439cee9098
If one wants to implement both i2c_bus.h and i2c_simple.h APIs the compilation unit needs to be guarded or coordinated carefully with different compilation units. Instead, name the i2c_bus functions with _dev such that it indicates that they operate on struct device. One other change to allow i2c_bus.h to be built in non-ramstage environments is to ensure DEVTREE_CONST is used for the dev field in struct bus. BUG=b:72121803 Change-Id: I267e27e62c95013e8ff8b0728dbe9e7b523de453 Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/23370 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Martin Roth <martinroth@google.com> Reviewed-by: Furquan Shaikh <furquan@google.com>
92 lines
2.6 KiB
C
92 lines
2.6 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef _DEVICE_I2C_BUS_H_
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#define _DEVICE_I2C_BUS_H_
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#include <stdlib.h>
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#include <stdint.h>
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#include <device/i2c.h>
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#include <device/device.h>
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/* I2C bus operation for ramstage drivers */
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struct i2c_bus_operations {
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int (*transfer)(struct device *, const struct i2c_msg *, size_t count);
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};
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/*
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* Returns the first upstream facing link whose bus implements either
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* `i2c_bus_operations` *or* `smbus_bus_operations`.
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*
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* If not NULL, guarantees that `->dev`, `->dev->ops` and either
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* `->dev->ops->ops_i2c_bus` or `->dev->ops->ops_smbus_bus` are
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* not NULL.
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*/
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struct bus *i2c_link(struct device *);
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/*
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* Shorthand for `i2c_link(dev)->dev`.
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*
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* Returns NULL if i2c_link(dev) returns NULL.
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*/
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static inline DEVTREE_CONST struct device *i2c_busdev(struct device *dev)
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{
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struct bus *const link = i2c_link(dev);
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return link ? link->dev : NULL;
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}
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/*
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* Slave driver interface functions. These will look for the next
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* `i2c_bus_operations` *or* `smbus_bus_operations` and perform the
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* respective transfers.
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*
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* The interface is limited to what current slave drivers demand.
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* Extend as required.
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*
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* All functions return a negative `enum cb_err` value on error.
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* Either CB_ERR, CB_ERR_ARG or any CB_I2C_* (cf. include/types.h).
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*/
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/*
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* Reads one byte.
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* Compatible to smbus_recv_byte().
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*
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* Returns the read byte on success, negative `enum cb_err` value on error.
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*/
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int i2c_dev_readb(struct device *);
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/*
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* Writes the byte `val`.
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* Compatible to smbus_send_byte().
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*
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* Returns 0 on success, negative `enum cb_err` value on error.
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*/
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int i2c_dev_writeb(struct device *, uint8_t val);
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/*
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* Sends the register offset `off` and reads one byte.
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* Compatible to smbus_read_byte().
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*
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* Returns the read byte on success, negative `enum cb_err` value on error.
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*/
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int i2c_dev_readb_at(struct device *, uint8_t off);
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/*
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* Sends the register offset `off` followed by the byte `val`.
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* Compatible to smbus_write_byte().
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*
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* Returns 0 on success, negative `enum cb_err` value on error.
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*/
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int i2c_dev_writeb_at(struct device *, uint8_t off, uint8_t val);
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#endif /* _DEVICE_I2C_BUS_H_ */
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