--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Analog Devices AD9739a SPI DAC driver
+ *
+ * Copyright 2015-2024 Analog Devices Inc.
+ */
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/gpio/consumer.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/units.h>
+
+#include <linux/iio/backend.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/types.h>
+
+#define AD9739A_REG_MODE 0
+#define AD9739A_RESET_MASK BIT(5)
+#define AD9739A_REG_FSC_1 0x06
+#define AD9739A_REG_FSC_2 0x07
+#define AD9739A_FSC_MSB GENMASK(1, 0)
+#define AD9739A_REG_DEC_CNT 0x8
+#define AD9739A_NORMAL_MODE 0
+#define AD9739A_MIXED_MODE 2
+#define AD9739A_DAC_DEC GENMASK(1, 0)
+#define AD9739A_REG_LVDS_REC_CNT1 0x10
+#define AD9739A_RCVR_LOOP_EN_MASK GENMASK(1, 0)
+#define AD9739A_REG_LVDS_REC_CNT4 0x13
+#define AD9739A_FINE_DEL_SKW_MASK GENMASK(3, 0)
+#define AD9739A_REG_LVDS_REC_STAT9 0x21
+#define AD9739A_RCVR_TRACK_AND_LOCK (BIT(3) | BIT(0))
+#define AD9739A_REG_CROSS_CNT1 0x22
+#define AD9739A_REG_CROSS_CNT2 0x23
+#define AD9739A_REG_PHS_DET 0x24
+#define AD9739A_REG_MU_DUTY 0x25
+#define AD9739A_REG_MU_CNT1 0x26
+#define AD9739A_MU_EN_MASK BIT(0)
+#define AD9739A_REG_MU_CNT2 0x27
+#define AD9739A_REG_MU_CNT3 0x28
+#define AD9739A_REG_MU_CNT4 0x29
+#define AD9739A_MU_CNT4_DEFAULT 0xcb
+#define AD9739A_REG_MU_STAT1 0x2A
+#define AD9739A_MU_LOCK_MASK BIT(0)
+#define AD9739A_REG_ANA_CNT_1 0x32
+#define AD9739A_REG_ID 0x35
+
+#define AD9739A_ID 0x24
+#define AD9739A_REG_IS_RESERVED(reg) \
+ ((reg) == 0x5 || (reg) == 0x9 || (reg) == 0x0E || (reg) == 0x0D || \
+ (reg) == 0x2B || (reg) == 0x2C || (reg) == 0x34)
+
+#define AD9739A_FSC_MIN 8580
+#define AD9739A_FSC_MAX 31700
+#define AD9739A_FSC_RANGE (AD9739A_FSC_MAX - AD9739A_FSC_MIN + 1)
+
+#define AD9739A_MIN_DAC_CLK (1600 * MEGA)
+#define AD9739A_MAX_DAC_CLK (2500 * MEGA)
+#define AD9739A_DAC_CLK_RANGE (AD9739A_MAX_DAC_CLK - AD9739A_MIN_DAC_CLK + 1)
+/* as recommended by the datasheet */
+#define AD9739A_LOCK_N_TRIES 3
+
+struct ad9739a_state {
+ struct iio_backend *back;
+ struct regmap *regmap;
+ unsigned long sample_rate;
+};
+
+static int ad9739a_oper_mode_get(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct ad9739a_state *st = iio_priv(indio_dev);
+ u32 mode;
+ int ret;
+
+ ret = regmap_read(st->regmap, AD9739A_REG_DEC_CNT, &mode);
+ if (ret)
+ return ret;
+
+ mode = FIELD_GET(AD9739A_DAC_DEC, mode);
+ /* sanity check we get valid values from the HW */
+ if (mode != AD9739A_NORMAL_MODE && mode != AD9739A_MIXED_MODE)
+ return -EIO;
+ if (!mode)
+ return AD9739A_NORMAL_MODE;
+
+ /*
+ * We get 2 from the device but for IIO modes, that means 1. Hence the
+ * minus 1.
+ */
+ return AD9739A_MIXED_MODE - 1;
+}
+
+static int ad9739a_oper_mode_set(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, u32 mode)
+{
+ struct ad9739a_state *st = iio_priv(indio_dev);
+
+ /*
+ * On the IIO interface we have 0 and 1 for mode. But for mixed_mode, we
+ * need to write 2 in the device. That's what the below check is about.
+ */
+ if (mode == AD9739A_MIXED_MODE - 1)
+ mode = AD9739A_MIXED_MODE;
+
+ return regmap_update_bits(st->regmap, AD9739A_REG_DEC_CNT,
+ AD9739A_DAC_DEC, mode);
+}
+
+static int ad9739a_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct ad9739a_state *st = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = st->sample_rate;
+ *val2 = 0;
+ return IIO_VAL_INT_64;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ad9739a_buffer_preenable(struct iio_dev *indio_dev)
+{
+ struct ad9739a_state *st = iio_priv(indio_dev);
+
+ return iio_backend_data_source_set(st->back, 0, IIO_BACKEND_EXTERNAL);
+}
+
+static int ad9739a_buffer_postdisable(struct iio_dev *indio_dev)
+{
+ struct ad9739a_state *st = iio_priv(indio_dev);
+
+ return iio_backend_data_source_set(st->back, 0,
+ IIO_BACKEND_INTERNAL_CONTINUOS_WAVE);
+}
+
+static bool ad9739a_reg_accessible(struct device *dev, unsigned int reg)
+{
+ if (AD9739A_REG_IS_RESERVED(reg))
+ return false;
+ if (reg > AD9739A_REG_MU_STAT1 && reg < AD9739A_REG_ANA_CNT_1)
+ return false;
+
+ return true;
+}
+
+static int ad9739a_reset(struct device *dev, const struct ad9739a_state *st)
+{
+ struct gpio_desc *gpio;
+ int ret;
+
+ gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(gpio))
+ return PTR_ERR(gpio);
+ if (gpio) {
+ /* minimum pulse width of 40ns */
+ ndelay(40);
+ gpiod_set_value_cansleep(gpio, 0);
+ return 0;
+ }
+
+ /* bring all registers to their default state */
+ ret = regmap_set_bits(st->regmap, AD9739A_REG_MODE, AD9739A_RESET_MASK);
+ if (ret)
+ return ret;
+
+ ndelay(40);
+
+ return regmap_clear_bits(st->regmap, AD9739A_REG_MODE,
+ AD9739A_RESET_MASK);
+}
+
+/*
+ * Recommended values (as per datasheet) for the dac clk common mode voltage
+ * and Mu controller. Look at table 29.
+ */
+static const struct reg_sequence ad9739a_clk_mu_ctrl[] = {
+ /* DAC clk common mode voltage */
+ { AD9739A_REG_CROSS_CNT1, 0x0f },
+ { AD9739A_REG_CROSS_CNT2, 0x0f },
+ /* Mu controller configuration */
+ { AD9739A_REG_PHS_DET, 0x30 },
+ { AD9739A_REG_MU_DUTY, 0x80 },
+ { AD9739A_REG_MU_CNT2, 0x44 },
+ { AD9739A_REG_MU_CNT3, 0x6c },
+};
+
+static int ad9739a_init(struct device *dev, const struct ad9739a_state *st)
+{
+ unsigned int i = 0, lock, fsc;
+ u32 fsc_raw;
+ int ret;
+
+ ret = regmap_multi_reg_write(st->regmap, ad9739a_clk_mu_ctrl,
+ ARRAY_SIZE(ad9739a_clk_mu_ctrl));
+ if (ret)
+ return ret;
+
+ /*
+ * Try to get the Mu lock. Repeat the below steps AD9739A_LOCK_N_TRIES
+ * (as specified by the datasheet) until we get the lock.
+ */
+ do {
+ ret = regmap_write(st->regmap, AD9739A_REG_MU_CNT4,
+ AD9739A_MU_CNT4_DEFAULT);
+ if (ret)
+ return ret;
+
+ /* Enable the Mu controller search and track mode. */
+ ret = regmap_set_bits(st->regmap, AD9739A_REG_MU_CNT1,
+ AD9739A_MU_EN_MASK);
+ if (ret)
+ return ret;
+
+ /* Ensure the DLL loop is locked */
+ ret = regmap_read_poll_timeout(st->regmap, AD9739A_REG_MU_STAT1,
+ lock, lock & AD9739A_MU_LOCK_MASK,
+ 0, 1000);
+ if (ret && ret != -ETIMEDOUT)
+ return ret;
+ } while (ret && ++i < AD9739A_LOCK_N_TRIES);
+
+ if (i == AD9739A_LOCK_N_TRIES)
+ return dev_err_probe(dev, ret, "Mu lock timeout\n");
+
+ /* Receiver tracking and lock. Same deal as the Mu controller */
+ i = 0;
+ do {
+ ret = regmap_update_bits(st->regmap, AD9739A_REG_LVDS_REC_CNT4,
+ AD9739A_FINE_DEL_SKW_MASK,
+ FIELD_PREP(AD9739A_FINE_DEL_SKW_MASK, 2));
+ if (ret)
+ return ret;
+
+ /* Disable the receiver and the loop. */
+ ret = regmap_write(st->regmap, AD9739A_REG_LVDS_REC_CNT1, 0);
+ if (ret)
+ return ret;
+
+ /*
+ * Re-enable the loop so it falls out of lock and begins the
+ * search/track routine again.
+ */
+ ret = regmap_set_bits(st->regmap, AD9739A_REG_LVDS_REC_CNT1,
+ AD9739A_RCVR_LOOP_EN_MASK);
+ if (ret)
+ return ret;
+
+ /* Ensure the DLL loop is locked */
+ ret = regmap_read_poll_timeout(st->regmap,
+ AD9739A_REG_LVDS_REC_STAT9, lock,
+ lock == AD9739A_RCVR_TRACK_AND_LOCK,
+ 0, 1000);
+ if (ret && ret != -ETIMEDOUT)
+ return ret;
+ } while (ret && ++i < AD9739A_LOCK_N_TRIES);
+
+ if (i == AD9739A_LOCK_N_TRIES)
+ return dev_err_probe(dev, ret, "Receiver lock timeout\n");
+
+ ret = device_property_read_u32(dev, "adi,full-scale-microamp", &fsc);
+ if (ret && ret == -EINVAL)
+ return 0;
+ if (ret)
+ return ret;
+ if (!in_range(fsc, AD9739A_FSC_MIN, AD9739A_FSC_RANGE))
+ return dev_err_probe(dev, -EINVAL,
+ "Invalid full scale current(%u) [%u %u]\n",
+ fsc, AD9739A_FSC_MIN, AD9739A_FSC_MAX);
+ /*
+ * IOUTFS is given by
+ * Ioutfs = 0.0226 * FSC + 8.58
+ * and is given in mA. Hence we'll have to multiply by 10 * MILLI in
+ * order to get rid of the fractional.
+ */
+ fsc_raw = DIV_ROUND_CLOSEST(fsc * 10 - 85800, 226);
+
+ ret = regmap_write(st->regmap, AD9739A_REG_FSC_1, fsc_raw & 0xff);
+ if (ret)
+ return ret;
+
+ return regmap_update_bits(st->regmap, AD9739A_REG_FSC_2,
+ AD9739A_FSC_MSB, fsc_raw >> 8);
+}
+
+static const char * const ad9739a_modes_avail[] = { "normal", "mixed-mode" };
+
+static const struct iio_enum ad9739a_modes = {
+ .items = ad9739a_modes_avail,
+ .num_items = ARRAY_SIZE(ad9739a_modes_avail),
+ .get = ad9739a_oper_mode_get,
+ .set = ad9739a_oper_mode_set,
+};
+
+static const struct iio_chan_spec_ext_info ad9739a_ext_info[] = {
+ IIO_ENUM_AVAILABLE("operating_mode", IIO_SEPARATE, &ad9739a_modes),
+ IIO_ENUM("operating_mode", IIO_SEPARATE, &ad9739a_modes),
+ { }
+};
+
+/*
+ * The reason for having two different channels is because we have, in reality,
+ * two sources of data:
+ * ALTVOLTAGE: It's a Continuous Wave that's internally generated by the
+ * backend device.
+ * VOLTAGE: It's the typical data we can have in a DAC device and the source
+ * of it has nothing to do with the backend. The backend will only
+ * forward it into our data interface to be sent out.
+ */
+static struct iio_chan_spec ad9739a_channels[] = {
+ {
+ .type = IIO_ALTVOLTAGE,
+ .indexed = 1,
+ .output = 1,
+ .scan_index = -1,
+ },
+ {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ .output = 1,
+ .ext_info = ad9739a_ext_info,
+ .scan_type = {
+ .sign = 's',
+ .storagebits = 16,
+ .realbits = 16,
+ },
+ }
+};
+
+static const struct iio_info ad9739a_info = {
+ .read_raw = ad9739a_read_raw,
+};
+
+static const struct iio_buffer_setup_ops ad9739a_buffer_setup_ops = {
+ .preenable = &ad9739a_buffer_preenable,
+ .postdisable = &ad9739a_buffer_postdisable,
+};
+
+static const struct regmap_config ad9739a_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .readable_reg = ad9739a_reg_accessible,
+ .writeable_reg = ad9739a_reg_accessible,
+ .max_register = AD9739A_REG_ID,
+};
+
+static int ad9739a_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ struct iio_dev *indio_dev;
+ struct ad9739a_state *st;
+ unsigned int id;
+ struct clk *clk;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+
+ clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(clk))
+ return dev_err_probe(dev, PTR_ERR(clk), "Could not get clkin\n");
+
+ st->sample_rate = clk_get_rate(clk);
+ if (!in_range(st->sample_rate, AD9739A_MIN_DAC_CLK,
+ AD9739A_DAC_CLK_RANGE))
+ return dev_err_probe(dev, -EINVAL,
+ "Invalid dac clk range(%lu) [%lu %lu]\n",
+ st->sample_rate, AD9739A_MIN_DAC_CLK,
+ AD9739A_MAX_DAC_CLK);
+
+ st->regmap = devm_regmap_init_spi(spi, &ad9739a_regmap_config);
+ if (IS_ERR(st->regmap))
+ return PTR_ERR(st->regmap);
+
+ ret = regmap_read(st->regmap, AD9739A_REG_ID, &id);
+ if (ret)
+ return ret;
+
+ if (id != AD9739A_ID)
+ dev_warn(dev, "Unrecognized CHIP_ID 0x%X", id);
+
+ ret = ad9739a_reset(dev, st);
+ if (ret)
+ return ret;
+
+ ret = ad9739a_init(dev, st);
+ if (ret)
+ return ret;
+
+ st->back = devm_iio_backend_get(dev, NULL);
+ if (IS_ERR(st->back))
+ return PTR_ERR(st->back);
+
+ ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev);
+ if (ret)
+ return ret;
+
+ ret = iio_backend_extend_chan_spec(indio_dev, st->back,
+ &ad9739a_channels[0]);
+ if (ret)
+ return ret;
+
+ ret = iio_backend_set_sampling_freq(st->back, 0, st->sample_rate);
+ if (ret)
+ return ret;
+
+ ret = devm_iio_backend_enable(dev, st->back);
+ if (ret)
+ return ret;
+
+ indio_dev->name = "ad9739a";
+ indio_dev->info = &ad9739a_info;
+ indio_dev->channels = ad9739a_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ad9739a_channels);
+ indio_dev->setup_ops = &ad9739a_buffer_setup_ops;
+
+ return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct of_device_id ad9739a_of_match[] = {
+ { .compatible = "adi,ad9739a" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, ad9739a_of_match);
+
+static const struct spi_device_id ad9739a_id[] = {
+ {"ad9739a"},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, ad9739a_id);
+
+static struct spi_driver ad9739a_driver = {
+ .driver = {
+ .name = "ad9739a",
+ .of_match_table = ad9739a_of_match,
+ },
+ .probe = ad9739a_probe,
+ .id_table = ad9739a_id,
+};
+module_spi_driver(ad9739a_driver);
+
+MODULE_DESCRIPTION("Analog Devices AD9739 DAC");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(IIO_BACKEND);
projects / J-linux.git / commitdiff