Message-Id: <20230319202256.352939-1-william.gray@linaro.org>
Date:   Sun, 19 Mar 2023 16:22:56 -0400
From:   William Breathitt Gray <william.gray@...aro.org>
To:     Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        William Breathitt Gray <william.gray@...aro.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH] iio: addac: stx104: Migrate to the regmap API

The regmap API supports IO port accessors so we can take advantage of
regmap abstractions rather than handling access to the device registers
directly in the driver.

Suggested-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Signed-off-by: William Breathitt Gray <william.gray@...aro.org>
---
 drivers/iio/addac/Kconfig  |   2 +
 drivers/iio/addac/stx104.c | 422 ++++++++++++++++++++-----------------
 2 files changed, 231 insertions(+), 193 deletions(-)

diff --git a/drivers/iio/addac/Kconfig b/drivers/iio/addac/Kconfig
index 2843fcb70e24..877f9124803c 100644
--- a/drivers/iio/addac/Kconfig
+++ b/drivers/iio/addac/Kconfig
@@ -35,7 +35,9 @@ config STX104
 	tristate "Apex Embedded Systems STX104 driver"
 	depends on PC104 && X86
 	select ISA_BUS_API
+	select REGMAP_MMIO
 	select GPIOLIB
+	select GPIO_REGMAP
 	help
 	  Say yes here to build support for the Apex Embedded Systems STX104
 	  integrated analog PC/104 card.
diff --git a/drivers/iio/addac/stx104.c b/drivers/iio/addac/stx104.c
index e45b70aa5bb7..7e15410d3100 100644
--- a/drivers/iio/addac/stx104.c
+++ b/drivers/iio/addac/stx104.c
@@ -3,19 +3,18 @@
  * IIO driver for the Apex Embedded Systems STX104
  * Copyright (C) 2016 William Breathitt Gray
  */
+#include <linux/bitfield.h>
 #include <linux/bits.h>
 #include <linux/device.h>
-#include <linux/errno.h>
-#include <linux/gpio/driver.h>
+#include <linux/err.h>
+#include <linux/gpio/regmap.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/types.h>
-#include <linux/io.h>
-#include <linux/ioport.h>
 #include <linux/isa.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
-#include <linux/spinlock.h>
+#include <linux/regmap.h>
 #include <linux/types.h>
 
 #define STX104_OUT_CHAN(chan) {				\
@@ -45,101 +44,190 @@ static unsigned int num_stx104;
 module_param_hw_array(base, uint, ioport, &num_stx104, 0);
 MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
 
-/**
- * struct stx104_reg - device register structure
- * @ssr_ad:	Software Strobe Register and ADC Data
- * @achan:	ADC Channel
- * @dio:	Digital I/O
- * @dac:	DAC Channels
- * @cir_asr:	Clear Interrupts and ADC Status
- * @acr:	ADC Control
- * @pccr_fsh:	Pacer Clock Control and FIFO Status MSB
- * @acfg:	ADC Configuration
- */
-struct stx104_reg {
-	u16 ssr_ad;
-	u8 achan;
-	u8 dio;
-	u16 dac[2];
-	u8 cir_asr;
-	u8 acr;
-	u8 pccr_fsh;
-	u8 acfg;
+#define AIO_BASE 0x0
+#define SOFTWARE_STROBE AIO_BASE
+#define ADC_DATA AIO_BASE
+#define ADC_CHANNEL (AIO_BASE + 0x2)
+#define DIO_REG (AIO_BASE + 0x3)
+#define DAC_BASE (AIO_BASE + 0x4)
+#define ADC_STATUS (AIO_BASE + 0x8)
+#define ADC_CONTROL (AIO_BASE + 0x9)
+#define ADC_CONFIGURATION (AIO_BASE + 0x11)
+
+#define AIO_DATA_STRIDE 2
+#define DAC_OFFSET(_channel) (DAC_BASE + AIO_DATA_STRIDE * (_channel))
+
+/* ADC Channel */
+#define FC GENMASK(3, 0)
+#define LC GENMASK(7, 4)
+#define SAME_CHANNEL(_channel) (FIELD_PREP(FC, _channel) | FIELD_PREP(LC, _channel))
+
+/* ADC Status */
+#define SD BIT(5)
+#define CNV BIT(7)
+#define DIFFERENTIAL 1
+
+/* ADC Control */
+#define ALSS GENMASK(1, 0)
+#define SOFTWARE_TRIGGER 0
+
+/* ADC Configuration */
+#define GAIN GENMASK(1, 0)
+#define ADBU BIT(2)
+#define BIPOLAR 0
+#define GAIN_X1 0
+#define GAIN_X2 1
+#define GAIN_X4 2
+#define GAIN_X8 3
+
+static const struct regmap_range aio_ctl_wr_ranges[] = {
+	regmap_reg_range(0x0, 0x0), regmap_reg_range(0x2, 0x2), regmap_reg_range(0x9, 0x9),
+	regmap_reg_range(0x11, 0x11),
+};
+static const struct regmap_range aio_ctl_rd_ranges[] = {
+	regmap_reg_range(0x2, 0x2), regmap_reg_range(0x8, 0x9), regmap_reg_range(0x11, 0x11),
+};
+static const struct regmap_range aio_ctl_volatile_ranges[] = {
+	regmap_reg_range(0x8, 0x8),
+};
+static const struct regmap_access_table aio_ctl_wr_table = {
+	.yes_ranges = aio_ctl_wr_ranges,
+	.n_yes_ranges = ARRAY_SIZE(aio_ctl_wr_ranges),
+};
+static const struct regmap_access_table aio_ctl_rd_table = {
+	.yes_ranges = aio_ctl_rd_ranges,
+	.n_yes_ranges = ARRAY_SIZE(aio_ctl_rd_ranges),
+};
+static const struct regmap_access_table aio_ctl_volatile_table = {
+	.yes_ranges = aio_ctl_volatile_ranges,
+	.n_yes_ranges = ARRAY_SIZE(aio_ctl_volatile_ranges),
 };
 
-/**
- * struct stx104_iio - IIO device private data structure
- * @chan_out_states:	channels' output states
- * @reg:		I/O address offset for the device registers
- */
-struct stx104_iio {
-	unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
-	struct stx104_reg __iomem *reg;
+static const struct regmap_config aio_ctl_regmap_config = {
+	.name = "aio_ctl",
+	.reg_bits = 8,
+	.reg_stride = 1,
+	.val_bits = 8,
+	.io_port = true,
+	.max_register = 0x11,
+	.wr_table = &aio_ctl_wr_table,
+	.rd_table = &aio_ctl_rd_table,
+	.volatile_table = &aio_ctl_volatile_table,
+	.cache_type = REGCACHE_FLAT,
+};
+
+static const struct regmap_range aio_data_wr_ranges[] = {
+	regmap_reg_range(0x4, 0x7),
+};
+static const struct regmap_range aio_data_rd_ranges[] = {
+	regmap_reg_range(0x0, 0x1),
+};
+static const struct regmap_access_table aio_data_wr_table = {
+	.yes_ranges = aio_data_wr_ranges,
+	.n_yes_ranges = ARRAY_SIZE(aio_data_wr_ranges),
+};
+static const struct regmap_access_table aio_data_rd_table = {
+	.yes_ranges = aio_data_rd_ranges,
+	.n_yes_ranges = ARRAY_SIZE(aio_data_rd_ranges),
+};
+
+static const struct regmap_config aio_data_regmap_config = {
+	.name = "aio_data",
+	.reg_bits = 16,
+	.reg_stride = AIO_DATA_STRIDE,
+	.val_bits = 16,
+	.io_port = true,
+	.max_register = 0x7,
+	.wr_table = &aio_data_wr_table,
+	.rd_table = &aio_data_rd_table,
+	.volatile_table = &aio_data_rd_table,
+	.cache_type = REGCACHE_FLAT,
+};
+
+static const struct regmap_config dio_regmap_config = {
+	.name = "dio",
+	.reg_bits = 8,
+	.reg_stride = 1,
+	.val_bits = 8,
+	.io_port = true,
+	.max_register = 0x0,
 };
 
 /**
- * struct stx104_gpio - GPIO device private data structure
- * @chip:	instance of the gpio_chip
- * @lock:	synchronization lock to prevent I/O race conditions
- * @base:	base port address of the GPIO device
- * @out_state:	output bits state
+ * struct stx104_iio - IIO device private data structure
+ * @aio_data_map: Regmap for analog I/O data
+ * @aio_ctl_map: Regmap for analog I/O control
  */
-struct stx104_gpio {
-	struct gpio_chip chip;
-	spinlock_t lock;
-	u8 __iomem *base;
-	unsigned int out_state;
+struct stx104_iio {
+	struct regmap *aio_data_map;
+	struct regmap *aio_ctl_map;
 };
 
 static int stx104_read_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
 {
 	struct stx104_iio *const priv = iio_priv(indio_dev);
-	struct stx104_reg __iomem *const reg = priv->reg;
+	int err;
 	unsigned int adc_config;
-	int adbu;
-	int gain;
+	unsigned int value;
+	unsigned int adc_status;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_HARDWAREGAIN:
-		/* get gain configuration */
-		adc_config = ioread8(&reg->acfg);
-		gain = adc_config & 0x3;
+		err = regmap_read(priv->aio_ctl_map, ADC_CONFIGURATION, &adc_config);
+		if (err)
+			return err;
 
-		*val = 1 << gain;
+		*val = 1 << FIELD_GET(GAIN, adc_config);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_RAW:
 		if (chan->output) {
-			*val = priv->chan_out_states[chan->channel];
+			err = regmap_read(priv->aio_data_map, DAC_OFFSET(chan->channel), &value);
+			if (err)
+				return err;
+			*val = value;
 			return IIO_VAL_INT;
 		}
 
 		/* select ADC channel */
-		iowrite8(chan->channel | (chan->channel << 4), &reg->achan);
+		err = regmap_write(priv->aio_ctl_map, ADC_CHANNEL, SAME_CHANNEL(chan->channel));
+		if (err)
+			return err;
 
 		/* trigger ADC sample capture by writing to the 8-bit
 		 * Software Strobe Register and wait for completion
 		 */
-		iowrite8(0, &reg->ssr_ad);
-		while (ioread8(&reg->cir_asr) & BIT(7));
-
-		*val = ioread16(&reg->ssr_ad);
+		err = regmap_write(priv->aio_ctl_map, SOFTWARE_STROBE, 0);
+		if (err)
+			return err;
+		do {
+			err = regmap_read(priv->aio_ctl_map, ADC_STATUS, &adc_status);
+			if (err)
+				return err;
+		} while (FIELD_GET(CNV, adc_status));
+
+		err = regmap_read(priv->aio_data_map, ADC_DATA, &value);
+		if (err)
+			return err;
+		*val = value;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_OFFSET:
 		/* get ADC bipolar/unipolar configuration */
-		adc_config = ioread8(&reg->acfg);
-		adbu = !(adc_config & BIT(2));
+		err = regmap_read(priv->aio_ctl_map, ADC_CONFIGURATION, &adc_config);
+		if (err)
+			return err;
 
-		*val = -32768 * adbu;
+		*val = (FIELD_GET(ADBU, adc_config) == BIPOLAR) ? -32768 : 0;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		/* get ADC bipolar/unipolar and gain configuration */
-		adc_config = ioread8(&reg->acfg);
-		adbu = !(adc_config & BIT(2));
-		gain = adc_config & 0x3;
+		err = regmap_read(priv->aio_ctl_map, ADC_CONFIGURATION, &adc_config);
+		if (err)
+			return err;
 
 		*val = 5;
-		*val2 = 15 - adbu + gain;
+		*val2 = (FIELD_GET(ADBU, adc_config) == BIPOLAR) ? 14 : 15;
+		*val2 += FIELD_GET(GAIN, adc_config);
 		return IIO_VAL_FRACTIONAL_LOG2;
 	}
 
@@ -150,38 +238,36 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int val, int val2, long mask)
 {
 	struct stx104_iio *const priv = iio_priv(indio_dev);
+	u8 gain;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_HARDWAREGAIN:
 		/* Only four gain states (x1, x2, x4, x8) */
 		switch (val) {
 		case 1:
-			iowrite8(0, &priv->reg->acfg);
+			gain = GAIN_X1;
 			break;
 		case 2:
-			iowrite8(1, &priv->reg->acfg);
+			gain = GAIN_X2;
 			break;
 		case 4:
-			iowrite8(2, &priv->reg->acfg);
+			gain = GAIN_X4;
 			break;
 		case 8:
-			iowrite8(3, &priv->reg->acfg);
+			gain = GAIN_X8;
 			break;
 		default:
 			return -EINVAL;
 		}
 
-		return 0;
+		return regmap_write(priv->aio_ctl_map, ADC_CONFIGURATION, gain);
 	case IIO_CHAN_INFO_RAW:
 		if (chan->output) {
 			/* DAC can only accept up to a 16-bit value */
 			if ((unsigned int)val > 65535)
 				return -EINVAL;
 
-			priv->chan_out_states[chan->channel] = val;
-			iowrite16(val, &priv->reg->dac[chan->channel]);
-
-			return 0;
+			return regmap_write(priv->aio_data_map, DAC_OFFSET(chan->channel), val);
 		}
 		return -EINVAL;
 	}
@@ -212,119 +298,66 @@ static const struct iio_chan_spec stx104_channels_diff[] = {
 	STX104_IN_CHAN(6, 1), STX104_IN_CHAN(7, 1)
 };
 
-static int stx104_gpio_get_direction(struct gpio_chip *chip,
-	unsigned int offset)
-{
-	/* GPIO 0-3 are input only, while the rest are output only */
-	if (offset < 4)
-		return 1;
-
-	return 0;
-}
-
-static int stx104_gpio_direction_input(struct gpio_chip *chip,
-	unsigned int offset)
-{
-	if (offset >= 4)
-		return -EINVAL;
-
-	return 0;
-}
-
-static int stx104_gpio_direction_output(struct gpio_chip *chip,
-	unsigned int offset, int value)
-{
-	if (offset < 4)
-		return -EINVAL;
-
-	chip->set(chip, offset, value);
-	return 0;
-}
-
-static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
+static int stx104_reg_mask_xlate(struct gpio_regmap *const gpio, const unsigned int base,
+				 unsigned int offset, unsigned int *const reg,
+				 unsigned int *const mask)
 {
-	struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
-
+	/* Output lines are located at same register bit offsets as input lines */
 	if (offset >= 4)
-		return -EINVAL;
-
-	return !!(ioread8(stx104gpio->base) & BIT(offset));
-}
-
-static int stx104_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
-	unsigned long *bits)
-{
-	struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
+		offset -= 4;
 
-	*bits = ioread8(stx104gpio->base);
+	*reg = base;
+	*mask = BIT(offset);
 
 	return 0;
 }
 
-static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
-	int value)
-{
-	struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
-	const unsigned int mask = BIT(offset) >> 4;
-	unsigned long flags;
-
-	if (offset < 4)
-		return;
-
-	spin_lock_irqsave(&stx104gpio->lock, flags);
-
-	if (value)
-		stx104gpio->out_state |= mask;
-	else
-		stx104gpio->out_state &= ~mask;
-
-	iowrite8(stx104gpio->out_state, stx104gpio->base);
-
-	spin_unlock_irqrestore(&stx104gpio->lock, flags);
-}
-
 #define STX104_NGPIO 8
 static const char *stx104_names[STX104_NGPIO] = {
 	"DIN0", "DIN1", "DIN2", "DIN3", "DOUT0", "DOUT1", "DOUT2", "DOUT3"
 };
 
-static void stx104_gpio_set_multiple(struct gpio_chip *chip,
-	unsigned long *mask, unsigned long *bits)
+static int stx104_init_hw(struct stx104_iio *const priv)
 {
-	struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
-	unsigned long flags;
-
-	/* verify masked GPIO are output */
-	if (!(*mask & 0xF0))
-		return;
+	int err;
 
-	*mask >>= 4;
-	*bits >>= 4;
+	/* configure device for software trigger operation */
+	err = regmap_write(priv->aio_ctl_map, ADC_CONTROL, SOFTWARE_TRIGGER);
+	if (err)
+		return err;
 
-	spin_lock_irqsave(&stx104gpio->lock, flags);
+	/* initialize gain setting to x1 */
+	err = regmap_write(priv->aio_ctl_map, ADC_CONFIGURATION, GAIN_X1);
+	if (err)
+		return err;
 
-	stx104gpio->out_state &= ~*mask;
-	stx104gpio->out_state |= *mask & *bits;
-	iowrite8(stx104gpio->out_state, stx104gpio->base);
+	/* initialize DAC outputs to 0V */
+	err = regmap_write(priv->aio_data_map, DAC_BASE, 0);
+	if (err)
+		return err;
+	err = regmap_write(priv->aio_data_map, DAC_BASE + AIO_DATA_STRIDE, 0);
+	if (err)
+		return err;
 
-	spin_unlock_irqrestore(&stx104gpio->lock, flags);
+	return 0;
 }
 
 static int stx104_probe(struct device *dev, unsigned int id)
 {
 	struct iio_dev *indio_dev;
 	struct stx104_iio *priv;
-	struct stx104_gpio *stx104gpio;
+	struct gpio_regmap_config gpio_config = {};
+	void __iomem *stx104_base;
+	struct regmap *aio_ctl_map;
+	struct regmap *aio_data_map;
+	struct regmap *dio_map;
 	int err;
+	unsigned int adc_status;
 
 	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
 	if (!indio_dev)
 		return -ENOMEM;
 
-	stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL);
-	if (!stx104gpio)
-		return -ENOMEM;
-
 	if (!devm_request_region(dev, base[id], STX104_EXTENT,
 		dev_name(dev))) {
 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
@@ -332,16 +365,35 @@ static int stx104_probe(struct device *dev, unsigned int id)
 		return -EBUSY;
 	}
 
-	priv = iio_priv(indio_dev);
-	priv->reg = devm_ioport_map(dev, base[id], STX104_EXTENT);
-	if (!priv->reg)
+	stx104_base = devm_ioport_map(dev, base[id], STX104_EXTENT);
+	if (!stx104_base)
 		return -ENOMEM;
 
+	aio_ctl_map = devm_regmap_init_mmio(dev, stx104_base + AIO_BASE, &aio_ctl_regmap_config);
+	if (IS_ERR(aio_ctl_map))
+		return dev_err_probe(dev, PTR_ERR(aio_ctl_map),
+				     "Unable to initialize aio_ctl register map\n");
+	aio_data_map = devm_regmap_init_mmio(dev, stx104_base + AIO_BASE, &aio_data_regmap_config);
+	if (IS_ERR(aio_data_map))
+		return dev_err_probe(dev, PTR_ERR(aio_data_map),
+				     "Unable to initialize aio_data register map\n");
+	dio_map = devm_regmap_init_mmio(dev, stx104_base + DIO_REG, &dio_regmap_config);
+	if (IS_ERR(dio_map))
+		return dev_err_probe(dev, PTR_ERR(dio_map),
+				     "Unable to initialize dio register map\n");
+
+	priv = iio_priv(indio_dev);
+	priv->aio_ctl_map = aio_ctl_map;
+	priv->aio_data_map = aio_data_map;
+
 	indio_dev->info = &stx104_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
-	/* determine if differential inputs */
-	if (ioread8(&priv->reg->cir_asr) & BIT(5)) {
+	err = regmap_read(aio_ctl_map, ADC_STATUS, &adc_status);
+	if (err)
+		return err;
+
+	if (FIELD_GET(SD, adc_status) == DIFFERENTIAL) {
 		indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
 		indio_dev->channels = stx104_channels_diff;
 	} else {
@@ -351,41 +403,25 @@ static int stx104_probe(struct device *dev, unsigned int id)
 
 	indio_dev->name = dev_name(dev);
 
-	/* configure device for software trigger operation */
-	iowrite8(0, &priv->reg->acr);
+	err = stx104_init_hw(priv);
+	if (err)
+		return err;
 
-	/* initialize gain setting to x1 */
-	iowrite8(0, &priv->reg->acfg);
-
-	/* initialize DAC output to 0V */
-	iowrite16(0, &priv->reg->dac[0]);
-	iowrite16(0, &priv->reg->dac[1]);
-
-	stx104gpio->chip.label = dev_name(dev);
-	stx104gpio->chip.parent = dev;
-	stx104gpio->chip.owner = THIS_MODULE;
-	stx104gpio->chip.base = -1;
-	stx104gpio->chip.ngpio = STX104_NGPIO;
-	stx104gpio->chip.names = stx104_names;
-	stx104gpio->chip.get_direction = stx104_gpio_get_direction;
-	stx104gpio->chip.direction_input = stx104_gpio_direction_input;
-	stx104gpio->chip.direction_output = stx104_gpio_direction_output;
-	stx104gpio->chip.get = stx104_gpio_get;
-	stx104gpio->chip.get_multiple = stx104_gpio_get_multiple;
-	stx104gpio->chip.set = stx104_gpio_set;
-	stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
-	stx104gpio->base = &priv->reg->dio;
-	stx104gpio->out_state = 0x0;
-
-	spin_lock_init(&stx104gpio->lock);
-
-	err = devm_gpiochip_add_data(dev, &stx104gpio->chip, stx104gpio);
-	if (err) {
-		dev_err(dev, "GPIO registering failed (%d)\n", err);
+	err = devm_iio_device_register(dev, indio_dev);
+	if (err)
 		return err;
-	}
 
-	return devm_iio_device_register(dev, indio_dev);
+	gpio_config.parent = dev;
+	gpio_config.regmap = dio_map;
+	gpio_config.ngpio = STX104_NGPIO;
+	gpio_config.names = stx104_names;
+	gpio_config.reg_dat_base = GPIO_REGMAP_ADDR(DIO_REG);
+	gpio_config.reg_set_base = GPIO_REGMAP_ADDR(DIO_REG);
+	gpio_config.ngpio_per_reg = STX104_NGPIO;
+	gpio_config.reg_mask_xlate = stx104_reg_mask_xlate;
+	gpio_config.drvdata = dio_map;
+
+	return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
 }
 
 static struct isa_driver stx104_driver = {

base-commit: 46e33707fe95a21aa9896bded0be97285b779509
-- 
2.39.2

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