mfd: tps6594: Add driver for TI TPS6594 PMIC

This patch adds support for TPS6594 PMIC MFD core. It provides
communication through the I2C and SPI interfaces, and supports
protocols with embedded CRC data fields for safety applications.

Signed-off-by: Julien Panis <jpanis@baylibre.com>
Link: https://lore.kernel.org/r/20230511095126.105104-3-jpanis@baylibre.com
Signed-off-by: Lee Jones <lee@kernel.org>

1 files changed, 129 insertions, 0 deletions

diff --git a/drivers/mfd/tps6594-spi.c b/drivers/mfd/tps6594-spi.c
new file mode 100644
index 000000000000..a938a191744f
--- /dev/null
+++ b/drivers/mfd/tps6594-spi.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SPI access driver for TI TPS6594/TPS6593/LP8764 PMICs
+ *
+ * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/
+ */
+
+#include <linux/crc8.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include <linux/mfd/tps6594.h>
+
+#define TPS6594_SPI_PAGE_SHIFT	5
+#define TPS6594_SPI_READ_BIT	BIT(4)
+
+static bool enable_crc;
+module_param(enable_crc, bool, 0444);
+MODULE_PARM_DESC(enable_crc, "Enable CRC feature for SPI interface");
+
+DECLARE_CRC8_TABLE(tps6594_spi_crc_table);
+
+static int tps6594_spi_reg_read(void *context, unsigned int reg, unsigned int *val)
+{
+	struct spi_device *spi = context;
+	struct tps6594 *tps = spi_get_drvdata(spi);
+	u8 buf[4] = { 0 };
+	size_t count_rx = 1;
+	int ret;
+
+	buf[0] = reg;
+	buf[1] = TPS6594_REG_TO_PAGE(reg) << TPS6594_SPI_PAGE_SHIFT | TPS6594_SPI_READ_BIT;
+
+	if (tps->use_crc)
+		count_rx++;
+
+	ret = spi_write_then_read(spi, buf, 2, buf + 2, count_rx);
+	if (ret < 0)
+		return ret;
+
+	if (tps->use_crc && buf[3] != crc8(tps6594_spi_crc_table, buf, 3, CRC8_INIT_VALUE))
+		return -EIO;
+
+	*val = buf[2];
+
+	return 0;
+}
+
+static int tps6594_spi_reg_write(void *context, unsigned int reg, unsigned int val)
+{
+	struct spi_device *spi = context;
+	struct tps6594 *tps = spi_get_drvdata(spi);
+	u8 buf[4] = { 0 };
+	size_t count = 3;
+
+	buf[0] = reg;
+	buf[1] = TPS6594_REG_TO_PAGE(reg) << TPS6594_SPI_PAGE_SHIFT;
+	buf[2] = val;
+
+	if (tps->use_crc)
+		buf[3] = crc8(tps6594_spi_crc_table, buf, count++, CRC8_INIT_VALUE);
+
+	return spi_write(spi, buf, count);
+}
+
+static const struct regmap_config tps6594_spi_regmap_config = {
+	.reg_bits = 16,
+	.val_bits = 8,
+	.max_register = TPS6594_REG_DWD_FAIL_CNT_REG,
+	.volatile_reg = tps6594_is_volatile_reg,
+	.reg_read = tps6594_spi_reg_read,
+	.reg_write = tps6594_spi_reg_write,
+	.use_single_read = true,
+	.use_single_write = true,
+};
+
+static const struct of_device_id tps6594_spi_of_match_table[] = {
+	{ .compatible = "ti,tps6594-q1", .data = (void *)TPS6594, },
+	{ .compatible = "ti,tps6593-q1", .data = (void *)TPS6593, },
+	{ .compatible = "ti,lp8764-q1",  .data = (void *)LP8764,  },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tps6594_spi_of_match_table);
+
+static int tps6594_spi_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct tps6594 *tps;
+	const struct of_device_id *match;
+
+	tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL);
+	if (!tps)
+		return -ENOMEM;
+
+	spi_set_drvdata(spi, tps);
+
+	tps->dev = dev;
+	tps->reg = spi->chip_select;
+	tps->irq = spi->irq;
+
+	tps->regmap = devm_regmap_init(dev, NULL, spi, &tps6594_spi_regmap_config);
+	if (IS_ERR(tps->regmap))
+		return dev_err_probe(dev, PTR_ERR(tps->regmap), "Failed to init regmap\n");
+
+	match = of_match_device(tps6594_spi_of_match_table, dev);
+	if (!match)
+		return dev_err_probe(dev, PTR_ERR(match), "Failed to find matching chip ID\n");
+	tps->chip_id = (unsigned long)match->data;
+
+	crc8_populate_msb(tps6594_spi_crc_table, TPS6594_CRC8_POLYNOMIAL);
+
+	return tps6594_device_init(tps, enable_crc);
+}
+
+static struct spi_driver tps6594_spi_driver = {
+	.driver	= {
+		.name = "tps6594",
+		.of_match_table = tps6594_spi_of_match_table,
+	},
+	.probe = tps6594_spi_probe,
+};
+module_spi_driver(tps6594_spi_driver);
+
+MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");
+MODULE_DESCRIPTION("TPS6594 SPI Interface Driver");
+MODULE_LICENSE("GPL");