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Add i2c support to linuxkpi. This is needed by drm-kmod. For every i2c_adapter added by i2c_add_adapter we add a child to the device named "lkpi_iic". This child handle the conversion between Linux i2c_msgs to FreeBSD iic_msgs. For every i2c_adapter added by i2c_bit_add_bus we add a child to the device named "lkpi_iicbb". This child handle the conversion between Linux i2c_msgs to FreeBSD iic_msgs. With the help of iic(4), this expose the i2c controller to userspace allowing a user to query DDC information from a monitor. e.g.: i2c -f /dev/iic0 -a 0x28 -c 128 -d r will query the standard EDID from the monitor if plugged. The bitbang part (lkpi_iicbb) isn't tested at all for now as I don't have compatible hardware (all my hardware have native i2c controller). Tested on: Intel (SandyBridge, Skylake, ApolloLake) Tested on: AMD (Picasso, Polaris (amd64 and arm64)) MFC after: 1 month Reviewed by: hselasky Sponsored by: Beckhoff Automation GmbH & Co. KG Differential Revision: https://reviews.freebsd.org/D33053
152 lines
4 KiB
C
152 lines
4 KiB
C
/*-
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* Copyright (c) 2021 Beckhoff Automation GmbH & Co. KG
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#ifndef _LINUX_I2C_H_
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#define _LINUX_I2C_H_
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#include <sys/types.h>
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#include <sys/errno.h>
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#include <sys/systm.h>
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#include <linux/device.h>
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#define I2C_MAX_ADAPTER_NAME_LENGTH 32
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#define I2C_M_RD 0x0001
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#define I2C_M_NOSTART 0x0002
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#define I2C_M_STOP 0x0004
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/* No need for us */
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#define I2C_FUNC_I2C 0
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#define I2C_FUNC_SMBUS_EMUL 0
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#define I2C_FUNC_SMBUS_READ_BLOCK_DATA 0
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#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0
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#define I2C_FUNC_10BIT_ADDR 0
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#define I2C_CLASS_DDC 0x8
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#define I2C_CLASS_SPD 0x80
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struct i2c_adapter {
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struct module *owner;
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unsigned int class;
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char name[I2C_MAX_ADAPTER_NAME_LENGTH];
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struct device dev;
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const struct i2c_lock_operations *lock_ops;
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const struct i2c_algorithm *algo;
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void *algo_data;
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int retries;
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void *data;
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};
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struct i2c_msg {
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uint16_t addr;
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uint16_t flags;
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uint16_t len;
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uint8_t *buf;
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};
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struct i2c_algorithm {
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int (*master_xfer)(struct i2c_adapter *, struct i2c_msg *, int);
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uint32_t (*functionality)(struct i2c_adapter *);
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};
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struct i2c_lock_operations {
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void (*lock_bus)(struct i2c_adapter *, unsigned int);
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int (*trylock_bus)(struct i2c_adapter *, unsigned int);
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void (*unlock_bus)(struct i2c_adapter *, unsigned int);
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};
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int lkpi_i2c_add_adapter(struct i2c_adapter *adapter);
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int lkpi_i2c_del_adapter(struct i2c_adapter *adapter);
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int lkpi_i2cbb_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int nmsgs);
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#define i2c_add_adapter(adapter) lkpi_i2c_add_adapter(adapter)
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#define i2c_del_adapter(adapter) lkpi_i2c_del_adapter(adapter)
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#define i2c_get_adapter(x) NULL
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#define i2c_put_adapter(x)
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static inline int
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do_i2c_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int nmsgs)
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{
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int ret, retries;
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retries = adapter->retries == 0 ? 1 : adapter->retries;
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for (; retries != 0; retries--) {
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if (adapter->algo->master_xfer != NULL)
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ret = adapter->algo->master_xfer(adapter, msgs, nmsgs);
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else
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ret = lkpi_i2cbb_transfer(adapter, msgs, nmsgs);
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if (ret != -EAGAIN)
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break;
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}
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return (ret);
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}
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static inline int
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i2c_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int nmsgs)
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{
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int ret;
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if (!adapter->algo)
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return (-EOPNOTSUPP);
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if (adapter->lock_ops)
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adapter->lock_ops->lock_bus(adapter, 0);
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ret = do_i2c_transfer(adapter, msgs, nmsgs);
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if (adapter->lock_ops)
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adapter->lock_ops->unlock_bus(adapter, 0);
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return (ret);
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}
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/* Unlocked version of i2c_transfer */
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static inline int
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__i2c_transfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int nmsgs)
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{
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return (do_i2c_transfer(adapter, msgs, nmsgs));
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}
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static inline void
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i2c_set_adapdata(struct i2c_adapter *adapter, void *data)
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{
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adapter->data = data;
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}
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static inline void *
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i2c_get_adapdata(struct i2c_adapter *adapter)
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{
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return (adapter->data);
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}
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#endif /* _LINUX_I2C_H_ */
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