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// 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_host(&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) {
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");
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