spi: cs42l43: Add SPI controller support

The CS42L43 is an audio CODEC with integrated MIPI SoundWire interface
(Version 1.2.1 compliant), I2C, SPI, and I2S/TDM interfaces designed
for portable applications. It provides a high dynamic range, stereo
DAC for headphone output, two integrated Class D amplifiers for
loudspeakers, and two ADCs for wired headset microphone input or
stereo line input. PDM inputs are provided for digital microphones.

The SPI component incorporates a SPI controller interface for
communication with other peripheral components.

Signed-off-by: Lucas Tanure <tanureal@opensource.cirrus.com>
Signed-off-by: Maciej Strozek <mstrozek@opensource.cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230804104602.395892-6-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

MAINTAINERS

@@ -4888,6 +4888,7 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/sound/cirrus,cs*
 F:	drivers/mfd/cs42l43*
 F:	drivers/pinctrl/cirrus/pinctrl-cs42l43*
+F:	drivers/spi/spi-cs42l43*
 F:	include/dt-bindings/sound/cs*
 F:	include/linux/mfd/cs42l43*
 F:	include/sound/cs*

drivers/spi/Kconfig

@@ -281,6 +281,13 @@ config SPI_COLDFIRE_QSPI
 	  This enables support for the Coldfire QSPI controller in master
 	  mode.
 
+config SPI_CS42L43
+	tristate "Cirrus Logic CS42L43 SPI controller"
+	depends on MFD_CS42L43 && PINCTRL_CS42L43
+	help
+	  This enables support for the SPI controller inside the Cirrus Logic
+	  CS42L43 audio codec.
+
 config SPI_DAVINCI
 	tristate "Texas Instruments DaVinci/DA8x/OMAP-L/AM1x SoC SPI controller"
 	depends on ARCH_DAVINCI || ARCH_KEYSTONE || COMPILE_TEST

drivers/spi/Makefile

@@ -40,6 +40,7 @@ obj-$(CONFIG_SPI_CADENCE_QUADSPI)	+= spi-cadence-quadspi.o
 obj-$(CONFIG_SPI_CADENCE_XSPI)		+= spi-cadence-xspi.o
 obj-$(CONFIG_SPI_CLPS711X)		+= spi-clps711x.o
 obj-$(CONFIG_SPI_COLDFIRE_QSPI)		+= spi-coldfire-qspi.o
+obj-$(CONFIG_SPI_CS42L43)		+= spi-cs42l43.o
 obj-$(CONFIG_SPI_DAVINCI)		+= spi-davinci.o
 obj-$(CONFIG_SPI_DLN2)			+= spi-dln2.o
 obj-$(CONFIG_SPI_DESIGNWARE)		+= spi-dw.o

drivers/spi/spi-cs42l43.c

@@ -0,0 +1,284 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// CS42L43 SPI Controller Driver
+//
+// Copyright (C) 2022-2023 Cirrus Logic, Inc. and
+//                         Cirrus Logic International Semiconductor Ltd.
+
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/mfd/cs42l43.h>
+#include <linux/mfd/cs42l43-regs.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/units.h>
+
+#define CS42L43_FIFO_SIZE		16
+#define CS42L43_SPI_ROOT_HZ		(40 * HZ_PER_MHZ)
+#define CS42L43_SPI_MAX_LENGTH		65532
+
+enum cs42l43_spi_cmd {
+	CS42L43_WRITE,
+	CS42L43_READ
+};
+
+struct cs42l43_spi {
+	struct device *dev;
+	struct regmap *regmap;
+	struct spi_controller *ctlr;
+};
+
+static const unsigned int cs42l43_clock_divs[] = {
+	2, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30
+};
+
+static int cs42l43_spi_tx(struct regmap *regmap, const u8 *buf, unsigned int len)
+{
+	const u8 *end = buf + len;
+	u32 val = 0;
+	int ret;
+
+	while (buf < end) {
+		const u8 *block = min(buf + CS42L43_FIFO_SIZE, end);
+
+		while (buf < block) {
+			const u8 *word = min(buf + sizeof(u32), block);
+			int pad = (buf + sizeof(u32)) - word;
+
+			while (buf < word) {
+				val >>= BITS_PER_BYTE;
+				val |= FIELD_PREP(GENMASK(31, 24), *buf);
+
+				buf++;
+			}
+
+			val >>= pad * BITS_PER_BYTE;
+
+			regmap_write(regmap, CS42L43_TX_DATA, val);
+		}
+
+		regmap_write(regmap, CS42L43_TRAN_CONFIG8, CS42L43_SPI_TX_DONE_MASK);
+
+		ret = regmap_read_poll_timeout(regmap, CS42L43_TRAN_STATUS1,
+					       val, (val & CS42L43_SPI_TX_REQUEST_MASK),
+					       1000, 5000);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int cs42l43_spi_rx(struct regmap *regmap, u8 *buf, unsigned int len)
+{
+	u8 *end = buf + len;
+	u32 val;
+	int ret;
+
+	while (buf < end) {
+		u8 *block = min(buf + CS42L43_FIFO_SIZE, end);
+
+		ret = regmap_read_poll_timeout(regmap, CS42L43_TRAN_STATUS1,
+					       val, (val & CS42L43_SPI_RX_REQUEST_MASK),
+					       1000, 5000);
+		if (ret)
+			return ret;
+
+		while (buf < block) {
+			u8 *word = min(buf + sizeof(u32), block);
+
+			ret = regmap_read(regmap, CS42L43_RX_DATA, &val);
+			if (ret)
+				return ret;
+
+			while (buf < word) {
+				*buf = FIELD_GET(GENMASK(7, 0), val);
+
+				val >>= BITS_PER_BYTE;
+				buf++;
+			}
+		}
+
+		regmap_write(regmap, CS42L43_TRAN_CONFIG8, CS42L43_SPI_RX_DONE_MASK);
+	}
+
+	return 0;
+}
+
+static int cs42l43_transfer_one(struct spi_controller *ctlr, struct spi_device *spi,
+				struct spi_transfer *tfr)
+{
+	struct cs42l43_spi *priv = spi_controller_get_devdata(spi->controller);
+	int i, ret = -EINVAL;
+
+	for (i = 0; i < ARRAY_SIZE(cs42l43_clock_divs); i++) {
+		if (CS42L43_SPI_ROOT_HZ / cs42l43_clock_divs[i] <= tfr->speed_hz)
+			break;
+	}
+
+	if (i == ARRAY_SIZE(cs42l43_clock_divs))
+		return -EINVAL;
+
+	regmap_write(priv->regmap, CS42L43_SPI_CLK_CONFIG1, i);
+
+	if (tfr->tx_buf) {
+		regmap_write(priv->regmap, CS42L43_TRAN_CONFIG3, CS42L43_WRITE);
+		regmap_write(priv->regmap, CS42L43_TRAN_CONFIG4, tfr->len - 1);
+	} else if (tfr->rx_buf) {
+		regmap_write(priv->regmap, CS42L43_TRAN_CONFIG3, CS42L43_READ);
+		regmap_write(priv->regmap, CS42L43_TRAN_CONFIG5, tfr->len - 1);
+	}
+
+	regmap_write(priv->regmap, CS42L43_TRAN_CONFIG1, CS42L43_SPI_START_MASK);
+
+	if (tfr->tx_buf)
+		ret = cs42l43_spi_tx(priv->regmap, (const u8 *)tfr->tx_buf, tfr->len);
+	else if (tfr->rx_buf)
+		ret = cs42l43_spi_rx(priv->regmap, (u8 *)tfr->rx_buf, tfr->len);
+
+	return ret;
+}
+
+static void cs42l43_set_cs(struct spi_device *spi, bool is_high)
+{
+	struct cs42l43_spi *priv = spi_controller_get_devdata(spi->controller);
+
+	if (spi_get_chipselect(spi, 0) == 0)
+		regmap_write(priv->regmap, CS42L43_SPI_CONFIG2, !is_high);
+}
+
+static int cs42l43_prepare_message(struct spi_controller *ctlr, struct spi_message *msg)
+{
+	struct cs42l43_spi *priv = spi_controller_get_devdata(ctlr);
+	struct spi_device *spi = msg->spi;
+	unsigned int spi_config1 = 0;
+
+	/* select another internal CS, which doesn't exist, so CS 0 is not used */
+	if (spi_get_csgpiod(spi, 0))
+		spi_config1 |= 1 << CS42L43_SPI_SS_SEL_SHIFT;
+	if (spi->mode & SPI_CPOL)
+		spi_config1 |= CS42L43_SPI_CPOL_MASK;
+	if (spi->mode & SPI_CPHA)
+		spi_config1 |= CS42L43_SPI_CPHA_MASK;
+	if (spi->mode & SPI_3WIRE)
+		spi_config1 |= CS42L43_SPI_THREE_WIRE_MASK;
+
+	regmap_write(priv->regmap, CS42L43_SPI_CONFIG1, spi_config1);
+
+	return 0;
+}
+
+static int cs42l43_prepare_transfer_hardware(struct spi_controller *ctlr)
+{
+	struct cs42l43_spi *priv = spi_controller_get_devdata(ctlr);
+	int ret;
+
+	ret = regmap_write(priv->regmap, CS42L43_BLOCK_EN2, CS42L43_SPI_MSTR_EN_MASK);
+	if (ret)
+		dev_err(priv->dev, "Failed to enable SPI controller: %d\n", ret);
+
+	return ret;
+}
+
+static int cs42l43_unprepare_transfer_hardware(struct spi_controller *ctlr)
+{
+	struct cs42l43_spi *priv = spi_controller_get_devdata(ctlr);
+	int ret;
+
+	ret = regmap_write(priv->regmap, CS42L43_BLOCK_EN2, 0);
+	if (ret)
+		dev_err(priv->dev, "Failed to disable SPI controller: %d\n", ret);
+
+	return ret;
+}
+
+static size_t cs42l43_spi_max_length(struct spi_device *spi)
+{
+	return CS42L43_SPI_MAX_LENGTH;
+}
+
+static int cs42l43_spi_probe(struct platform_device *pdev)
+{
+	struct cs42l43 *cs42l43 = dev_get_drvdata(pdev->dev.parent);
+	struct cs42l43_spi *priv;
+	struct fwnode_handle *fwnode = dev_fwnode(cs42l43->dev);
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->ctlr = devm_spi_alloc_master(&pdev->dev, sizeof(*priv->ctlr));
+	if (!priv->ctlr)
+		return -ENOMEM;
+
+	spi_controller_set_devdata(priv->ctlr, priv);
+
+	priv->dev = &pdev->dev;
+	priv->regmap = cs42l43->regmap;
+
+	priv->ctlr->prepare_message = cs42l43_prepare_message;
+	priv->ctlr->prepare_transfer_hardware = cs42l43_prepare_transfer_hardware;
+	priv->ctlr->unprepare_transfer_hardware = cs42l43_unprepare_transfer_hardware;
+	priv->ctlr->transfer_one = cs42l43_transfer_one;
+	priv->ctlr->set_cs = cs42l43_set_cs;
+	priv->ctlr->max_transfer_size = cs42l43_spi_max_length;
+
+	if (is_of_node(fwnode))
+		fwnode = fwnode_get_named_child_node(fwnode, "spi");
+
+	device_set_node(&priv->ctlr->dev, fwnode);
+
+	priv->ctlr->mode_bits = SPI_3WIRE | SPI_MODE_X_MASK;
+	priv->ctlr->flags = SPI_CONTROLLER_HALF_DUPLEX;
+	priv->ctlr->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16) |
+					 SPI_BPW_MASK(32);
+	priv->ctlr->min_speed_hz = CS42L43_SPI_ROOT_HZ /
+				   cs42l43_clock_divs[ARRAY_SIZE(cs42l43_clock_divs) - 1];
+	priv->ctlr->max_speed_hz = CS42L43_SPI_ROOT_HZ / cs42l43_clock_divs[0];
+	priv->ctlr->use_gpio_descriptors = true;
+	priv->ctlr->auto_runtime_pm = true;
+
+	devm_pm_runtime_enable(priv->dev);
+	pm_runtime_idle(priv->dev);
+
+	regmap_write(priv->regmap, CS42L43_TRAN_CONFIG6, CS42L43_FIFO_SIZE - 1);
+	regmap_write(priv->regmap, CS42L43_TRAN_CONFIG7, CS42L43_FIFO_SIZE - 1);
+
+	// Disable Watchdog timer and enable stall
+	regmap_write(priv->regmap, CS42L43_SPI_CONFIG3, 0);
+	regmap_write(priv->regmap, CS42L43_SPI_CONFIG4, CS42L43_SPI_STALL_ENA_MASK);
+
+	ret = devm_spi_register_controller(priv->dev, priv->ctlr);
+	if (ret) {
+		pm_runtime_disable(priv->dev);
+		dev_err(priv->dev, "Failed to register SPI controller: %d\n", ret);
+	}
+
+	return ret;
+}
+
+static const struct platform_device_id cs42l43_spi_id_table[] = {
+	{ "cs42l43-spi", },
+	{}
+};
+MODULE_DEVICE_TABLE(platform, cs42l43_spi_id_table);
+
+static struct platform_driver cs42l43_spi_driver = {
+	.driver = {
+		.name	= "cs42l43-spi",
+	},
+	.probe		= cs42l43_spi_probe,
+	.id_table	= cs42l43_spi_id_table,
+};
+module_platform_driver(cs42l43_spi_driver);
+
+MODULE_DESCRIPTION("CS42L43 SPI Driver");
+MODULE_AUTHOR("Lucas Tanure <tanureal@opensource.cirrus.com>");
+MODULE_AUTHOR("Maciej Strozek <mstrozek@opensource.cirrus.com>");
+MODULE_LICENSE("GPL");