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![Octavian Purdila](/assets/img/avatar_default.png)
This patch implements the USB part of the Diolan USB-I2C/SPI/GPIO Master Adapter DLN-2. Details about the device can be found here: https://www.diolan.com/i2c/i2c_interface.html. Information about the USB protocol can be found in the Programmer's Reference Manual [1], see section 1.7. Because the hardware has a single transmit endpoint and a single receive endpoint the communication between the various DLN2 drivers and the hardware will be muxed/demuxed by this driver. Each DLN2 module will be identified by the handle field within the DLN2 message header. If a DLN2 module issues multiple commands in parallel they will be identified by the echo counter field in the message header. The DLN2 modules can use the dln2_transfer() function to issue a command and wait for its response. They can also register a callback that is going to be called when a specific event id is generated by the device (e.g. GPIO interrupts). The device uses handle 0 for sending events. [1] https://www.diolan.com/downloads/dln-api-manual.pdf Signed-off-by: Octavian Purdila <octavian.purdila@intel.com> Reviewed-by: Johan Hovold <johan@kernel.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
103 lines
3.5 KiB
C
103 lines
3.5 KiB
C
#ifndef __LINUX_USB_DLN2_H
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#define __LINUX_USB_DLN2_H
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#define DLN2_CMD(cmd, id) ((cmd) | ((id) << 8))
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struct dln2_platform_data {
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u16 handle; /* sub-driver handle (internally used only) */
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u8 port; /* I2C/SPI port */
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};
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/**
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* dln2_event_cb_t - event callback function signature
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*
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* @pdev - the sub-device that registered this callback
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* @echo - the echo header field received in the message
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* @data - the data payload
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* @len - the data payload length
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*
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* The callback function is called in interrupt context and the data payload is
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* only valid during the call. If the user needs later access of the data, it
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* must copy it.
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*/
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typedef void (*dln2_event_cb_t)(struct platform_device *pdev, u16 echo,
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const void *data, int len);
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/**
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* dl2n_register_event_cb - register a callback function for an event
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*
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* @pdev - the sub-device that registers the callback
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* @event - the event for which to register a callback
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* @event_cb - the callback function
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*
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* @return 0 in case of success, negative value in case of error
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*/
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int dln2_register_event_cb(struct platform_device *pdev, u16 event,
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dln2_event_cb_t event_cb);
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/**
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* dln2_unregister_event_cb - unregister the callback function for an event
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*
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* @pdev - the sub-device that registered the callback
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* @event - the event for which to register a callback
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*/
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void dln2_unregister_event_cb(struct platform_device *pdev, u16 event);
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/**
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* dln2_transfer - issue a DLN2 command and wait for a response and the
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* associated data
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*
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* @pdev - the sub-device which is issuing this transfer
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* @cmd - the command to be sent to the device
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* @obuf - the buffer to be sent to the device; it can be NULL if the user
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* doesn't need to transmit data with this command
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* @obuf_len - the size of the buffer to be sent to the device
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* @ibuf - any data associated with the response will be copied here; it can be
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* NULL if the user doesn't need the response data
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* @ibuf_len - must be initialized to the input buffer size; it will be modified
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* to indicate the actual data transferred;
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*
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* @return 0 for success, negative value for errors
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*/
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int dln2_transfer(struct platform_device *pdev, u16 cmd,
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const void *obuf, unsigned obuf_len,
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void *ibuf, unsigned *ibuf_len);
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/**
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* dln2_transfer_rx - variant of @dln2_transfer() where TX buffer is not needed
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*
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* @pdev - the sub-device which is issuing this transfer
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* @cmd - the command to be sent to the device
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* @ibuf - any data associated with the response will be copied here; it can be
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* NULL if the user doesn't need the response data
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* @ibuf_len - must be initialized to the input buffer size; it will be modified
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* to indicate the actual data transferred;
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*
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* @return 0 for success, negative value for errors
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*/
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static inline int dln2_transfer_rx(struct platform_device *pdev, u16 cmd,
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void *ibuf, unsigned *ibuf_len)
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{
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return dln2_transfer(pdev, cmd, NULL, 0, ibuf, ibuf_len);
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}
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/**
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* dln2_transfer_tx - variant of @dln2_transfer() where RX buffer is not needed
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*
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* @pdev - the sub-device which is issuing this transfer
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* @cmd - the command to be sent to the device
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* @obuf - the buffer to be sent to the device; it can be NULL if the
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* user doesn't need to transmit data with this command
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* @obuf_len - the size of the buffer to be sent to the device
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*
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* @return 0 for success, negative value for errors
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*/
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static inline int dln2_transfer_tx(struct platform_device *pdev, u16 cmd,
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const void *obuf, unsigned obuf_len)
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{
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return dln2_transfer(pdev, cmd, obuf, obuf_len, NULL, NULL);
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}
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#endif
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