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SubjectRe: [PATCH v5 2/3] i2c: add support for Cypress CYUSBS234 USB-I2C adapter

On Saturday 13 December 2014 05:17 PM, Muthu Mani wrote:
> 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@cypress.com>
> Signed-off-by: Rajaram Regupathy <rera@cypress.com>
> ---
> Changes since v4:
> * used interface number from interface pointer instead of separate member var
>
> Changes since v3:
> * corrected typo
>
> 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 | 585 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 598 insertions(+)
> create mode 100644 drivers/i2c/busses/i2c-cyusbs23x.c
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index b4d135c..a9cd3e2 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -871,6 +871,18 @@ config I2C_RCAR
>
> comment "External I2C/SMBus adapter drivers"
>
> +config I2C_CYUSBS23X
> + tristate "CYUSBS23x I2C adapter"
> + depends on MFD_CYUSBS23X
> + 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 cdac7f1..ad2b283 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -86,6 +86,7 @@ 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-$(CONFIG_I2C_DLN2) += i2c-dln2.o
> obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o
> diff --git a/drivers/i2c/busses/i2c-cyusbs23x.c b/drivers/i2c/busses/i2c-cyusbs23x.c
> new file mode 100644
> index 0000000..452c370
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-cyusbs23x.c
> @@ -0,0 +1,585 @@
> +/*
> + * 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@cypress.com>
> + *
> + * Additional contributors include:
> + * Muthu Mani <muth@cypress.com>
> + *
> + * 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>
> +
> +#define CY_I2C_MODE_READ 0
> +#define 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);
> + u8 ifnum = cyusbs->usb_intf->cur_altsetting->desc.bInterfaceNumber;
> +
> + scb_index = ifnum & 0x01;
> + wValue = ((scb_index << CY_SCB_INDEX_SHIFT) | mode);
> + wIndex = 0;

One line space..

> + data = kmalloc(CY_I2C_XFER_STATUS_LEN, GFP_KERNEL);
> + if (data == NULL)
> + return -ENOMEM;
> +

if(!data)
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);
> + u8 ifnum = cyusbs->usb_intf->cur_altsetting->desc.bInterfaceNumber;
> +
> + scb_index = ifnum & 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;
> +

if(!data)
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;
> + u8 ifnum = cyusbs->usb_intf->cur_altsetting->desc.bInterfaceNumber;
> +
> + scb_index = (ifnum & 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;
> + u8 ifnum = cyusbs->usb_intf->cur_altsetting->desc.bInterfaceNumber;
> +
> + scb_index = (ifnum & 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;
> +

dto...

> + cy_i2c->i2c_config = devm_kzalloc(&pdev->dev,
> + sizeof(struct cyusbs_i2c_config),
> + GFP_KERNEL);
> + if (cy_i2c->i2c_config == NULL)
> + return -ENOMEM;
> +

dto...

--
Thanks and Regards,
Varka Bhadram.



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