This bus driver supports the Single-wire Serial Bus Interface (SSBI)
controller in the Qualcomm MSM SOCs. SSBI is not an I2C but is
functionally related enough such that it is able to leverage the I2C
framework.
Unlike I2C, SSBI is a point-to-point connection, and therefore there is no
need to specify a slave device address. The SSBI implementation
overrides the slave device address to be a device register address
instead. This restricts the client drivers from using the SMBus
communication APIs unless they update the address field (addr) of the
i2c_client structure prior to every SMBus function call. Instead it is
recommended to use the i2c_transfer function where the address is
specified as part of the i2c_msg structure. The i2c_transfer function
also provides more flexibility for performing multiple transactions in a
single function call.
Signed-off-by: Kenneth Heitke<kheitke@xxxxxxxxxxxxxx>
---
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-ssbi.c | 472 +++++++++++++++++++++++++++++++++++++++++
include/linux/i2c-ssbi.h | 33 +++
4 files changed, 516 insertions(+), 0 deletions(-)
create mode 100644 drivers/i2c/busses/i2c-ssbi.c
create mode 100755 include/linux/i2c-ssbi.h
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index bceafbf..690d601 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -569,6 +569,16 @@ config I2C_SIMTEC
This driver can also be built as a module. If so, the module
will be called i2c-simtec.
+config I2C_SSBI
+ tristate "Qualcomm Single-wire Serial Bus Interface (SSBI)"
+ depends on I2C&& (ARCH_MSM7X30 || ARCH_MSM8X60)
+ help
+ If you say yes to this option, support will be included for the
+ built-in SSBI interface on Qualcomm MSM family processors.
+
+ Note that SSBI is not an I2C bus, but is functionally related
+ enough such that it is able to leverages the I2C framework.
+
config I2C_STU300
tristate "ST Microelectronics DDC I2C interface"
depends on MACH_U300
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 936880b..79a7ad9 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_I2C_S6000) += i2c-s6000.o
obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o
obj-$(CONFIG_I2C_SH_MOBILE) += i2c-sh_mobile.o
obj-$(CONFIG_I2C_SIMTEC) += i2c-simtec.o
+obj-$(CONFIG_I2C_SSBI) += i2c-ssbi.o
obj-$(CONFIG_I2C_STU300) += i2c-stu300.o
obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o
diff --git a/drivers/i2c/busses/i2c-ssbi.c b/drivers/i2c/busses/i2c-ssbi.c
new file mode 100644
index 0000000..1763ea5
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ssbi.c
@@ -0,0 +1,472 @@
+/* Copyright (c) 2009-2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ */
+/*
+ * SSBI driver for Qualcomm MSM platforms
+ *
+ */
+#include<linux/kernel.h>
+#include<linux/platform_device.h>
+#include<linux/err.h>
+#include<linux/slab.h>
+#include<linux/delay.h>
+#include<linux/io.h>
+#include<linux/i2c.h>
+#include<linux/i2c-ssbi.h>
+
+/* SSBI 2.0 controller registers */
+#define SSBI2_CMD 0x0008
+#define SSBI2_RD 0x0010
+#define SSBI2_STATUS 0x0014
+#define SSBI2_MODE2 0x001C
+
+/* SSBI_CMD fields */
+#define SSBI_CMD_RDWRN (0x01<< 24)
+#define SSBI_CMD_REG_ADDR_SHFT (0x10)
+#define SSBI_CMD_REG_ADDR_MASK (0xFF<< SSBI_CMD_REG_ADDR_SHFT)
+#define SSBI_CMD_REG_DATA_SHFT (0x00)
+#define SSBI_CMD_REG_DATA_MASK (0xFF<< SSBI_CMD_REG_DATA_SHFT)
+
+/* SSBI_STATUS fields */
+#define SSBI_STATUS_DATA_IN 0x10
+#define SSBI_STATUS_RD_CLOBBERED 0x08
+#define SSBI_STATUS_RD_READY 0x04
+#define SSBI_STATUS_READY 0x02
+#define SSBI_STATUS_MCHN_BUSY 0x01
+
+/* SSBI_RD fields */
+#define SSBI_RD_RDWRN 0x01000000
+#define SSBI_RD_REG_ADDR_SHFT 0x10
+#define SSBI_RD_REG_ADDR_MASK (0xFF<< SSBI_RD_REG_ADDR_SHFT)
+#define SSBI_RD_REG_DATA_SHFT (0x00)
+#define SSBI_RD_REG_DATA_MASK (0xFF<< SSBI_RD_REG_DATA_SHFT)
+
+/* SSBI_MODE2 fields */
+#define SSBI_MODE2_REG_ADDR_15_8_SHFT 0x04
+#define SSBI_MODE2_REG_ADDR_15_8_MASK (0x7F<< SSBI_MODE2_REG_ADDR_15_8_SHFT)
+#define SSBI_MODE2_ADDR_WIDTH_SHFT 0x01
+#define SSBI_MODE2_ADDR_WIDTH_MASK (0x07<< SSBI_MODE2_ADDR_WIDTH_SHFT)
+#define SSBI_MODE2_SSBI2_MODE 0x00000001
+
+#define SSBI_MODE2_REG_ADDR_15_8(MD, AD) \
+ (((MD)& 0x0F) | ((((AD)>> 8)<< SSBI_MODE2_REG_ADDR_15_8_SHFT)& \
+ SSBI_MODE2_REG_ADDR_15_8_MASK))
+
+#define SSBI_MODE2_ADDR_WIDTH(N) \
+ ((((N) - 8)<< SSBI_MODE2_ADDR_WIDTH_SHFT)& SSBI_MODE2_ADDR_WIDTH_MASK)
+
+#define SSBI_TIMEOUT_US 100
+
+#define SSBI_CMD_READ(AD) \
+ (SSBI_CMD_RDWRN | (((AD)& 0xFF)<< SSBI_CMD_REG_ADDR_SHFT))
+
+#define SSBI_CMD_WRITE(AD, DT) \
+ ((((AD)& 0xFF)<< SSBI_CMD_REG_ADDR_SHFT) | \
+ (((DT)& 0xFF)<< SSBI_CMD_REG_DATA_SHFT))
+
+/* SSBI PMIC Arbiter command registers */
+#define SSBI_PA_CMD 0x0000
+#define SSBI_PA_RD_STATUS 0x0004
+
+/* SSBI_PA_CMD fields */
+#define SSBI_PA_CMD_RDWRN (0x01<< 24)
+#define SSBI_PA_CMD_REG_ADDR_14_8_SHFT (0x10)
+#define SSBI_PA_CMD_REG_ADDR_14_8_MASK (0x7F<< SSBI_PA_CMD_REG_ADDR_14_8_SHFT)
+#define SSBI_PA_CMD_REG_ADDR_7_0_SHFT (0x08)
+#define SSBI_PA_CMD_REG_ADDR_7_0_MASK (0xFF<< SSBI_PA_CMD_REG_ADDR_7_0_SHFT)
+#define SSBI_PA_CMD_REG_DATA_SHFT (0x00)
+#define SSBI_PA_CMD_REG_DATA_MASK (0xFF<< SSBI_PA_CMD_REG_DATA_SHFT)
+
+#define SSBI_PA_CMD_REG_DATA(DT) \
+ (((DT)<< SSBI_PA_CMD_REG_DATA_SHFT)& SSBI_PA_CMD_REG_DATA_MASK)
+
+#define SSBI_PA_CMD_REG_ADDR(AD) \
+ (((AD)<< SSBI_PA_CMD_REG_ADDR_7_0_SHFT)& \
+ (SSBI_PA_CMD_REG_ADDR_14_8_MASK|SSBI_PA_CMD_REG_ADDR_7_0_MASK))
+
+/* SSBI_PA_RD_STATUS fields */
+#define SSBI_PA_RD_STATUS_TRANS_DONE (0x01<< 27)
+#define SSBI_PA_RD_STATUS_TRANS_DENIED (0x01<< 26)
+#define SSBI_PA_RD_STATUS_REG_DATA_SHFT (0x00)
+#define SSBI_PA_RD_STATUS_REG_DATA_MASK (0xFF<< SSBI_PA_CMD_REG_DATA_SHFT)
+#define SSBI_PA_RD_STATUS_TRANS_COMPLETE \
+ (SSBI_PA_RD_STATUS_TRANS_DONE|SSBI_PA_RD_STATUS_TRANS_DENIED)
+
+#define SSBI_MSM_NAME "i2c_ssbi"
+
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION("2.0");
+MODULE_ALIAS("platform:i2c_ssbi");
+MODULE_AUTHOR("Kenneth Heitke<kheitke@xxxxxxxxxxxxxx>");
+
+struct i2c_ssbi_dev {
+ void __iomem *base;
+ struct device *dev;
+ struct i2c_adapter adapter;
+ unsigned long mem_phys_addr;
+ size_t mem_size;
+ enum msm_ssbi_controller_type controller_type;
+ int (*read)(struct i2c_ssbi_dev *, struct i2c_msg *);
+ int (*write)(struct i2c_ssbi_dev *, struct i2c_msg *);
+};
+
+static inline int
+i2c_ssbi_poll_for_device_ready(struct i2c_ssbi_dev *ssbi)
+{
+ u32 timeout = SSBI_TIMEOUT_US;
+
+ while (!(readl(ssbi->base + SSBI2_STATUS)& SSBI_STATUS_READY)) {
+ if (--timeout == 0) {
+ dev_err(ssbi->dev, "%s: timeout, status %x\n", __func__,
+ readl(ssbi->base + SSBI2_STATUS));
+ return -ETIMEDOUT;
+ }
+ udelay(1);
+ }
+
+ return 0;
+}
+
+static inline int
+i2c_ssbi_poll_for_read_completed(struct i2c_ssbi_dev *ssbi)
+{
+ u32 timeout = SSBI_TIMEOUT_US;
+
+ while (!(readl(ssbi->base + SSBI2_STATUS)& SSBI_STATUS_RD_READY)) {
+ if (--timeout == 0) {
+ dev_err(ssbi->dev, "%s: timeout, status %x\n", __func__,
+ readl(ssbi->base + SSBI2_STATUS));
+ return -ETIMEDOUT;
+ }
+ udelay(1);
+ }
+
+ return 0;
+}
+
+static inline int
+i2c_ssbi_poll_for_transfer_completed(struct i2c_ssbi_dev *ssbi)
+{
+ u32 timeout = SSBI_TIMEOUT_US;
+
+ while ((readl(ssbi->base + SSBI2_STATUS)& SSBI_STATUS_MCHN_BUSY)) {
+ if (--timeout == 0) {
+ dev_err(ssbi->dev, "%s: timeout, status %x\n", __func__,
+ readl(ssbi->base + SSBI2_STATUS));
+ return -ETIMEDOUT;
+ }
+ udelay(1);
+ }
+
+ return 0;
+}
+
+static int
+i2c_ssbi_read_bytes(struct i2c_ssbi_dev *ssbi, struct i2c_msg *msg)
+{
+ int ret = 0;
+ u8 *buf = msg->buf;
+ u16 len = msg->len;
+ u16 addr = msg->addr;
+ u32 read_cmd = SSBI_CMD_READ(addr);
+
+ if (ssbi->controller_type == MSM_SBI_CTRL_SSBI2) {
+ u32 mode2 = readl(ssbi->base + SSBI2_MODE2);
+ writel(SSBI_MODE2_REG_ADDR_15_8(mode2, addr),
+ ssbi->base + SSBI2_MODE2);
+ }
+
+ while (len) {
+ ret = i2c_ssbi_poll_for_device_ready(ssbi);
+ if (ret)
+ goto read_failed;
+
+ writel(read_cmd, ssbi->base + SSBI2_CMD);
+
+ ret = i2c_ssbi_poll_for_read_completed(ssbi);
+ if (ret)
+ goto read_failed;
+
+ *buf++ = readl(ssbi->base + SSBI2_RD)& SSBI_RD_REG_DATA_MASK;
+ len--;
+ }
+
+read_failed:
+ return ret;
+}
+
+static int
+i2c_ssbi_write_bytes(struct i2c_ssbi_dev *ssbi, struct i2c_msg *msg)
+{
+ int ret = 0;
+ u8 *buf = msg->buf;
+ u16 len = msg->len;
+ u16 addr = msg->addr;
+
+ if (ssbi->controller_type == MSM_SBI_CTRL_SSBI2) {
+ u32 mode2 = readl(ssbi->base + SSBI2_MODE2);
+ writel(SSBI_MODE2_REG_ADDR_15_8(mode2, addr),
+ ssbi->base + SSBI2_MODE2);
+ }
+
+ while (len) {
+ ret = i2c_ssbi_poll_for_device_ready(ssbi);
+ if (ret)
+ goto write_failed;
+
+ writel(SSBI_CMD_WRITE(addr, *buf++), ssbi->base + SSBI2_CMD);
+
+ ret = i2c_ssbi_poll_for_transfer_completed(ssbi);
+ if (ret)
+ goto write_failed;
+
+ len--;
+ }
+
+write_failed:
+ return ret;
+}
+
+static inline int
+i2c_ssbi_pa_transfer(struct i2c_ssbi_dev *ssbi, u32 cmd, u8 *data)
+{
+ u32 rd_status;
+ u32 timeout = SSBI_TIMEOUT_US;
+
+ writel(cmd, ssbi->base + SSBI_PA_CMD);
+ rd_status = readl(ssbi->base + SSBI_PA_RD_STATUS);
+
+ while ((rd_status& (SSBI_PA_RD_STATUS_TRANS_COMPLETE)) == 0) {
+
+ if (--timeout == 0) {
+ dev_err(ssbi->dev, "%s: timeout, status %x\n",
+ __func__, rd_status);
+ return -ETIMEDOUT;
+ }
+ udelay(1);
+ rd_status = readl(ssbi->base + SSBI_PA_RD_STATUS);
+ }
+
+ if (rd_status& SSBI_PA_RD_STATUS_TRANS_DENIED) {
+ dev_err(ssbi->dev, "%s: transaction denied, status %x\n",
+ __func__, rd_status);
+ return -EPERM;
+ }
+
+ if (data)
+ *data = (rd_status& SSBI_PA_RD_STATUS_REG_DATA_MASK)>>
+ SSBI_PA_CMD_REG_DATA_SHFT;
+ return 0;
+}
+
+static int
+i2c_ssbi_pa_read_bytes(struct i2c_ssbi_dev *ssbi, struct i2c_msg *msg)
+{
+ int ret = 0;
+ u8 data;
+ u8 *buf = msg->buf;
+ u16 len = msg->len;
+ u32 read_cmd = (SSBI_PA_CMD_RDWRN | SSBI_PA_CMD_REG_ADDR(msg->addr));
+
+ while (len) {
+
+ ret = i2c_ssbi_pa_transfer(ssbi, read_cmd,&data);
+ if (ret)
+ goto read_failed;
+
+ *buf++ = data;
+ len--;
+ }
+
+read_failed:
+ return ret;
+}
+
+static int
+i2c_ssbi_pa_write_bytes(struct i2c_ssbi_dev *ssbi, struct i2c_msg *msg)
+{
+ int ret = 0;
+ u8 *buf = msg->buf;
+ u16 len = msg->len;
+ u32 addr = SSBI_PA_CMD_REG_ADDR(msg->addr);
+
+ while (len) {
+
+ u32 write_cmd = addr | (*buf++& SSBI_PA_CMD_REG_DATA_MASK);
+
+ ret = i2c_ssbi_pa_transfer(ssbi, write_cmd, NULL);
+ if (ret)
+ goto write_failed;
+ len--;
+ }
+
+write_failed:
+ return ret;
+}
+
+static int
+i2c_ssbi_transfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+ int ret = 0;
+ int rem = num;
+ struct i2c_ssbi_dev *ssbi = i2c_get_adapdata(adap);
+
+ while (rem) {
+ if (msgs->flags& I2C_M_RD) {
+ ret = ssbi->read(ssbi, msgs);
+ if (ret)
+ goto transfer_failed;
+ } else {
+ ret = ssbi->write(ssbi, msgs);
+ if (ret)
+ goto transfer_failed;
+ }
+
+ msgs++;
+ rem--;
+ }
+
+ return num;
+
+transfer_failed:
+ return ret;
+}
+
+static u32 i2c_ssbi_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C;
+}
+
+static const struct i2c_algorithm msm_i2c_algo = {
+ .master_xfer = i2c_ssbi_transfer,
+ .functionality = i2c_ssbi_i2c_func,
+};
+
+static int __devinit i2c_ssbi_probe(struct platform_device *pdev)
+{
+ int ret = 0;
+ struct resource *ssbi_res;
+ struct i2c_ssbi_dev *ssbi;
+ struct msm_ssbi_platform_data *pdata;
+
+ pdata = pdev->dev.platform_data;
+ if (!pdata) {
+ ret = -ENXIO;
+ dev_err(&pdev->dev, "platform data not initialized\n");
+ goto err_probe_exit;
+ }
+
+ ssbi = kzalloc(sizeof(struct i2c_ssbi_dev), GFP_KERNEL);
+ if (!ssbi) {
+ ret = -ENOMEM;
+ dev_err(&pdev->dev, "allocation failed\n");
+ goto err_probe_exit;
+ }
+
+ ssbi_res = platform_get_resource_byname(pdev,
+ IORESOURCE_MEM, "ssbi_base");
+ if (!ssbi_res) {
+ ret = -ENXIO;
+ dev_err(&pdev->dev, "get_resource_byname failed\n");
+ goto err_probe_res;
+ }
+
+ ssbi->mem_phys_addr = ssbi_res->start;
+ ssbi->mem_size = resource_size(ssbi_res);
+ if (!request_mem_region(ssbi->mem_phys_addr, ssbi->mem_size,
+ SSBI_MSM_NAME)) {
+ ret = -ENXIO;
+ dev_err(&pdev->dev, "request_mem_region failed\n");
+ goto err_probe_reqmem;
+ }
+
+ ssbi->base = ioremap(ssbi->mem_phys_addr, ssbi->mem_size);
+ if (!ssbi->base) {
+ dev_err(&pdev->dev, "ioremap failed\n");
+ goto err_probe_ioremap;
+ }
+
+ ssbi->dev =&pdev->dev;
+ platform_set_drvdata(pdev, ssbi);
+
+ ssbi->controller_type = pdata->controller_type;
+ if (ssbi->controller_type == MSM_SBI_CTRL_PMIC_ARBITER) {
+ ssbi->read = i2c_ssbi_pa_read_bytes;
+ ssbi->write = i2c_ssbi_pa_write_bytes;
+ } else {
+ ssbi->read = i2c_ssbi_read_bytes;
+ ssbi->write = i2c_ssbi_write_bytes;
+ }
+
+ i2c_set_adapdata(&ssbi->adapter, ssbi);
+ ssbi->adapter.algo =&msm_i2c_algo;
+ strlcpy(ssbi->adapter.name,
+ "MSM SSBI adapter",
+ sizeof(ssbi->adapter.name));
+
+ ssbi->adapter.nr = pdev->id;
+ ret = i2c_add_numbered_adapter(&ssbi->adapter);
+ if (ret) {
+ dev_err(&pdev->dev, "i2c_add_numbered_adapter failed\n");
+ goto err_add_adapter_failed;
+ }
+ return 0;
+
+err_add_adapter_failed:
+ iounmap(ssbi->base);
+ platform_set_drvdata(pdev, NULL);
+err_probe_ioremap:
+ release_mem_region(ssbi->mem_phys_addr, ssbi->mem_size);
+err_probe_reqmem:
+err_probe_res:
+ kfree(ssbi);
+err_probe_exit:
+ return ret;
+}
+
+static int __devexit i2c_ssbi_remove(struct platform_device *pdev)
+{
+ struct i2c_ssbi_dev *ssbi = platform_get_drvdata(pdev);
+
+ platform_set_drvdata(pdev, NULL);
+ i2c_del_adapter(&ssbi->adapter);
+ iounmap(ssbi->base);
+ release_mem_region(ssbi->mem_phys_addr, ssbi->mem_size);
+ kfree(ssbi);
+ return 0;
+}
+
+static struct platform_driver i2c_ssbi_driver = {
+ .probe = i2c_ssbi_probe,
+ .driver = {
+ .name = "i2c_ssbi",
+ .owner = THIS_MODULE,
+ },
+ .remove = __devexit_p(i2c_ssbi_remove),
+};
+
+static int __init i2c_ssbi_init(void)
+{
+ return platform_driver_register(&i2c_ssbi_driver);
+}
+arch_initcall(i2c_ssbi_init);
+
+static void __exit i2c_ssbi_exit(void)
+{
+ platform_driver_unregister(&i2c_ssbi_driver);
+}
+module_exit(i2c_ssbi_exit);
diff --git a/include/linux/i2c-ssbi.h b/include/linux/i2c-ssbi.h
new file mode 100755
index 0000000..75386d5
--- /dev/null
+++ b/include/linux/i2c-ssbi.h
@@ -0,0 +1,33 @@
+/*
+ * Qualcomm MSM i2c Controller Platform Data
+ *
+ * Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+#ifndef __LINUX_I2C_SSBI_H
+#define __LINUX_I2C_SSBI_H
+
+enum msm_ssbi_controller_type {
+ MSM_SBI_CTRL_SSBI = 0,
+ MSM_SBI_CTRL_SSBI2,
+ MSM_SBI_CTRL_PMIC_ARBITER,
+};
+
+struct msm_ssbi_platform_data {
+ enum msm_ssbi_controller_type controller_type;
+};
+
+#endif /* __LINUX_I2C_SSBI_H */
