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Subject[PATCH v4 1/6] drivers/i2c: Add FSI-attached I2C master algorithm
Date
From: "Edward A. James" <eajames@us.ibm.com>

Add register definitions for FSI-attached I2C master and functions to
access those registers over FSI. Add an FSI driver so that our I2C bus
is probed up during an FSI scan.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
---
drivers/i2c/busses/Kconfig | 11 ++
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-fsi.c | 243 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 255 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-fsi.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 1006b23..07503b4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1290,4 +1290,15 @@ config I2C_ZX2967
This driver can also be built as a module. If so, the module will be
called i2c-zx2967.

+config I2C_FSI
+ tristate "FSI I2C driver"
+ depends on FSI
+ help
+ Driver for FSI bus attached I2C masters. These are I2C masters that
+ are connected to the system over a FSI bus, instead of the more
+ common PCI or MMIO interface.
+
+ This driver can also be built as a module. If so, the module will be
+ called as i2c-fsi.
+
endmenu
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 1b2fc81..aa5f7b5 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -131,5 +131,6 @@ obj-$(CONFIG_I2C_PCA_ISA) += i2c-pca-isa.o
obj-$(CONFIG_I2C_SIBYTE) += i2c-sibyte.o
obj-$(CONFIG_I2C_XGENE_SLIMPRO) += i2c-xgene-slimpro.o
obj-$(CONFIG_SCx200_ACB) += scx200_acb.o
+obj-$(CONFIG_I2C_FSI) += i2c-fsi.o

ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c
new file mode 100644
index 0000000..b7f2bc6
--- /dev/null
+++ b/drivers/i2c/busses/i2c-fsi.c
@@ -0,0 +1,243 @@
+/*
+ * Copyright 2017 IBM Corporation
+ *
+ * Eddie James <eajames@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/fsi.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#define FSI_ENGID_I2C 0x7
+
+/* Find left shift from first set bit in m */
+#define MASK_TO_LSH(m) (__builtin_ffsll(m) - 1ULL)
+
+/* Extract field m from v */
+#define GETFIELD(m, v) (((v) & (m)) >> MASK_TO_LSH(m))
+
+/* Set field m of v to val */
+#define SETFIELD(m, v, val) \
+ (((v) & ~(m)) | ((((typeof(v))(val)) << MASK_TO_LSH(m)) & (m)))
+
+#define I2C_DEFAULT_CLK_DIV 6
+
+/* i2c registers */
+#define I2C_FSI_FIFO 0x00
+#define I2C_FSI_CMD 0x04
+#define I2C_FSI_MODE 0x08
+#define I2C_FSI_WATER_MARK 0x0C
+#define I2C_FSI_INT_MASK 0x10
+#define I2C_FSI_INT_COND 0x14
+#define I2C_FSI_OR_INT_MASK 0x14
+#define I2C_FSI_INTS 0x18
+#define I2C_FSI_AND_INT_MASK 0x18
+#define I2C_FSI_STAT 0x1C
+#define I2C_FSI_RESET_I2C 0x1C
+#define I2C_FSI_ESTAT 0x20
+#define I2C_FSI_RESET_ERR 0x20
+#define I2C_FSI_RESID_LEN 0x24
+#define I2C_FSI_SET_SCL 0x24
+#define I2C_FSI_PORT_BUSY 0x28
+#define I2C_FSI_RESET_SCL 0x2C
+#define I2C_FSI_SET_SDA 0x30
+#define I2C_FSI_RESET_SDA 0x34
+
+/* cmd register */
+#define I2C_CMD_WITH_START 0x80000000
+#define I2C_CMD_WITH_ADDR 0x40000000
+#define I2C_CMD_RD_CONT 0x20000000
+#define I2C_CMD_WITH_STOP 0x10000000
+#define I2C_CMD_FORCELAUNCH 0x08000000
+#define I2C_CMD_ADDR 0x00fe0000
+#define I2C_CMD_READ 0x00010000
+#define I2C_CMD_LEN 0x0000ffff
+
+/* mode register */
+#define I2C_MODE_CLKDIV 0xffff0000
+#define I2C_MODE_PORT 0x0000fc00
+#define I2C_MODE_ENHANCED 0x00000008
+#define I2C_MODE_DIAG 0x00000004
+#define I2C_MODE_PACE_ALLOW 0x00000002
+#define I2C_MODE_WRAP 0x00000001
+
+/* watermark register */
+#define I2C_WATERMARK_HI 0x0000f000
+#define I2C_WATERMARK_LO 0x000000f0
+
+#define I2C_FIFO_HI_LVL 4
+#define I2C_FIFO_LO_LVL 4
+
+/* interrupt register */
+#define I2C_INT_INV_CMD 0x00008000
+#define I2C_INT_PARITY 0x00004000
+#define I2C_INT_BE_OVERRUN 0x00002000
+#define I2C_INT_BE_ACCESS 0x00001000
+#define I2C_INT_LOST_ARB 0x00000800
+#define I2C_INT_NACK 0x00000400
+#define I2C_INT_DAT_REQ 0x00000200
+#define I2C_INT_CMD_COMP 0x00000100
+#define I2C_INT_STOP_ERR 0x00000080
+#define I2C_INT_BUSY 0x00000040
+#define I2C_INT_IDLE 0x00000020
+
+#define I2C_INT_ENABLE 0x0000ff80
+#define I2C_INT_ERR 0x0000fcc0
+
+/* status register */
+#define I2C_STAT_INV_CMD 0x80000000
+#define I2C_STAT_PARITY 0x40000000
+#define I2C_STAT_BE_OVERRUN 0x20000000
+#define I2C_STAT_BE_ACCESS 0x10000000
+#define I2C_STAT_LOST_ARB 0x08000000
+#define I2C_STAT_NACK 0x04000000
+#define I2C_STAT_DAT_REQ 0x02000000
+#define I2C_STAT_CMD_COMP 0x01000000
+#define I2C_STAT_STOP_ERR 0x00800000
+#define I2C_STAT_MAX_PORT 0x000f0000
+#define I2C_STAT_ANY_INT 0x00008000
+#define I2C_STAT_SCL_IN 0x00000800
+#define I2C_STAT_SDA_IN 0x00000400
+#define I2C_STAT_PORT_BUSY 0x00000200
+#define I2C_STAT_SELF_BUSY 0x00000100
+#define I2C_STAT_FIFO_COUNT 0x000000ff
+
+#define I2C_STAT_ERR 0xfc800000
+#define I2C_STAT_ANY_RESP 0xff800000
+
+/* extended status register */
+#define I2C_ESTAT_FIFO_SZ 0xff000000
+#define I2C_ESTAT_SCL_IN_SY 0x00008000
+#define I2C_ESTAT_SDA_IN_SY 0x00004000
+#define I2C_ESTAT_S_SCL 0x00002000
+#define I2C_ESTAT_S_SDA 0x00001000
+#define I2C_ESTAT_M_SCL 0x00000800
+#define I2C_ESTAT_M_SDA 0x00000400
+#define I2C_ESTAT_HI_WATER 0x00000200
+#define I2C_ESTAT_LO_WATER 0x00000100
+#define I2C_ESTAT_PORT_BUSY 0x00000080
+#define I2C_ESTAT_SELF_BUSY 0x00000040
+#define I2C_ESTAT_VERSION 0x0000001f
+
+struct fsi_i2c_master {
+ struct fsi_device *fsi;
+ u8 fifo_size;
+};
+
+static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg,
+ u32 *data)
+{
+ int rc;
+ __be32 data_be;
+
+ rc = fsi_device_read(fsi, reg, &data_be, sizeof(data_be));
+ if (rc)
+ return rc;
+
+ *data = be32_to_cpu(data_be);
+
+ return 0;
+}
+
+static int fsi_i2c_write_reg(struct fsi_device *fsi, unsigned int reg,
+ u32 *data)
+{
+ __be32 data_be = cpu_to_be32(*data);
+
+ return fsi_device_write(fsi, reg, &data_be, sizeof(data_be));
+}
+
+static int fsi_i2c_dev_init(struct fsi_i2c_master *i2c)
+{
+ int rc;
+ u32 mode = I2C_MODE_ENHANCED, extended_status, watermark = 0;
+ u32 interrupt = 0;
+
+ /* since we use polling, disable interrupts */
+ rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_INT_MASK, &interrupt);
+ if (rc)
+ return rc;
+
+ mode = SETFIELD(I2C_MODE_CLKDIV, mode, I2C_DEFAULT_CLK_DIV);
+ rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode);
+ if (rc)
+ return rc;
+
+ rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_ESTAT, &extended_status);
+ if (rc)
+ return rc;
+
+ i2c->fifo_size = GETFIELD(I2C_ESTAT_FIFO_SZ, extended_status);
+ watermark = SETFIELD(I2C_WATERMARK_HI, watermark,
+ i2c->fifo_size - I2C_FIFO_HI_LVL);
+ watermark = SETFIELD(I2C_WATERMARK_LO, watermark,
+ I2C_FIFO_LO_LVL);
+
+ rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_WATER_MARK, &watermark);
+
+ return rc;
+}
+
+static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ return -EOPNOTSUPP;
+}
+
+static u32 fsi_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_10BIT_ADDR;
+}
+
+static const struct i2c_algorithm fsi_i2c_algorithm = {
+ .master_xfer = fsi_i2c_xfer,
+ .functionality = fsi_i2c_functionality,
+};
+
+static int fsi_i2c_probe(struct device *dev)
+{
+ struct fsi_i2c_master *i2c;
+ int rc;
+
+ i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ i2c->fsi = to_fsi_dev(dev);
+
+ rc = fsi_i2c_dev_init(i2c);
+ if (rc)
+ return rc;
+
+ dev_set_drvdata(dev, i2c);
+
+ return 0;
+}
+
+static const struct fsi_device_id fsi_i2c_ids[] = {
+ { FSI_ENGID_I2C, FSI_VERSION_ANY },
+ { 0 }
+};
+
+static struct fsi_driver fsi_i2c_driver = {
+ .id_table = fsi_i2c_ids,
+ .drv = {
+ .name = "i2c-fsi",
+ .bus = &fsi_bus_type,
+ .probe = fsi_i2c_probe,
+ },
+};
+
+module_fsi_driver(fsi_i2c_driver);
+
+MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>");
+MODULE_DESCRIPTION("FSI attached I2C master");
+MODULE_LICENSE("GPL");
--
1.8.3.1
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