iio: frequency: New driver for Analog Devices ADF4350/ADF4351 Wideband Synthesizers

Changes since V1:
Apply Jonathan's review feedback:
    Introduce and use IIO_ALTVOLTAGE.
    Fix up comments and documentation.
    Remove dead code.
    Reorder some code fragments.
    Add missing iio_device_free.

Convert to new API.
Fix-up out of staging includes.
Removed pll_locked attribute.

Changes since V2:
Use module_spi_driver.
adf4350_remove: move gpio_free after regulator.
target patch to drivers/iio

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 497 insertions, 0 deletions

diff --git a/drivers/iio/frequency/Kconfig b/drivers/iio/frequency/Kconfig
index 0458c92464a..6aaa33ef454 100644
--- a/drivers/iio/frequency/Kconfig
+++ b/drivers/iio/frequency/Kconfig
@@ -20,4 +20,22 @@ config AD9523
 	  module will be called ad9523.
 
 endmenu
+
+#
+# Phase-Locked Loop (PLL) frequency synthesizers
+#
+
+menu "Phase-Locked Loop (PLL) frequency synthesizers"
+
+config ADF4350
+	tristate "Analog Devices ADF4350/ADF4351 Wideband Synthesizers"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices  ADF4350/ADF4351
+	  Wideband Synthesizers. The driver provides direct access via sysfs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called adf4350.
+
+endmenu
 endmenu
diff --git a/drivers/iio/frequency/Makefile b/drivers/iio/frequency/Makefile
index 1b5b22417da..00d26e5d1dc 100644
--- a/drivers/iio/frequency/Makefile
+++ b/drivers/iio/frequency/Makefile
@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_AD9523) += ad9523.o
+obj-$(CONFIG_ADF4350) += adf4350.o
diff --git a/drivers/iio/frequency/adf4350.c b/drivers/iio/frequency/adf4350.c
new file mode 100644
index 00000000000..fd4c8501aba
--- /dev/null
+++ b/drivers/iio/frequency/adf4350.c
@@ -0,0 +1,478 @@
+/*
+ * ADF4350/ADF4351 SPI Wideband Synthesizer driver
+ *
+ * Copyright 2012 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/spi/spi.h>
+#include <linux/regulator/consumer.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/gcd.h>
+#include <linux/gpio.h>
+#include <asm/div64.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/frequency/adf4350.h>
+
+enum {
+	ADF4350_FREQ,
+	ADF4350_FREQ_REFIN,
+	ADF4350_FREQ_RESOLUTION,
+	ADF4350_PWRDOWN,
+};
+
+struct adf4350_state {
+	struct spi_device		*spi;
+	struct regulator		*reg;
+	struct adf4350_platform_data	*pdata;
+	unsigned long			clkin;
+	unsigned long			chspc; /* Channel Spacing */
+	unsigned long			fpfd; /* Phase Frequency Detector */
+	unsigned long			min_out_freq;
+	unsigned			r0_fract;
+	unsigned			r0_int;
+	unsigned			r1_mod;
+	unsigned			r4_rf_div_sel;
+	unsigned long			regs[6];
+	unsigned long			regs_hw[6];
+
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	__be32				val ____cacheline_aligned;
+};
+
+static struct adf4350_platform_data default_pdata = {
+	.clkin = 122880000,
+	.channel_spacing = 10000,
+	.r2_user_settings = ADF4350_REG2_PD_POLARITY_POS,
+			    ADF4350_REG2_CHARGE_PUMP_CURR_uA(2500),
+	.r3_user_settings = ADF4350_REG3_12BIT_CLKDIV_MODE(0),
+	.r4_user_settings = ADF4350_REG4_OUTPUT_PWR(3) |
+			    ADF4350_REG4_MUTE_TILL_LOCK_EN,
+	.gpio_lock_detect = -1,
+};
+
+static int adf4350_sync_config(struct adf4350_state *st)
+{
+	int ret, i, doublebuf = 0;
+
+	for (i = ADF4350_REG5; i >= ADF4350_REG0; i--) {
+		if ((st->regs_hw[i] != st->regs[i]) ||
+			((i == ADF4350_REG0) && doublebuf)) {
+
+			switch (i) {
+			case ADF4350_REG1:
+			case ADF4350_REG4:
+				doublebuf = 1;
+				break;
+			}
+
+			st->val  = cpu_to_be32(st->regs[i] | i);
+			ret = spi_write(st->spi, &st->val, 4);
+			if (ret < 0)
+				return ret;
+			st->regs_hw[i] = st->regs[i];
+			dev_dbg(&st->spi->dev, "[%d] 0x%X\n",
+				i, (u32)st->regs[i] | i);
+		}
+	}
+	return 0;
+}
+
+static int adf4350_reg_access(struct iio_dev *indio_dev,
+			      unsigned reg, unsigned writeval,
+			      unsigned *readval)
+{
+	struct adf4350_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (reg > ADF4350_REG5)
+		return -EINVAL;
+
+	mutex_lock(&indio_dev->mlock);
+	if (readval == NULL) {
+		st->regs[reg] = writeval & ~(BIT(0) | BIT(1) | BIT(2));
+		ret = adf4350_sync_config(st);
+	} else {
+		*readval =  st->regs_hw[reg];
+		ret = 0;
+	}
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static int adf4350_tune_r_cnt(struct adf4350_state *st, unsigned short r_cnt)
+{
+	struct adf4350_platform_data *pdata = st->pdata;
+
+	do {
+		r_cnt++;
+		st->fpfd = (st->clkin * (pdata->ref_doubler_en ? 2 : 1)) /
+			   (r_cnt * (pdata->ref_div2_en ? 2 : 1));
+	} while (st->fpfd > ADF4350_MAX_FREQ_PFD);
+
+	return r_cnt;
+}
+
+static int adf4350_set_freq(struct adf4350_state *st, unsigned long long freq)
+{
+	struct adf4350_platform_data *pdata = st->pdata;
+	u64 tmp;
+	u32 div_gcd, prescaler;
+	u16 mdiv, r_cnt = 0;
+	u8 band_sel_div;
+
+	if (freq > ADF4350_MAX_OUT_FREQ || freq < st->min_out_freq)
+		return -EINVAL;
+
+	if (freq > ADF4350_MAX_FREQ_45_PRESC) {
+		prescaler = ADF4350_REG1_PRESCALER;
+		mdiv = 75;
+	} else {
+		prescaler = 0;
+		mdiv = 23;
+	}
+
+	st->r4_rf_div_sel = 0;
+
+	while (freq < ADF4350_MIN_VCO_FREQ) {
+		freq <<= 1;
+		st->r4_rf_div_sel++;
+	}
+
+	/*
+	 * Allow a predefined reference division factor
+	 * if not set, compute our own
+	 */
+	if (pdata->ref_div_factor)
+		r_cnt = pdata->ref_div_factor - 1;
+
+	do  {
+		r_cnt = adf4350_tune_r_cnt(st, r_cnt);
+
+		st->r1_mod = st->fpfd / st->chspc;
+		while (st->r1_mod > ADF4350_MAX_MODULUS) {
+			r_cnt = adf4350_tune_r_cnt(st, r_cnt);
+			st->r1_mod = st->fpfd / st->chspc;
+		}
+
+		tmp = freq * (u64)st->r1_mod + (st->fpfd > 1);
+		do_div(tmp, st->fpfd); /* Div round closest (n + d/2)/d */
+		st->r0_fract = do_div(tmp, st->r1_mod);
+		st->r0_int = tmp;
+	} while (mdiv > st->r0_int);
+
+	band_sel_div = DIV_ROUND_UP(st->fpfd, ADF4350_MAX_BANDSEL_CLK);
+
+	if (st->r0_fract && st->r1_mod) {
+		div_gcd = gcd(st->r1_mod, st->r0_fract);
+		st->r1_mod /= div_gcd;
+		st->r0_fract /= div_gcd;
+	} else {
+		st->r0_fract = 0;
+		st->r1_mod = 1;
+	}
+
+	dev_dbg(&st->spi->dev, "VCO: %llu Hz, PFD %lu Hz\n"
+		"REF_DIV %d, R0_INT %d, R0_FRACT %d\n"
+		"R1_MOD %d, RF_DIV %d\nPRESCALER %s, BAND_SEL_DIV %d\n",
+		freq, st->fpfd, r_cnt, st->r0_int, st->r0_fract, st->r1_mod,
+		1 << st->r4_rf_div_sel, prescaler ? "8/9" : "4/5",
+		band_sel_div);
+
+	st->regs[ADF4350_REG0] = ADF4350_REG0_INT(st->r0_int) |
+				 ADF4350_REG0_FRACT(st->r0_fract);
+
+	st->regs[ADF4350_REG1] = ADF4350_REG1_PHASE(0) |
+				 ADF4350_REG1_MOD(st->r1_mod) |
+				 prescaler;
+
+	st->regs[ADF4350_REG2] =
+		ADF4350_REG2_10BIT_R_CNT(r_cnt) |
+		ADF4350_REG2_DOUBLE_BUFF_EN |
+		(pdata->ref_doubler_en ? ADF4350_REG2_RMULT2_EN : 0) |
+		(pdata->ref_div2_en ? ADF4350_REG2_RDIV2_EN : 0) |
+		(pdata->r2_user_settings & (ADF4350_REG2_PD_POLARITY_POS |
+		ADF4350_REG2_LDP_6ns | ADF4350_REG2_LDF_INT_N |
+		ADF4350_REG2_CHARGE_PUMP_CURR_uA(5000) |
+		ADF4350_REG2_MUXOUT(0x7) | ADF4350_REG2_NOISE_MODE(0x9)));
+
+	st->regs[ADF4350_REG3] = pdata->r3_user_settings &
+				 (ADF4350_REG3_12BIT_CLKDIV(0xFFF) |
+				 ADF4350_REG3_12BIT_CLKDIV_MODE(0x3) |
+				 ADF4350_REG3_12BIT_CSR_EN |
+				 ADF4351_REG3_CHARGE_CANCELLATION_EN |
+				 ADF4351_REG3_ANTI_BACKLASH_3ns_EN |
+				 ADF4351_REG3_BAND_SEL_CLOCK_MODE_HIGH);
+
+	st->regs[ADF4350_REG4] =
+		ADF4350_REG4_FEEDBACK_FUND |
+		ADF4350_REG4_RF_DIV_SEL(st->r4_rf_div_sel) |
+		ADF4350_REG4_8BIT_BAND_SEL_CLKDIV(band_sel_div) |
+		ADF4350_REG4_RF_OUT_EN |
+		(pdata->r4_user_settings &
+		(ADF4350_REG4_OUTPUT_PWR(0x3) |
+		ADF4350_REG4_AUX_OUTPUT_PWR(0x3) |
+		ADF4350_REG4_AUX_OUTPUT_EN |
+		ADF4350_REG4_AUX_OUTPUT_FUND |
+		ADF4350_REG4_MUTE_TILL_LOCK_EN));
+
+	st->regs[ADF4350_REG5] = ADF4350_REG5_LD_PIN_MODE_DIGITAL;
+
+	return adf4350_sync_config(st);
+}
+
+static ssize_t adf4350_write(struct iio_dev *indio_dev,
+				    uintptr_t private,
+				    const struct iio_chan_spec *chan,
+				    const char *buf, size_t len)
+{
+	struct adf4350_state *st = iio_priv(indio_dev);
+	unsigned long long readin;
+	int ret;
+
+	ret = kstrtoull(buf, 10, &readin);
+	if (ret)
+		return ret;
+
+	mutex_lock(&indio_dev->mlock);
+	switch ((u32)private) {
+	case ADF4350_FREQ:
+		ret = adf4350_set_freq(st, readin);
+		break;
+	case ADF4350_FREQ_REFIN:
+		if (readin > ADF4350_MAX_FREQ_REFIN)
+			ret = -EINVAL;
+		else
+			st->clkin = readin;
+		break;
+	case ADF4350_FREQ_RESOLUTION:
+		if (readin == 0)
+			ret = -EINVAL;
+		else
+			st->chspc = readin;
+		break;
+	case ADF4350_PWRDOWN:
+		if (readin)
+			st->regs[ADF4350_REG2] |= ADF4350_REG2_POWER_DOWN_EN;
+		else
+			st->regs[ADF4350_REG2] &= ~ADF4350_REG2_POWER_DOWN_EN;
+
+		adf4350_sync_config(st);
+		break;
+	default:
+		ret = -ENODEV;
+	}
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret ? ret : len;
+}
+
+static ssize_t adf4350_read(struct iio_dev *indio_dev,
+				   uintptr_t private,
+				   const struct iio_chan_spec *chan,
+				   char *buf)
+{
+	struct adf4350_state *st = iio_priv(indio_dev);
+	unsigned long long val;
+	int ret = 0;
+
+	mutex_lock(&indio_dev->mlock);
+	switch ((u32)private) {
+	case ADF4350_FREQ:
+		val = (u64)((st->r0_int * st->r1_mod) + st->r0_fract) *
+			(u64)st->fpfd;
+		do_div(val, st->r1_mod * (1 << st->r4_rf_div_sel));
+		/* PLL unlocked? return error */
+		if (gpio_is_valid(st->pdata->gpio_lock_detect))
+			if (!gpio_get_value(st->pdata->gpio_lock_detect)) {
+				dev_dbg(&st->spi->dev, "PLL un-locked\n");
+				ret = -EBUSY;
+			}
+		break;
+	case ADF4350_FREQ_REFIN:
+		val = st->clkin;
+		break;
+	case ADF4350_FREQ_RESOLUTION:
+		val = st->chspc;
+		break;
+	case ADF4350_PWRDOWN:
+		val = !!(st->regs[ADF4350_REG2] & ADF4350_REG2_POWER_DOWN_EN);
+		break;
+	}
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret < 0 ? ret : sprintf(buf, "%llu\n", val);
+}
+
+#define _ADF4350_EXT_INFO(_name, _ident) { \
+	.name = _name, \
+	.read = adf4350_read, \
+	.write = adf4350_write, \
+	.private = _ident, \
+}
+
+static const struct iio_chan_spec_ext_info adf4350_ext_info[] = {
+	/* Ideally we use IIO_CHAN_INFO_FREQUENCY, but there are
+	 * values > 2^32 in order to support the entire frequency range
+	 * in Hz. Using scale is a bit ugly.
+	 */
+	_ADF4350_EXT_INFO("frequency", ADF4350_FREQ),
+	_ADF4350_EXT_INFO("frequency_resolution", ADF4350_FREQ_RESOLUTION),
+	_ADF4350_EXT_INFO("refin_frequency", ADF4350_FREQ_REFIN),
+	_ADF4350_EXT_INFO("powerdown", ADF4350_PWRDOWN),
+	{ },
+};
+
+static const struct iio_chan_spec adf4350_chan = {
+	.type = IIO_ALTVOLTAGE,
+	.indexed = 1,
+	.output = 1,
+	.ext_info = adf4350_ext_info,
+};
+
+static const struct iio_info adf4350_info = {
+	.debugfs_reg_access = &adf4350_reg_access,
+	.driver_module = THIS_MODULE,
+};
+
+static int __devinit adf4350_probe(struct spi_device *spi)
+{
+	struct adf4350_platform_data *pdata = spi->dev.platform_data;
+	struct iio_dev *indio_dev;
+	struct adf4350_state *st;
+	int ret;
+
+	if (!pdata) {
+		dev_warn(&spi->dev, "no platform data? using default\n");
+
+		pdata = &default_pdata;
+	}
+
+	indio_dev = iio_device_alloc(sizeof(*st));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+
+	st->reg = regulator_get(&spi->dev, "vcc");
+	if (!IS_ERR(st->reg)) {
+		ret = regulator_enable(st->reg);
+		if (ret)
+			goto error_put_reg;
+	}
+
+	spi_set_drvdata(spi, indio_dev);
+	st->spi = spi;
+	st->pdata = pdata;
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = (pdata->name[0] != 0) ? pdata->name :
+		spi_get_device_id(spi)->name;
+
+	indio_dev->info = &adf4350_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = &adf4350_chan;
+	indio_dev->num_channels = 1;
+
+	st->chspc = pdata->channel_spacing;
+	st->clkin = pdata->clkin;
+
+	st->min_out_freq = spi_get_device_id(spi)->driver_data == 4351 ?
+		ADF4351_MIN_OUT_FREQ : ADF4350_MIN_OUT_FREQ;
+
+	memset(st->regs_hw, 0xFF, sizeof(st->regs_hw));
+
+	if (gpio_is_valid(pdata->gpio_lock_detect)) {
+		ret = gpio_request(pdata->gpio_lock_detect, indio_dev->name);
+		if (ret) {
+			dev_err(&spi->dev, "fail to request lock detect GPIO-%d",
+				pdata->gpio_lock_detect);
+			goto error_disable_reg;
+		}
+		gpio_direction_input(pdata->gpio_lock_detect);
+	}
+
+	if (pdata->power_up_frequency) {
+		ret = adf4350_set_freq(st, pdata->power_up_frequency);
+		if (ret)
+			goto error_free_gpio;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_free_gpio;
+
+	return 0;
+
+error_free_gpio:
+	if (gpio_is_valid(pdata->gpio_lock_detect))
+		gpio_free(pdata->gpio_lock_detect);
+
+error_disable_reg:
+	if (!IS_ERR(st->reg))
+		regulator_disable(st->reg);
+error_put_reg:
+	if (!IS_ERR(st->reg))
+		regulator_put(st->reg);
+
+	iio_device_free(indio_dev);
+
+	return ret;
+}
+
+static int __devexit adf4350_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct adf4350_state *st = iio_priv(indio_dev);
+	struct regulator *reg = st->reg;
+
+	st->regs[ADF4350_REG2] |= ADF4350_REG2_POWER_DOWN_EN;
+	adf4350_sync_config(st);
+
+	iio_device_unregister(indio_dev);
+
+	if (!IS_ERR(reg)) {
+		regulator_disable(reg);
+		regulator_put(reg);
+	}
+
+	if (gpio_is_valid(st->pdata->gpio_lock_detect))
+		gpio_free(st->pdata->gpio_lock_detect);
+
+	iio_device_free(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id adf4350_id[] = {
+	{"adf4350", 4350},
+	{"adf4351", 4351},
+	{}
+};
+
+static struct spi_driver adf4350_driver = {
+	.driver = {
+		.name	= "adf4350",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= adf4350_probe,
+	.remove		= __devexit_p(adf4350_remove),
+	.id_table	= adf4350_id,
+};
+module_spi_driver(adf4350_driver);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices ADF4350/ADF4351 PLL");
+MODULE_LICENSE("GPL v2");