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-rw-r--r--drivers/mfd/tps6594-i2c.c244
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/mfd/tps6594-i2c.c b/drivers/mfd/tps6594-i2c.c
new file mode 100644
index 0000000000..899c88c0fe
--- /dev/null
+++ b/drivers/mfd/tps6594-i2c.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * I2C access driver for TI TPS6594/TPS6593/LP8764 PMICs
+ *
+ * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/
+ */
+
+#include <linux/crc8.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+#include <linux/mfd/tps6594.h>
+
+static bool enable_crc;
+module_param(enable_crc, bool, 0444);
+MODULE_PARM_DESC(enable_crc, "Enable CRC feature for I2C interface");
+
+DECLARE_CRC8_TABLE(tps6594_i2c_crc_table);
+
+static int tps6594_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+ int ret = i2c_transfer(adap, msgs, num);
+
+ if (ret == num)
+ return 0;
+ else if (ret < 0)
+ return ret;
+ else
+ return -EIO;
+}
+
+static int tps6594_i2c_reg_read_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 *val)
+{
+ struct i2c_msg msgs[2];
+ u8 buf_rx[] = { 0, 0 };
+ /* I2C address = I2C base address + Page index */
+ const u8 addr = client->addr + page;
+ /*
+ * CRC is calculated from every bit included in the protocol
+ * except the ACK bits from the target. Byte stream is:
+ * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0
+ * - B1: reg
+ * - B2: (I2C_addr_7bits << 1) | RD_bit, with RD_bit = 1
+ * - B3: val
+ * - B4: CRC from B0-B1-B2-B3
+ */
+ u8 crc_data[] = { addr << 1, reg, addr << 1 | 1, 0 };
+ int ret;
+
+ /* Write register */
+ msgs[0].addr = addr;
+ msgs[0].flags = 0;
+ msgs[0].len = 1;
+ msgs[0].buf = &reg;
+
+ /* Read data and CRC */
+ msgs[1].addr = msgs[0].addr;
+ msgs[1].flags = I2C_M_RD;
+ msgs[1].len = 2;
+ msgs[1].buf = buf_rx;
+
+ ret = tps6594_i2c_transfer(client->adapter, msgs, 2);
+ if (ret < 0)
+ return ret;
+
+ crc_data[sizeof(crc_data) - 1] = *val = buf_rx[0];
+ if (buf_rx[1] != crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE))
+ return -EIO;
+
+ return ret;
+}
+
+static int tps6594_i2c_reg_write_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 val)
+{
+ struct i2c_msg msg;
+ u8 buf[] = { reg, val, 0 };
+ /* I2C address = I2C base address + Page index */
+ const u8 addr = client->addr + page;
+ /*
+ * CRC is calculated from every bit included in the protocol
+ * except the ACK bits from the target. Byte stream is:
+ * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0
+ * - B1: reg
+ * - B2: val
+ * - B3: CRC from B0-B1-B2
+ */
+ const u8 crc_data[] = { addr << 1, reg, val };
+
+ /* Write register, data and CRC */
+ msg.addr = addr;
+ msg.flags = client->flags & I2C_M_TEN;
+ msg.len = sizeof(buf);
+ msg.buf = buf;
+
+ buf[msg.len - 1] = crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE);
+
+ return tps6594_i2c_transfer(client->adapter, &msg, 1);
+}
+
+static int tps6594_i2c_read(void *context, const void *reg_buf, size_t reg_size,
+ void *val_buf, size_t val_size)
+{
+ struct i2c_client *client = context;
+ struct tps6594 *tps = i2c_get_clientdata(client);
+ struct i2c_msg msgs[2];
+ const u8 *reg_bytes = reg_buf;
+ u8 *val_bytes = val_buf;
+ const u8 page = reg_bytes[1];
+ u8 reg = reg_bytes[0];
+ int ret = 0;
+ int i;
+
+ if (tps->use_crc) {
+ /*
+ * Auto-increment feature does not support CRC protocol.
+ * Converts the bulk read operation into a series of single read operations.
+ */
+ for (i = 0 ; ret == 0 && i < val_size ; i++)
+ ret = tps6594_i2c_reg_read_with_crc(client, page, reg + i, val_bytes + i);
+
+ return ret;
+ }
+
+ /* Write register: I2C address = I2C base address + Page index */
+ msgs[0].addr = client->addr + page;
+ msgs[0].flags = 0;
+ msgs[0].len = 1;
+ msgs[0].buf = &reg;
+
+ /* Read data */
+ msgs[1].addr = msgs[0].addr;
+ msgs[1].flags = I2C_M_RD;
+ msgs[1].len = val_size;
+ msgs[1].buf = val_bytes;
+
+ return tps6594_i2c_transfer(client->adapter, msgs, 2);
+}
+
+static int tps6594_i2c_write(void *context, const void *data, size_t count)
+{
+ struct i2c_client *client = context;
+ struct tps6594 *tps = i2c_get_clientdata(client);
+ struct i2c_msg msg;
+ const u8 *bytes = data;
+ u8 *buf;
+ const u8 page = bytes[1];
+ const u8 reg = bytes[0];
+ int ret = 0;
+ int i;
+
+ if (tps->use_crc) {
+ /*
+ * Auto-increment feature does not support CRC protocol.
+ * Converts the bulk write operation into a series of single write operations.
+ */
+ for (i = 0 ; ret == 0 && i < count - 2 ; i++)
+ ret = tps6594_i2c_reg_write_with_crc(client, page, reg + i, bytes[i + 2]);
+
+ return ret;
+ }
+
+ /* Setup buffer: page byte is not sent */
+ buf = kzalloc(--count, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ buf[0] = reg;
+ for (i = 0 ; i < count - 1 ; i++)
+ buf[i + 1] = bytes[i + 2];
+
+ /* Write register and data: I2C address = I2C base address + Page index */
+ msg.addr = client->addr + page;
+ msg.flags = client->flags & I2C_M_TEN;
+ msg.len = count;
+ msg.buf = buf;
+
+ ret = tps6594_i2c_transfer(client->adapter, &msg, 1);
+
+ kfree(buf);
+ return ret;
+}
+
+static const struct regmap_config tps6594_i2c_regmap_config = {
+ .reg_bits = 16,
+ .val_bits = 8,
+ .max_register = TPS6594_REG_DWD_FAIL_CNT_REG,
+ .volatile_reg = tps6594_is_volatile_reg,
+ .read = tps6594_i2c_read,
+ .write = tps6594_i2c_write,
+};
+
+static const struct of_device_id tps6594_i2c_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_i2c_of_match_table);
+
+static int tps6594_i2c_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct tps6594 *tps;
+ const struct of_device_id *match;
+
+ tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL);
+ if (!tps)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, tps);
+
+ tps->dev = dev;
+ tps->reg = client->addr;
+ tps->irq = client->irq;
+
+ tps->regmap = devm_regmap_init(dev, NULL, client, &tps6594_i2c_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_i2c_of_match_table, dev);
+ if (!match)
+ return dev_err_probe(dev, -EINVAL, "Failed to find matching chip ID\n");
+ tps->chip_id = (unsigned long)match->data;
+
+ crc8_populate_msb(tps6594_i2c_crc_table, TPS6594_CRC8_POLYNOMIAL);
+
+ return tps6594_device_init(tps, enable_crc);
+}
+
+static struct i2c_driver tps6594_i2c_driver = {
+ .driver = {
+ .name = "tps6594",
+ .of_match_table = tps6594_i2c_of_match_table,
+ },
+ .probe = tps6594_i2c_probe,
+};
+module_i2c_driver(tps6594_i2c_driver);
+
+MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");
+MODULE_DESCRIPTION("TPS6594 I2C Interface Driver");
+MODULE_LICENSE("GPL");