[PATCH v6 5/6] spi: cs42l43: Add SPI controller support

[Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>]

From: Lucas Tanure <tanureal@xxxxxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Maciej Strozek <mstrozek@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
---

Changes since v5:
  - Correct the SPI base clock back to 40MHz it was mistakenly changed to
    4MHz when switching to HZ_PER_MHZ.
  - Switch back to regmap_read and write rather than raw read, we
    actually need the normal operations. Since the FIFO is represented
    in the device as 32bit registers and the I2C and SDW control
    buses actually present the device as a different endian we need
    the endian handling of regmap.

Thanks,
Charles


 MAINTAINERS               |   1 +
 drivers/spi/Kconfig       |   7 +
 drivers/spi/Makefile      |   1 +
 drivers/spi/spi-cs42l43.c | 284 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 293 insertions(+)
 create mode 100644 drivers/spi/spi-cs42l43.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 4e35a4880cf84..5a581e846537d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4881,6 +4881,7 @@ 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*
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 8962b25576156..083f71cf4829f 100644
--- a/drivers/spi/Kconfig
+++ b/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
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 080c2c1b3ec19..c537640bed701 100644
--- a/drivers/spi/Makefile
+++ b/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
diff --git a/drivers/spi/spi-cs42l43.c b/drivers/spi/spi-cs42l43.c
new file mode 100644
index 0000000000000..453a9b37ce785
--- /dev/null
+++ b/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@xxxxxxxxxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Maciej Strozek <mstrozek@xxxxxxxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
-- 
2.30.2