[RFC linux dev-4.7 2/5] drivers: i2c: Add FSI-attached I2C master algorithm
Eddie James
eajames at linux.vnet.ibm.com
Sat Mar 11 08:48:23 AEDT 2017
From: "Edward A. James" <eajames at us.ibm.com>
Initial startup code for the I2C algorithm to drive the I2C master
located on POWER CPUs over FSI bus.
Signed-off-by: Edward A. James <eajames at us.ibm.com>
---
drivers/Makefile | 2 +-
drivers/i2c/busses/Kconfig | 11 ++
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-fsi.c | 302 +++++++++++++++++++++++++++++++++++++++++++
4 files changed, 315 insertions(+), 1 deletion(-)
create mode 100644 drivers/i2c/busses/i2c-fsi.c
diff --git a/drivers/Makefile b/drivers/Makefile
index 26f18ac..b1db6d3 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -103,6 +103,7 @@ obj-$(CONFIG_SERIO) += input/serio/
obj-$(CONFIG_GAMEPORT) += input/gameport/
obj-$(CONFIG_INPUT) += input/
obj-$(CONFIG_RTC_LIB) += rtc/
+obj-$(CONFIG_FSI) += fsi/
obj-y += i2c/ media/
obj-$(CONFIG_PPS) += pps/
obj-$(CONFIG_PTP_1588_CLOCK) += ptp/
@@ -173,4 +174,3 @@ obj-$(CONFIG_STM) += hwtracing/stm/
obj-$(CONFIG_ANDROID) += android/
obj-$(CONFIG_NVMEM) += nvmem/
obj-$(CONFIG_FPGA) += fpga/
-obj-$(CONFIG_FSI) += fsi/
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 835480b..c248eded 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1210,4 +1210,15 @@ config I2C_OPAL
This driver can also be built as a module. If so, the module will be
called as i2c-opal.
+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 49631cd..b74b585 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -119,5 +119,6 @@ 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..c47cd234
--- /dev/null
+++ b/drivers/i2c/busses/i2c-fsi.c
@@ -0,0 +1,302 @@
+/*
+ * Copyright 2017 IBM Corporation
+ *
+ * Eddie James <eajames at 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/fsi.h>
+#include <linux/i2c.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/sched.h>
+
+#define FSI_ENGID_I2CM 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
+#define I2C_DEFAULT_CLK 333333
+#define I2C_ADDR_PORT 0xff00
+#define I2C_BOE_FIFO_HI_LVL 4
+#define I2C_BOE_FIFO_LO_LVL 4
+
+/* i2c registers */
+#define I2C_BOE_FIFO 0x00
+#define I2C_BOE_CMD 0x04
+#define I2C_BOE_MODE 0x08
+#define I2C_BOE_WATER_MARK 0x0C
+#define I2C_BOE_INT_MASK 0x10
+#define I2C_BOE_INT_COND 0x14
+#define I2C_BOE_OR_INT_MASK 0x14
+#define I2C_BOE_INTS 0x18
+#define I2C_BOE_AND_INT_MASK 0x18
+#define I2C_BOE_STAT 0x1C
+#define I2C_BOE_RESET_I2C 0x1C
+#define I2C_BOE_ESTAT 0x20
+#define I2C_BOE_RESET_ERR 0x20
+#define I2C_BOE_RESID_LEN 0x24
+#define I2C_BOE_SET_SCL 0x24
+#define I2C_BOE_PORT_BUSY 0x28
+#define I2C_BOE_RESET_SCL 0x2C
+#define I2C_BOE_SET_SDA 0x30
+#define I2C_BOE_RESET_SDA 0x34
+
+/* cmd register */
+#define I2C_BOE_CMD_WITH_START 0x80000000
+#define I2C_BOE_CMD_WITH_ADDR 0x40000000
+#define I2C_BOE_CMD_RD_CONT 0x20000000
+#define I2C_BOE_CMD_WITH_STOP 0x10000000
+#define I2C_BOE_CMD_FORCELAUNCH 0x08000000
+#define I2C_BOE_CMD_ADDR 0x00fe0000
+#define I2C_BOE_CMD_READ 0x00010000
+#define I2C_BOE_CMD_LEN 0x0000ffff
+
+/* mode register */
+#define I2C_BOE_MODE_CLKDIV 0xffff0000
+#define I2C_BOE_MODE_PORT 0x0000fc00
+#define I2C_BOE_MODE_ENHANCED 0x00000008
+#define I2C_BOE_MODE_DIAG 0x00000004
+#define I2C_BOE_MODE_PACE_ALLOW 0x00000002
+#define I2C_BOE_MODE_WRAP 0x00000001
+
+/* watermark register */
+#define I2C_BOE_WATERMARK_HI 0x0000f000
+#define I2C_BOE_WATERMARK_LO 0x000000f0
+
+/* interrupt register */
+#define I2C_BOE_INT_INV_CMD 0x00008000
+#define I2C_BOE_INT_PARITY 0x00004000
+#define I2C_BOE_INT_BE_OVERRUN 0x00002000
+#define I2C_BOE_INT_BE_ACCESS 0x00001000
+#define I2C_BOE_INT_LOST_ARB 0x00000800
+#define I2C_BOE_INT_NACK 0x00000400
+#define I2C_BOE_INT_DAT_REQ 0x00000200
+#define I2C_BOE_INT_CMD_COMP 0x00000100
+#define I2C_BOE_INT_STOP_ERR 0x00000080
+#define I2C_BOE_INT_BUSY 0x00000040
+#define I2C_BOE_INT_IDLE 0x00000020
+
+#define I2C_BOE_INT_ENABLE 0x0000ff80
+#define I2C_BOE_INT_ERR 0x0000fcc0
+
+/* status register */
+#define I2C_BOE_STAT_INV_CMD 0x80000000
+#define I2C_BOE_STAT_PARITY 0x40000000
+#define I2C_BOE_STAT_BE_OVERRUN 0x20000000
+#define I2C_BOE_STAT_BE_ACCESS 0x10000000
+#define I2C_BOE_STAT_LOST_ARB 0x08000000
+#define I2C_BOE_STAT_NACK 0x04000000
+#define I2C_BOE_STAT_DAT_REQ 0x02000000
+#define I2C_BOE_STAT_CMD_COMP 0x01000000
+#define I2C_BOE_STAT_STOP_ERR 0x00800000
+#define I2C_BOE_STAT_MAX_PORT 0x000f0000
+#define I2C_BOE_STAT_ANY_INT 0x00008000
+#define I2C_BOE_STAT_SCL_IN 0x00000800
+#define I2C_BOE_STAT_SDA_IN 0x00000400
+#define I2C_BOE_STAT_PORT_BUSY 0x00000200
+#define I2C_BOE_STAT_SELF_BUSY 0x00000100
+#define I2C_BOE_STAT_FIFO_COUNT 0x000000ff
+
+#define I2C_BOE_STAT_ERR 0xfc800000
+#define I2C_BOE_STAT_ANY_RESP 0xff800000
+
+/* extended status register */
+#define I2C_BOE_ESTAT_FIFO_SZ 0xff000000
+#define I2C_BOE_ESTAT_SCL_IN_SY 0x00008000
+#define I2C_BOE_ESTAT_SDA_IN_SY 0x00004000
+#define I2C_BOE_ESTAT_S_SCL 0x00002000
+#define I2C_BOE_ESTAT_S_SDA 0x00001000
+#define I2C_BOE_ESTAT_M_SCL 0x00000800
+#define I2C_BOE_ESTAT_M_SDA 0x00000400
+#define I2C_BOE_ESTAT_HI_WATER 0x00000200
+#define I2C_BOE_ESTAT_LO_WATER 0x00000100
+#define I2C_BOE_ESTAT_PORT_BUSY 0x00000080
+#define I2C_BOE_ESTAT_SELF_BUSY 0x00000040
+#define I2C_BOE_ESTAT_VERSION 0x0000001f
+
+struct fsi_i2c_bus {
+ struct i2c_adapter adapter;
+ struct fsi_device *fsi;
+ u8 fifo_size;
+ unsigned long clk;
+};
+
+static unsigned long fsi_i2c_get_clk_div(struct fsi_i2c_bus *i2c)
+{
+ unsigned long clk_div = I2C_DEFAULT_CLK_DIV;
+ unsigned long fsi_clk = fsi_device_get_clk_rate(i2c->fsi);
+
+ if (fsi_clk > i2c->clk)
+ clk_div = ((fsi_clk / i2c->clk) - 1) / 4;
+
+ return clk_div;
+}
+
+static int fsi_i2c_dev_init(struct fsi_i2c_bus *i2c)
+{
+ int rc;
+ unsigned long clk_div;
+ u32 mode = I2C_BOE_MODE_ENHANCED, extended_status, watermark = 0;
+ u32 interrupt = 0;
+
+ /* since we use polling, disable interrupts */
+ rc = fsi_device_write(i2c->fsi, I2C_BOE_INT_MASK, &interrupt,
+ sizeof(interrupt));
+ if (rc)
+ return rc;
+
+ clk_div = fsi_i2c_get_clk_div(i2c);
+ mode = SETFIELD(I2C_BOE_MODE_CLKDIV, mode, clk_div);
+ rc = fsi_device_write(i2c->fsi, I2C_BOE_MODE, &mode, sizeof(mode));
+ if (rc)
+ return rc;
+
+ rc = fsi_device_read(i2c->fsi, I2C_BOE_ESTAT, &extended_status,
+ sizeof(extended_status));
+ if (rc)
+ return rc;
+
+ i2c->fifo_size = GETFIELD(I2C_BOE_ESTAT_FIFO_SZ, extended_status);
+ watermark = SETFIELD(I2C_BOE_WATERMARK_HI, watermark,
+ i2c->fifo_size - I2C_BOE_FIFO_HI_LVL);
+ watermark = SETFIELD(I2C_BOE_WATERMARK_LO, watermark,
+ I2C_BOE_FIFO_LO_LVL);
+
+ rc = fsi_device_write(i2c->fsi, I2C_BOE_WATER_MARK, &watermark,
+ sizeof(watermark));
+
+ return rc;
+}
+
+static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ return -ENOSYS;
+}
+
+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 const char *compatible_strings[] = {
+ "ibm,power8-i2cm",
+ "ibm,power9-i2cm",
+};
+
+static int fsi_i2c_probe(struct device *dev)
+{
+ struct fsi_i2c_bus *i2c;
+ int rc, i;
+ struct device_node *np, *node = NULL;
+ u32 addr, clk;
+
+ i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ i2c->fsi = to_fsi_dev(dev);
+ i2c->clk = I2C_DEFAULT_CLK;
+
+ i2c->adapter.owner = THIS_MODULE;
+ i2c->adapter.dev.parent = dev;
+ i2c->adapter.algo = &fsi_i2c_algorithm;
+ i2c->adapter.algo_data = i2c;
+ strncpy(i2c->adapter.name, "power_i2cm", sizeof(i2c->adapter.name));
+
+ /* find node that matches FSI address */
+ for (i = 0; i < ARRAY_SIZE(compatible_strings) && !node; ++i) {
+ for_each_compatible_node(np, NULL, compatible_strings[i]) {
+ rc = of_property_read_u32(np, "reg", &addr);
+ if (rc)
+ continue;
+
+ if (addr == i2c->fsi->addr) {
+ node = np;
+ break;
+ }
+ }
+ }
+
+ if (node) {
+ rc = of_property_read_u32(node, "clock-frequency", &clk);
+ if (!rc)
+ i2c->clk = clk;
+ }
+
+ rc = fsi_i2c_dev_init(i2c);
+ if (rc)
+ return rc;
+
+ /* TODO: should we add an adapter for each port?? A lot of adapters...
+ * numbering isn't ideal either, automatically set to i2c-%d. So no
+ * way to distinguish fsi-i2c devs.
+ */
+ rc = i2c_add_adapter(&i2c->adapter);
+ if (rc < 0)
+ return rc;
+
+ dev_set_drvdata(dev, i2c);
+
+ return 0;
+}
+
+static int fsi_i2c_remove(struct device *dev)
+{
+ struct fsi_i2c_bus *i2c = dev_get_drvdata(dev);
+
+ i2c_del_adapter(&i2c->adapter);
+
+ return 0;
+}
+
+static const struct fsi_device_id fsi_i2c_ids[] = {
+ { FSI_ENGID_I2CM, FSI_VERSION_ANY },
+ { 0 }
+};
+
+static struct fsi_driver fsi_i2c_driver = {
+ .id_table = fsi_i2c_ids,
+ .drv = {
+ .name = "power_i2cm",
+ .bus = &fsi_bus_type,
+ .probe = fsi_i2c_probe,
+ .remove = fsi_i2c_remove,
+ },
+};
+
+static int fsi_i2c_init(void)
+{
+ return fsi_driver_register(&fsi_i2c_driver);
+}
+
+static void fsi_i2c_exit(void)
+{
+ fsi_driver_unregister(&fsi_i2c_driver);
+}
+
+module_init(fsi_i2c_init);
+module_exit(fsi_i2c_exit);
+
+MODULE_AUTHOR("Eddie James <eajames at us.ibm.com>");
+MODULE_DESCRIPTION("FSI attached I2C master");
+MODULE_LICENSE("GPL");
--
1.8.3.1
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