX; + f_adc = f_per / (2 * (prescal + 1)); + + return f_adc; +} + +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_SAMA5D2_ISR); + u32 imr = at91_adc_readl(st, AT91_SAMA5D2_IMR); + + if (status & imr) { + st->conversion_value = at91_adc_readl(st, st->chan->address); + st->conversion_done = true; + wake_up_interruptible(&st->wq_data_available); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +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_SAMA5D2_CHER, BIT(chan->channel)); + at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel)); + at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_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_SAMA5D2_IDR, BIT(chan->channel)); + at91_adc_writel(st, AT91_SAMA5D2_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; + + case IIO_CHAN_INFO_SAMP_FREQ: + *val = at91_adc_get_sample_freq(st); + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static int at91_adc_write_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); + + if (mask != IIO_CHAN_INFO_SAMP_FREQ) + 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 0; +} + +static const struct iio_info at91_adc_info = { + .read_raw = &at91_adc_read_raw, + .write_raw = &at91_adc_write_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(*st)); + 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-hz", + &st->soc_info.min_sample_rate); + if (ret) { + dev_err(&pdev->dev, + "invalid or missing value for atmel,min-sample-rate-hz\n"); + return ret; + } + + ret = of_property_read_u32(pdev->dev.of_node, + "atmel,max-sample-rate-hz", + &st->soc_info.max_sample_rate); + if (ret) { + dev_err(&pdev->dev, + "invalid or missing value for atmel,max-sample-rate-hz\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_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST); + at91_adc_writel(st, AT91_SAMA5D2_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_SAMA5D2_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-sama5d2_adc", + .of_match_table = at91_adc_dt_match, + }, +}; +module_platform_driver(at91_adc_driver) + +MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>"); +MODULE_DESCRIPTION("Atmel AT91 SAMA5D2 ADC"); +MODULE_LICENSE("GPL v2"); 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