[PATCH 3/3] staging: jnx: pex8xxx I2C interface driver

From: Pantelis Antoniou
Date: Fri Oct 07 2016 - 11:19:45 EST

From: Rajat Jain <rajatjain@xxxxxxxxxxx>

Some Juniper platforms contain an Avago PEX8614, PEX8616 or PEX8713
PCI express switch which is controlled via a I2C interface.

This driver provides a sysfs interface for configuration from
user-space.

Signed-off-by: Guenter Roeck <groeck@xxxxxxxxxxx>
Signed-off-by: Rajat Jain <rajatjain@xxxxxxxxxxx>
[Ported from Juniper kernel]
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
---
drivers/staging/jnx/Kconfig | 7 +
drivers/staging/jnx/Makefile | 1 +
drivers/staging/jnx/pex8xxx_i2c.c | 509 ++++++++++++++++++++++++++++++++++++++
3 files changed, 517 insertions(+)
create mode 100644 drivers/staging/jnx/pex8xxx_i2c.c

diff --git a/drivers/staging/jnx/Kconfig b/drivers/staging/jnx/Kconfig
index 507f10d..b57e93b 100644
--- a/drivers/staging/jnx/Kconfig
+++ b/drivers/staging/jnx/Kconfig
@@ -33,4 +33,11 @@ config JNX_CHIP_PCI_QUIRKS
---help---
PCI quirks for the Juniper chips (ASICs, CPLDs, FPGAs)

+config JNX_PEX8XXX_I2C
+ tristate "PLX PEX8xxx switch I2C driver"
+ depends on I2C
+ ---help---
+ Driver for the I2C interface of PLX PEX8XXX devices
+ (Currently supports PEX8614, PEX8618, PEX8713)
+
endif # JNX_DEVICES
diff --git a/drivers/staging/jnx/Makefile b/drivers/staging/jnx/Makefile
index 0171476..90526b1 100644
--- a/drivers/staging/jnx/Makefile
+++ b/drivers/staging/jnx/Makefile
@@ -5,3 +5,4 @@
obj-$(CONFIG_JNX_SYSTEM) += jnx-subsys.o jnx-board-core.o
obj-$(CONFIG_JNX_CHIP_PCI_QUIRKS)+= jnx-chip-pci-quirks.o
obj-$(CONFIG_JNX_COMMON_PCI) += jnx_common_pci.o
+obj-$(CONFIG_JNX_PEX8XXX_I2C) += pex8xxx_i2c.o
diff --git a/drivers/staging/jnx/pex8xxx_i2c.c b/drivers/staging/jnx/pex8xxx_i2c.c
new file mode 100644
index 0000000..2414121
--- /dev/null
+++ b/drivers/staging/jnx/pex8xxx_i2c.c
@@ -0,0 +1,509 @@
+/*
+ * An I2C driver for the PEX8xxx I2C slave interface
+ *
+ * Rajat Jain <rajatjain@xxxxxxxxxxx>
+ * Copyright 2014 Juniper Networks
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/pci.h>
+#include <linux/jnx/pci_ids.h>
+
+/* Supported devices */
+enum chips { pex8614, pex8618, pex8713 };
+
+#define MAXSTN 2
+#define MAXMODE 4
+
+/* Common Register defines */
+#define PEX8XXX_CMD(val) (((val) & 7) << 24)
+#define PEX8XXX_CMD_WR 0x03
+#define PEX8XXX_CMD_RD 0x04
+
+#define PEX8XXX_BYTE_ENA(val) (((val) & 0xF) << 10)
+#define BYTE0 0x01
+#define BYTE1 0x02
+#define BYTE2 0x04
+#define BYTE3 0x08
+#define BYTE_ALL 0x0F
+
+#define PEX8XXX_REG(val) (((val) >> 2) & 0x3FF)
+
+/* PEX8614/8618 Device specific register defines */
+#define PEX861X_PORT(val) (((val) & 0x1F) << 15)
+
+#define PEX861X_I2C_CMD(cmd, port, mode, stn, reg, mask) \
+ (PEX8XXX_CMD(cmd) | \
+ PEX861X_PORT(port) | \
+ PEX8XXX_BYTE_ENA(mask) | \
+ PEX8XXX_REG(reg))
+
+/* PEX8713 Device specific register defines */
+#define PEX8713_MODE(val) (((val) & 3) << 20)
+#define PEX8713_MODE_TRANSPARENT 0x00
+#define PEX8713_MODE_NT_LINK 0x01
+#define PEX8713_MODE_NT_VIRT 0x02
+#define PEX8713_MODE_DMA 0x03
+
+#define PEX8713_STN(val) (((val) & 3) << 18)
+
+#define PEX8713_PORT(val) (((val) & 7) << 15)
+
+#define PEX8713_I2C_CMD(cmd, port, mode, stn, reg, mask) \
+ (PEX8XXX_CMD(cmd) | \
+ PEX8713_MODE(mode) | \
+ PEX8713_STN(stn) | \
+ PEX8713_PORT(port) | \
+ PEX8XXX_BYTE_ENA(mask) | \
+ PEX8XXX_REG(reg))
+
+struct pex8xxx_dev {
+ enum chips devtype;
+ u32 reg_addr;
+ u8 port_num;
+ u8 port_mode; /* PEX8713 only */
+ u8 port_stn; /* PEX8713 only */
+ struct attribute_group attr_group;
+ bool (*port_is_valid)(u8 port);
+};
+
+static inline struct pex8xxx_dev *pex8xxx_get_drvdata(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+
+ return i2c_get_clientdata(client);
+}
+
+static int pex8xxx_read(struct i2c_client *client, u8 stn, u8 mode, u8 mask,
+ u8 port, u32 reg, u32 *val)
+{
+ struct pex8xxx_dev *pex8xxx = i2c_get_clientdata(client);
+ __be32 cmd, data;
+ int ret;
+
+ struct i2c_msg msgs[2] = {
+ {
+ .addr = client->addr,
+ .len = 4,
+ .flags = 0,
+ .buf = (u8 *)&cmd,
+ },
+ {
+ .addr = client->addr,
+ .len = 4,
+ .flags = I2C_M_RD,
+ .buf = (u8 *)&data,
+ },
+ };
+
+ switch (pex8xxx->devtype) {
+ case pex8614:
+ case pex8618:
+ cmd = cpu_to_be32(PEX861X_I2C_CMD(PEX8XXX_CMD_RD, port, mode,
+ stn, reg, mask));
+ break;
+ case pex8713:
+ cmd = cpu_to_be32(PEX8713_I2C_CMD(PEX8XXX_CMD_RD, port, mode,
+ stn, reg, mask));
+ break;
+ default: /* Unknown device */
+ return -ENODEV;
+ }
+
+ ret = i2c_transfer(client->adapter, msgs, 2);
+ *val = be32_to_cpu(data);
+
+ if (ret < 0)
+ return ret;
+ else if (ret != ARRAY_SIZE(msgs))
+ return -EIO;
+
+ return 0;
+}
+
+static int pex8xxx_write(struct i2c_client *client, u8 stn, u8 mode, u8 mask,
+ u8 port, u32 reg, u32 val)
+{
+ struct pex8xxx_dev *pex8xxx = i2c_get_clientdata(client);
+ __be32 msgbuf[2];
+ int ret;
+
+ struct i2c_msg msg = {
+ .addr = client->addr,
+ .len = 8,
+ .flags = 0,
+ .buf = (u8 *)msgbuf,
+ };
+
+ switch (pex8xxx->devtype) {
+ case pex8614:
+ case pex8618:
+ msgbuf[0] = cpu_to_be32(PEX861X_I2C_CMD(PEX8XXX_CMD_WR, port,
+ mode, stn, reg, mask));
+ break;
+ case pex8713:
+ msgbuf[0] = cpu_to_be32(PEX8713_I2C_CMD(PEX8XXX_CMD_WR, port,
+ mode, stn, reg, mask));
+ break;
+ default: /* Unknown device */
+ return -ENODEV;
+ }
+ msgbuf[1] = cpu_to_be32(val);
+
+ ret = i2c_transfer(client->adapter, &msg, 1);
+
+ if (ret < 0)
+ return ret;
+ else if (ret != 1)
+ return -EIO;
+
+ return 0;
+}
+
+/*
+ * Different PCIe switch can have different port validators.
+ */
+static bool pex8618_port_is_valid(u8 port)
+{
+ return port <= 15;
+}
+
+static bool pex8713_port_is_valid(u8 port)
+{
+ return port <= 5 || (port >= 8 && port <= 13);
+}
+
+static bool pex8614_port_is_valid(u8 port)
+{
+ return port <= 2 ||
+ (port >= 4 && port <= 10) ||
+ port == 12 ||
+ port == 14;
+}
+
+static ssize_t port_num_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct pex8xxx_dev *pex8xxx = pex8xxx_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", pex8xxx->port_num);
+}
+
+static ssize_t port_num_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct pex8xxx_dev *pex8xxx = pex8xxx_get_drvdata(dev);
+ u8 port_num;
+
+ if (kstrtou8(buf, 0, &port_num))
+ return -EINVAL;
+
+ if (!pex8xxx->port_is_valid(port_num))
+ return -EINVAL;
+
+ pex8xxx->port_num = port_num;
+ return count;
+}
+static DEVICE_ATTR_RW(port_num);
+
+static ssize_t port_mode_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct pex8xxx_dev *pex8xxx = pex8xxx_get_drvdata(dev);
+ char *str;
+
+ switch (pex8xxx->port_mode) {
+ case PEX8713_MODE_TRANSPARENT:
+ str = "transparent";
+ break;
+ case PEX8713_MODE_NT_LINK:
+ str = "nt-link";
+ break;
+ case PEX8713_MODE_NT_VIRT:
+ str = "nt-virtual";
+ break;
+ case PEX8713_MODE_DMA:
+ str = "dma";
+ break;
+ default:
+ str = "unknown";
+ break;
+ }
+ return sprintf(buf, "%s\n", str);
+}
+
+static ssize_t port_mode_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct pex8xxx_dev *pex8xxx = pex8xxx_get_drvdata(dev);
+
+ if (!strcmp(buf, "transparent\n"))
+ pex8xxx->port_mode = PEX8713_MODE_TRANSPARENT;
+ else if (!strcmp(buf, "nt-link\n"))
+ pex8xxx->port_mode = PEX8713_MODE_NT_LINK;
+ else if (!strcmp(buf, "nt-virtual\n"))
+ pex8xxx->port_mode = PEX8713_MODE_NT_VIRT;
+ else if (!strcmp(buf, "dma\n"))
+ pex8xxx->port_mode = PEX8713_MODE_DMA;
+ else
+ return -EINVAL;
+
+ return count;
+}
+static DEVICE_ATTR_RW(port_mode);
+
+static ssize_t port_stn_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct pex8xxx_dev *pex8xxx = pex8xxx_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", pex8xxx->port_stn);
+}
+
+static ssize_t port_stn_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct pex8xxx_dev *pex8xxx = pex8xxx_get_drvdata(dev);
+ u8 stn;
+
+ if (kstrtou8(buf, 0, &stn) || (stn >= MAXSTN))
+ return -EINVAL;
+
+ pex8xxx->port_stn = stn;
+
+ return count;
+}
+static DEVICE_ATTR_RW(port_stn);
+
+static ssize_t reg_addr_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct pex8xxx_dev *pex8xxx = pex8xxx_get_drvdata(dev);
+
+ return sprintf(buf, "0x%X\n", pex8xxx->reg_addr);
+}
+
+static ssize_t reg_addr_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct pex8xxx_dev *pex8xxx = pex8xxx_get_drvdata(dev);
+ unsigned long reg_addr;
+
+ /* PEX8xxx devices support 4K memory per port */
+ if (kstrtoul(buf, 0, &reg_addr) || reg_addr >= 4096 || reg_addr % 4)
+ return -EINVAL;
+
+ pex8xxx->reg_addr = reg_addr;
+
+ return count;
+}
+static DEVICE_ATTR_RW(reg_addr);
+
+static ssize_t reg_value_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct pex8xxx_dev *pex8xxx;
+ struct i2c_client *client;
+ u32 regval = 0;
+ int ret;
+
+ client = to_i2c_client(dev);
+ pex8xxx = i2c_get_clientdata(client);
+
+ ret = pex8xxx_read(client, pex8xxx->port_stn, pex8xxx->port_mode,
+ BYTE_ALL, pex8xxx->port_num, pex8xxx->reg_addr,
+ &regval);
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "0x%08X\n", regval);
+}
+
+static ssize_t reg_value_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct pex8xxx_dev *pex8xxx;
+ struct i2c_client *client;
+ unsigned long reg_val;
+ int retval;
+
+ client = to_i2c_client(dev);
+ pex8xxx = i2c_get_clientdata(client);
+
+ if (kstrtoul(buf, 0, &reg_val))
+ return -EINVAL;
+
+ retval = pex8xxx_write(client, pex8xxx->port_stn, pex8xxx->port_mode,
+ BYTE_ALL, pex8xxx->port_num, pex8xxx->reg_addr,
+ reg_val);
+ if (retval)
+ return retval;
+
+ return count;
+}
+static DEVICE_ATTR_RW(reg_value);
+
+static ssize_t
+port_config_regs_read_bin(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ unsigned int size = 4096;
+ loff_t init_off = off;
+ u32 *buf32 = (u32 *)buf;
+ u32 regval;
+ int ret;
+
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct i2c_client *client = to_i2c_client(dev);
+ struct pex8xxx_dev *pex8xxx = i2c_get_clientdata(client);
+
+ if (off > size || off & 3)
+ return 0;
+ if (off + count > size) {
+ size -= off;
+ count = size;
+ } else {
+ size = count;
+ }
+
+ while (size) {
+ ret = pex8xxx_read(client, pex8xxx->port_stn,
+ pex8xxx->port_mode, BYTE_ALL,
+ pex8xxx->port_num, off, &regval);
+ if (ret)
+ regval = 0xDEADBEEF;
+
+ buf32[(off - init_off) / 4] = regval;
+ off += 4;
+ size -= 4;
+ }
+
+ return count;
+}
+static BIN_ATTR(port_config_regs, S_IRUGO, port_config_regs_read_bin,
+ NULL, 4096);
+
+static struct attribute *pex861x_attrs[] = {
+ &dev_attr_port_num.attr,
+ &dev_attr_reg_addr.attr,
+ &dev_attr_reg_value.attr,
+ NULL,
+};
+
+static struct attribute *pex8713_attrs[] = {
+ &dev_attr_port_num.attr,
+ &dev_attr_port_mode.attr,
+ &dev_attr_port_stn.attr,
+ &dev_attr_reg_addr.attr,
+ &dev_attr_reg_value.attr,
+ NULL,
+};
+
+static struct bin_attribute *pex8xxx_bin_attrs[] = {
+ &bin_attr_port_config_regs,
+ NULL,
+};
+
+static int pex8xxx_verify_device(struct pex8xxx_dev *pex8xxx,
+ struct i2c_client *client)
+{
+ u8 stn, mode;
+ bool found = false;
+ u32 data = 0;
+
+ for (stn = 0; stn < MAXSTN; stn++) {
+ for (mode = 0; mode < MAXMODE; mode++) {
+ if (!pex8xxx_read(client, stn, mode, BYTE_ALL, 0,
+ PCI_VENDOR_ID, &data)) {
+ found = true;
+ break;
+ }
+ }
+ }
+
+ if (!found || (data & 0xFFFF) != PCI_VENDOR_ID_PLX)
+ return -ENODEV;
+
+ switch (data >> 16) {
+ case PCI_DEVICE_ID_PLX_8614:
+ pex8xxx->devtype = pex8614;
+ pex8xxx->port_is_valid = pex8614_port_is_valid;
+ pex8xxx->attr_group.attrs = pex861x_attrs;
+ break;
+ case PCI_DEVICE_ID_PLX_8618:
+ pex8xxx->devtype = pex8618;
+ pex8xxx->port_is_valid = pex8618_port_is_valid;
+ pex8xxx->attr_group.attrs = pex861x_attrs;
+ break;
+ case PCI_DEVICE_ID_PLX_8713:
+ pex8xxx->devtype = pex8713;
+ pex8xxx->port_is_valid = pex8713_port_is_valid;
+ pex8xxx->attr_group.attrs = pex8713_attrs;
+ break;
+ default: /* Unsupported PLX device */
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static int pex8xxx_probe(struct i2c_client *client,
+ const struct i2c_device_id *dev_id)
+{
+ struct pex8xxx_dev *pex8xxx;
+ int retval;
+
+ pex8xxx = devm_kzalloc(&client->dev, sizeof(*pex8xxx), GFP_KERNEL);
+ if (!pex8xxx)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, pex8xxx);
+
+ if (pex8xxx_verify_device(pex8xxx, client))
+ return -ENODEV;
+
+ pex8xxx->attr_group.bin_attrs = pex8xxx_bin_attrs;
+
+ retval = sysfs_create_group(&client->dev.kobj, &pex8xxx->attr_group);
+
+ return retval;
+}
+
+static int pex8xxx_remove(struct i2c_client *client)
+{
+ struct pex8xxx_dev *pex8xxx = i2c_get_clientdata(client);
+
+ sysfs_remove_group(&client->dev.kobj, &pex8xxx->attr_group);
+ return 0;
+}
+
+static const struct i2c_device_id pex8xxx_id[] = {
+ { "pex8614", pex8614 },
+ { "pex8618", pex8618 },
+ { "pex8713", pex8713 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, pex8xxx_id);
+
+static struct i2c_driver pex8xxx_driver = {
+ .driver = {
+ .name = "pex8xxx",
+ },
+ .probe = pex8xxx_probe,
+ .remove = pex8xxx_remove,
+ .id_table = pex8xxx_id,
+};
+
+module_i2c_driver(pex8xxx_driver);
+
+MODULE_DESCRIPTION("PLX PEX8xxx switch I2C interface driver");
+MODULE_AUTHOR("Rajat Jain <rajatjain@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
1.9.1