Adds support for USB-I2C interface of Cypress Semiconductor CYUSBS234 USB-Serial Bridge controller. The read/write operation is setup using vendor command through control endpoint and actual data transfer happens through bulk in/out endpoints. Details about the device can be found at: http://www.cypress.com/?rID=84126 Signed-off-by: Muthu Mani <muth@xxxxxxxxxxx> Signed-off-by: Rajaram Regupathy <rera@xxxxxxxxxxx> --- Changes since v2: * Retrieved the i2c transfer status using interrupt in endpoint * Used kstrtol instead of manually parsing and scnprintf instead of sprintf * Given i2c adapter device for dev_xxx * cleaned up the code Changes since v1: * allocated memory on heap for usb transfer data * Used DEVICE_ATTR_xx and friends and attribute groups * Added the device files under i2c-adapter rather than platform device drivers/i2c/busses/Kconfig | 12 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-cyusbs23x.c | 584 +++++++++++++++++++++++++++++++++++++ 3 files changed, 597 insertions(+) create mode 100644 drivers/i2c/busses/i2c-cyusbs23x.c diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 2ac87fa..1fdc6ec 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -848,6 +848,18 @@ config I2C_RCAR comment "External I2C/SMBus adapter drivers" +config I2C_CYUSBS23X + tristate "CYUSBS23x I2C adapter" + depends on MFD_CYUSBS23X && USB + help + Say yes if you would like to access Cypress CYUSBS23x I2C device. + + This driver enables the I2C interface of CYUSBS23x USB Serial Bridge + controller. + + This driver can also be built as a module. If so, the module will be + called i2c-cyusbs23x. + config I2C_DIOLAN_U2C tristate "Diolan U2C-12 USB adapter" depends on USB diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 49bf07e..cbf28cb 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -84,6 +84,7 @@ obj-$(CONFIG_I2C_XLR) += i2c-xlr.o obj-$(CONFIG_I2C_RCAR) += i2c-rcar.o # External I2C/SMBus adapter drivers +obj-$(CONFIG_I2C_CYUSBS23X) += i2c-cyusbs23x.o obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o obj-$(CONFIG_I2C_PARPORT_LIGHT) += i2c-parport-light.o diff --git a/drivers/i2c/busses/i2c-cyusbs23x.c b/drivers/i2c/busses/i2c-cyusbs23x.c new file mode 100644 index 0000000..16d3995 --- /dev/null +++ b/drivers/i2c/busses/i2c-cyusbs23x.c @@ -0,0 +1,584 @@ +/* + * I2C subdriver for Cypress CYUSBS234 USB-Serial Bridge controller. + * Details about the device can be found at: + * http://www.cypress.com/?rID=84126 + * + * Copyright (c) 2014 Cypress Semiconductor Corporation. + * + * Author: + * Rajaram Regupathy <rera@xxxxxxxxxxx> + * + * Additional contributors include: + * Muthu Mani <muth@xxxxxxxxxxx> + * + * 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. + */ + +/* + * It exposes sysfs entries under the i2c adapter for getting the i2c transfer + * status, reset i2c read/write module, get/set nak and stop bits. + */ + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> + +#include <linux/usb.h> +#include <linux/i2c.h> + +#include <linux/mfd/cyusbs23x.h> + +enum cy_i2c_io_mode { + CY_I2C_MODE_READ = 0, + CY_I2C_MODE_WRITE = 1 +}; + +#define CY_I2C_XFER_STATUS_LEN 3 + +struct cyusbs_i2c_config { + /* Frequency of operation. Only valid values are 100KHz and 400KHz */ + u32 frequency; + u8 slave_addr; /* Slave address to be used when in slave mode */ + u8 is_msb_first; /* Whether to transmit MSB first */ + /* + * Whether block is configured as a master: + * 1 - The block functions as I2C master; + * 0 - The block functions as I2C slave + */ + u8 is_master; + u8 s_ignore; /* Ignore general call in slave mode */ + /* Whether to stretch clock in case of no FIFO availability */ + u8 clock_stretch; + /* Whether to loop back TX data to RX. Valid only for debug purposes */ + u8 is_loopback; + u8 reserved[6]; /* Reserved for future use */ +} __packed; + +struct cyusbs_i2c { + struct i2c_adapter i2c_adapter; + struct cyusbs_i2c_config *i2c_config; + struct mutex lock; + + bool is_stop_bit; /* set the stop bit for i2c transfer */ + bool is_nak_bit; /* set the nak bit for i2c transfer */ +}; + +#define to_cyusbs_i2c(a) container_of(a, struct cyusbs_i2c, i2c_adapter) + +static int cy_i2c_get_status(struct i2c_adapter *adapter, u8 *buf, u16 mode); +static int cy_i2c_reset(struct i2c_adapter *adapter, u16 mode); + +static ssize_t i2c_read_status_show(struct device *d, + struct device_attribute *attr, char *buf) +{ + struct i2c_adapter *adapter = to_i2c_adapter(d); + + /* Updates buffer with 3 bytes status (hex data) */ + return cy_i2c_get_status(adapter, buf, CY_I2C_MODE_READ); +} + +static ssize_t i2c_write_status_show(struct device *d, + struct device_attribute *attr, char *buf) +{ + struct i2c_adapter *adapter = to_i2c_adapter(d); + + /* Updates buffer with 3 bytes status (hex data) */ + return cy_i2c_get_status(adapter, buf, CY_I2C_MODE_WRITE); +} + +static ssize_t i2c_read_reset_store(struct device *d, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int ret; + long value; + struct i2c_adapter *adapter = to_i2c_adapter(d); + + ret = kstrtol(buf, 0, &value); + if (ret) + return ret; + + if (value != 1) + return -EINVAL; + + ret = cy_i2c_reset(adapter, CY_I2C_MODE_READ); + if (!ret) + ret = count; + + return ret; +} + +static ssize_t i2c_write_reset_store(struct device *d, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int ret; + long value; + struct i2c_adapter *adapter = to_i2c_adapter(d); + + ret = kstrtol(buf, 0, &value); + if (ret) + return ret; + + if (value != 1) + return -EINVAL; + + ret = cy_i2c_reset(adapter, CY_I2C_MODE_WRITE); + if (!ret) + ret = count; + + return ret; +} + +static ssize_t is_stop_bit_show(struct device *d, + struct device_attribute *attr, char *buf) +{ + struct i2c_adapter *adapter = to_i2c_adapter(d); + struct cyusbs_i2c *cy_i2c = to_cyusbs_i2c(adapter); + + return scnprintf(buf, 3, "%d\n", cy_i2c->is_stop_bit); +} + +static ssize_t is_stop_bit_store(struct device *d, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct i2c_adapter *adapter = to_i2c_adapter(d); + struct cyusbs_i2c *cy_i2c = to_cyusbs_i2c(adapter); + long value; + int ret; + + ret = kstrtol(buf, 0, &value); + if (ret) + return ret; + + if (value != 0 && value != 1) + return -EINVAL; + + cy_i2c->is_stop_bit = (bool)value; + + return count; +} + +static ssize_t is_nak_bit_show(struct device *d, + struct device_attribute *attr, char *buf) +{ + struct i2c_adapter *adapter = to_i2c_adapter(d); + struct cyusbs_i2c *cy_i2c = to_cyusbs_i2c(adapter); + + return scnprintf(buf, 3, "%d\n", cy_i2c->is_nak_bit); +} + +static ssize_t is_nak_bit_store(struct device *d, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct i2c_adapter *adapter = to_i2c_adapter(d); + struct cyusbs_i2c *cy_i2c = to_cyusbs_i2c(adapter); + long value; + int ret; + + ret = kstrtol(buf, 0, &value); + if (ret) + return ret; + + if (value != 0 && value != 1) + return -EINVAL; + + cy_i2c->is_nak_bit = (bool)value; + + return count; +} + +static DEVICE_ATTR_RO(i2c_read_status); +static DEVICE_ATTR_RO(i2c_write_status); +static DEVICE_ATTR_WO(i2c_read_reset); +static DEVICE_ATTR_WO(i2c_write_reset); +static DEVICE_ATTR_RW(is_stop_bit); +static DEVICE_ATTR_RW(is_nak_bit); + +static struct attribute *cyusbs_i2c_device_attrs[] = { + &dev_attr_i2c_read_status.attr, + &dev_attr_i2c_write_status.attr, + &dev_attr_i2c_read_reset.attr, + &dev_attr_i2c_write_reset.attr, + &dev_attr_is_stop_bit.attr, + &dev_attr_is_nak_bit.attr, + NULL +}; + +ATTRIBUTE_GROUPS(cyusbs_i2c_device); + +static int cy_i2c_get_status(struct i2c_adapter *adapter, u8 *buf, u16 mode) +{ + int ret; + u16 wIndex, wValue, scb_index; + u8 *data; + struct cyusbs23x *cyusbs = (struct cyusbs23x *)adapter->algo_data; + struct cyusbs_i2c *cy_i2c = to_cyusbs_i2c(adapter); + + scb_index = cyusbs->intf_num & 0x01; + wValue = ((scb_index << CY_SCB_INDEX_SHIFT) | mode); + wIndex = 0; + data = kmalloc(CY_I2C_XFER_STATUS_LEN, GFP_KERNEL); + if (data == NULL) + return -ENOMEM; + + mutex_lock(&cy_i2c->lock); + /* read the i2c transfer status */ + ret = usb_control_msg(cyusbs->usb_dev, + usb_rcvctrlpipe(cyusbs->usb_dev, 0), + CY_I2C_GET_STATUS_CMD, + USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, + wValue, wIndex, data, CY_I2C_XFER_STATUS_LEN, + CY_USBS_CTRL_XFER_TIMEOUT); + mutex_unlock(&cy_i2c->lock); + if (ret != CY_I2C_XFER_STATUS_LEN) { + dev_err(&adapter->dev, "%s: failed to get status: %d", + __func__, ret); + ret = usb_translate_errors(ret); + goto status_error; + } + + memcpy(buf, data, CY_I2C_XFER_STATUS_LEN); + buf[CY_I2C_XFER_STATUS_LEN] = 0; + + dev_dbg(&adapter->dev, "%s: %02x %02x %02x\n", __func__, + buf[0], buf[1], buf[2]); + +status_error: + kfree(data); + return ret; +} + +static int cy_i2c_reset(struct i2c_adapter *adapter, u16 mode) +{ + int ret; + u16 wIndex, wValue, scb_index; + struct cyusbs23x *cyusbs = (struct cyusbs23x *)adapter->algo_data; + struct cyusbs_i2c *cy_i2c = to_cyusbs_i2c(adapter); + + scb_index = cyusbs->intf_num & 0x01; + wValue = ((scb_index << CY_SCB_INDEX_SHIFT) | mode); + wIndex = 0; + + mutex_lock(&cy_i2c->lock); + ret = usb_control_msg(cyusbs->usb_dev, + usb_sndctrlpipe(cyusbs->usb_dev, 0), + CY_I2C_RESET_CMD, + USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, + wValue, wIndex, NULL, 0, CY_USBS_CTRL_XFER_TIMEOUT); + mutex_unlock(&cy_i2c->lock); + if (ret) { + dev_err(&adapter->dev, "%s: failed to reset: %d", + __func__, ret); + ret = usb_translate_errors(ret); + } + + return ret; +} + +static int cy_i2c_recv_status(struct i2c_adapter *adapter) +{ + int ret, actual_len; + u8 *data; + struct cyusbs23x *cyusbs = (struct cyusbs23x *)adapter->algo_data; + + data = kmalloc(CY_I2C_XFER_STATUS_LEN, GFP_KERNEL); + if (data == NULL) + return -ENOMEM; + + /* read the i2c transfer status */ + ret = usb_interrupt_msg(cyusbs->usb_dev, + usb_rcvintpipe(cyusbs->usb_dev, cyusbs->intr_in_ep_num), + data, CY_I2C_XFER_STATUS_LEN, &actual_len, + CY_USBS_INTR_XFER_TIMEOUT); + if (ret < 0) { + dev_err(&adapter->dev, + "Failed to read from interrupt ep: %d\n", ret); + ret = usb_translate_errors(ret); + goto intr_ep_error; + } + + dev_dbg(&adapter->dev, "%s: %02x %02x %02x\n", __func__, + data[0], data[1], data[2]); + + if (data[0] & 0x1) + ret = -ETIMEDOUT; + +intr_ep_error: + kfree(data); + return ret; +} + +static int cy_get_i2c_config(struct cyusbs23x *cyusbs, + struct cyusbs_i2c *cy_i2c) +{ + int ret; + u16 scb_index; + + scb_index = (cyusbs->intf_num & 0x01) << CY_SCB_INDEX_SHIFT; + + ret = usb_control_msg(cyusbs->usb_dev, + usb_rcvctrlpipe(cyusbs->usb_dev, 0), + CY_I2C_GET_CONFIG_CMD, + USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, + scb_index, 0, cy_i2c->i2c_config, + sizeof(*cy_i2c->i2c_config), CY_USBS_CTRL_XFER_TIMEOUT); + if (ret != sizeof(*cy_i2c->i2c_config)) { + dev_err(&cyusbs->usb_intf->dev, "%s: %d\n", + __func__, ret); + ret = usb_translate_errors(ret); + goto config_error; + } + + dev_dbg(&cyusbs->usb_intf->dev, + "%s: freq=%d, slave_addr=0x%02x, msb_first=%d, master=%d, ignore=%d, clock_stretch=%d, loopback=%d\n", + __func__, cy_i2c->i2c_config->frequency, + cy_i2c->i2c_config->slave_addr, + cy_i2c->i2c_config->is_msb_first, + cy_i2c->i2c_config->is_master, + cy_i2c->i2c_config->s_ignore, + cy_i2c->i2c_config->clock_stretch, + cy_i2c->i2c_config->is_loopback); + +config_error: + return ret; +} + +static int cy_i2c_set_data_config(struct cyusbs23x *cyusbs, + struct cyusbs_i2c *cy_i2c, u16 slave_addr, + u16 length, u8 command) +{ + int ret; + u16 wIndex, wValue, scb_index; + + scb_index = (cyusbs->intf_num & 0x01) << CY_SCB_INDEX_SHIFT; + slave_addr = (slave_addr & 0x7F); + wValue = scb_index | cy_i2c->is_stop_bit | cy_i2c->is_nak_bit << 1; + wValue |= (slave_addr << 8); + wIndex = length; + + dev_dbg(&cy_i2c->i2c_adapter.dev, + "%s, cmd=0x%x, val=0x%x, idx=0x%x\n", + __func__, command, wValue, wIndex); + + ret = usb_control_msg(cyusbs->usb_dev, + usb_sndctrlpipe(cyusbs->usb_dev, 0), + command, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, + wValue, wIndex, NULL, 0, CY_USBS_CTRL_XFER_TIMEOUT); + + return ret; +} + +static int cy_i2c_read(struct i2c_adapter *adapter, struct i2c_msg *msgs) +{ + int ret; + int actual_read_len = 0; + struct cyusbs23x *cyusbs = (struct cyusbs23x *)adapter->algo_data; + + dev_dbg(&adapter->dev, "%s\n", __func__); + + ret = usb_bulk_msg(cyusbs->usb_dev, + usb_rcvbulkpipe(cyusbs->usb_dev, cyusbs->bulk_in_ep_num), + msgs[0].buf, + msgs[0].len, + &actual_read_len, CY_USBS_BULK_XFER_TIMEOUT); + if (ret) + dev_err(&adapter->dev, + "read %d/%d returned %d\n", + actual_read_len, msgs[0].len, ret); + + ret = cy_i2c_recv_status(adapter); + + return ret; +} + +static int cy_i2c_write(struct i2c_adapter *adapter, struct i2c_msg *msgs) +{ + int ret; + int actual_write_len = 0; + struct cyusbs23x *cyusbs = (struct cyusbs23x *)adapter->algo_data; + + dev_dbg(&adapter->dev, "%s\n", __func__); + + ret = usb_bulk_msg(cyusbs->usb_dev, + usb_sndbulkpipe(cyusbs->usb_dev, cyusbs->bulk_out_ep_num), + msgs[0].buf, + msgs[0].len, + &actual_write_len, CY_USBS_BULK_XFER_TIMEOUT); + if (ret) + dev_err(&adapter->dev, + "write %d/%d returned %d\n", + actual_write_len, msgs[0].len, ret); + + ret = cy_i2c_recv_status(adapter); + + return ret; +} + +static int cy_i2c_xfer(struct i2c_adapter *adapter, + struct i2c_msg *msgs, int num) +{ + int ret = 0; + struct cyusbs_i2c *cy_i2c; + struct cyusbs23x *cyusbs = (struct cyusbs23x *)adapter->algo_data; + + dev_dbg(&adapter->dev, "%s\n", __func__); + + if (num > 1) { + dev_err(&adapter->dev, "i2c_msg number is > 1\n"); + return -EIO; + } + + cy_i2c = to_cyusbs_i2c(adapter); + + mutex_lock(&cy_i2c->lock); + if (msgs[0].flags & I2C_M_RD) { + dev_dbg(&adapter->dev, + "I2C read requested for addr 0x%02x, data length %d\n", + msgs[0].addr, msgs[0].len); + + ret = cy_i2c_set_data_config(cyusbs, cy_i2c, msgs[0].addr, + msgs[0].len, CY_I2C_READ_CMD); + if (ret < 0) { + dev_err(&adapter->dev, + "Set Config (read) failed with %d\n", ret); + goto io_error; + } + + ret = cy_i2c_read(adapter, msgs); + if (ret) { + dev_err(&adapter->dev, + "Read failed with error code %d\n", ret); + goto io_error; + } + } else { + dev_dbg(&adapter->dev, + "I2C write requested for addr 0x%02x, data length %d\n", + msgs[0].addr, msgs[0].len); + + ret = cy_i2c_set_data_config(cyusbs, cy_i2c, msgs[0].addr, + msgs[0].len, CY_I2C_WRITE_CMD); + if (ret < 0) { + dev_err(&adapter->dev, + "Set Config (write) failed with %d\n", ret); + goto io_error; + } + + ret = cy_i2c_write(adapter, msgs); + if (ret) { + dev_err(&adapter->dev, + "Write failed with error code %d\n", ret); + goto io_error; + } + } + mutex_unlock(&cy_i2c->lock); + return ret; + +io_error: + mutex_unlock(&cy_i2c->lock); + return ret; +} + +static u32 cy_i2c_func(struct i2c_adapter *adapter) +{ + return I2C_FUNC_I2C; +} + +static const struct i2c_algorithm i2c_cyusbs23x_algorithm = { + .master_xfer = cy_i2c_xfer, + .functionality = cy_i2c_func, +}; + +static int cyusbs23x_i2c_probe(struct platform_device *pdev) +{ + struct cyusbs23x *cyusbs; + struct cyusbs_i2c *cy_i2c; + int ret = 0; + + dev_dbg(&pdev->dev, "%s\n", __func__); + + cyusbs = dev_get_drvdata(pdev->dev.parent); + + cy_i2c = devm_kzalloc(&pdev->dev, sizeof(*cy_i2c), GFP_KERNEL); + if (cy_i2c == NULL) + return -ENOMEM; + + cy_i2c->i2c_config = devm_kzalloc(&pdev->dev, + sizeof(struct cyusbs_i2c_config), + GFP_KERNEL); + if (cy_i2c->i2c_config == NULL) + return -ENOMEM; + + mutex_init(&cy_i2c->lock); + cy_i2c->is_stop_bit = 1; + cy_i2c->is_nak_bit = 1; + + cy_i2c->i2c_adapter.owner = THIS_MODULE; + cy_i2c->i2c_adapter.class = I2C_CLASS_HWMON; + cy_i2c->i2c_adapter.algo = &i2c_cyusbs23x_algorithm; + cy_i2c->i2c_adapter.algo_data = cyusbs; + snprintf(cy_i2c->i2c_adapter.name, sizeof(cy_i2c->i2c_adapter.name), + "cyusbs23x_i2c at bus %03d dev %03d intf %03d", + cyusbs->usb_dev->bus->busnum, cyusbs->usb_dev->devnum, + cyusbs->intf_num); + cy_i2c->i2c_adapter.dev.parent = &pdev->dev; + cy_i2c->i2c_adapter.dev.groups = cyusbs_i2c_device_groups; + + ret = cy_get_i2c_config(cyusbs, cy_i2c); + if (ret < 0) { + dev_err(&pdev->dev, "error to get i2c config\n"); + goto error; + } + + if (!cy_i2c->i2c_config->is_master) { + ret = -ENODEV; + dev_err(&pdev->dev, "not an I2C master\n"); + goto error; + } + + ret = i2c_add_adapter(&cy_i2c->i2c_adapter); + if (ret != 0) { + dev_err(&pdev->dev, "failed to add i2c adapter\n"); + goto error; + } + + platform_set_drvdata(pdev, cy_i2c); + + dev_dbg(&pdev->dev, "added I2C adapter\n"); + return 0; + +error: + dev_err(&pdev->dev, "error occured %d\n", ret); + return ret; +} + +static int cyusbs23x_i2c_remove(struct platform_device *pdev) +{ + struct cyusbs_i2c *cy_i2c = platform_get_drvdata(pdev); + + dev_dbg(&pdev->dev, "%s\n", __func__); + i2c_del_adapter(&cy_i2c->i2c_adapter); + return 0; +} + +static struct platform_driver cyusbs23x_i2c_driver = { + .driver.name = "cyusbs23x-i2c", + .probe = cyusbs23x_i2c_probe, + .remove = cyusbs23x_i2c_remove, +}; + +module_platform_driver(cyusbs23x_i2c_driver); + +MODULE_AUTHOR("Rajaram Regupathy <rera@xxxxxxxxxxx>"); +MODULE_AUTHOR("Muthu Mani <muth@xxxxxxxxxxx>"); +MODULE_DESCRIPTION("I2C adapter driver for CYUSBS23x"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:cyusbs23x-i2c"); -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
