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347 lines
8.4 KiB
347 lines
8.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* drivers/i2c/busses/i2c-tegra-bpmp.c |
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* |
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* Copyright (c) 2016 NVIDIA Corporation. All rights reserved. |
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* |
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* Author: Shardar Shariff Md <[email protected]> |
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*/ |
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#include <linux/err.h> |
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#include <linux/i2c.h> |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/of_device.h> |
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#include <linux/platform_device.h> |
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#include <linux/pm_runtime.h> |
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#include <soc/tegra/bpmp-abi.h> |
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#include <soc/tegra/bpmp.h> |
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/* |
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* Serialized I2C message header size is 6 bytes and includes address, flags |
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* and length |
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*/ |
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#define SERIALI2C_HDR_SIZE 6 |
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struct tegra_bpmp_i2c { |
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struct i2c_adapter adapter; |
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struct device *dev; |
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struct tegra_bpmp *bpmp; |
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unsigned int bus; |
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}; |
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/* |
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* Linux flags are translated to BPMP defined I2C flags that are used in BPMP |
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* firmware I2C driver to avoid any issues in future if Linux I2C flags are |
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* changed. |
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*/ |
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static void tegra_bpmp_xlate_flags(u16 flags, u16 *out) |
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{ |
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if (flags & I2C_M_TEN) |
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*out |= SERIALI2C_TEN; |
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if (flags & I2C_M_RD) |
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*out |= SERIALI2C_RD; |
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if (flags & I2C_M_STOP) |
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*out |= SERIALI2C_STOP; |
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if (flags & I2C_M_NOSTART) |
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*out |= SERIALI2C_NOSTART; |
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if (flags & I2C_M_REV_DIR_ADDR) |
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*out |= SERIALI2C_REV_DIR_ADDR; |
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if (flags & I2C_M_IGNORE_NAK) |
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*out |= SERIALI2C_IGNORE_NAK; |
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if (flags & I2C_M_NO_RD_ACK) |
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*out |= SERIALI2C_NO_RD_ACK; |
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if (flags & I2C_M_RECV_LEN) |
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*out |= SERIALI2C_RECV_LEN; |
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} |
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/* |
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* The serialized I2C format is simply the following: |
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* [addr little-endian][flags little-endian][len little-endian][data if write] |
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* [addr little-endian][flags little-endian][len little-endian][data if write] |
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* ... |
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* |
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* The flags are translated from Linux kernel representation to seriali2c |
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* representation. Any undefined flag being set causes an error. |
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* |
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* The data is there only for writes. Reads have the data transferred in the |
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* other direction, and thus data is not present. |
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* |
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* See deserialize_i2c documentation for the data format in the other direction. |
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*/ |
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static void tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c, |
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struct mrq_i2c_request *request, |
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struct i2c_msg *msgs, |
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unsigned int num) |
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{ |
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char *buf = request->xfer.data_buf; |
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unsigned int i, j, pos = 0; |
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for (i = 0; i < num; i++) { |
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struct i2c_msg *msg = &msgs[i]; |
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u16 flags = 0; |
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tegra_bpmp_xlate_flags(msg->flags, &flags); |
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buf[pos++] = msg->addr & 0xff; |
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buf[pos++] = (msg->addr & 0xff00) >> 8; |
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buf[pos++] = flags & 0xff; |
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buf[pos++] = (flags & 0xff00) >> 8; |
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buf[pos++] = msg->len & 0xff; |
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buf[pos++] = (msg->len & 0xff00) >> 8; |
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if ((flags & SERIALI2C_RD) == 0) { |
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for (j = 0; j < msg->len; j++) |
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buf[pos++] = msg->buf[j]; |
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} |
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} |
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request->xfer.data_size = pos; |
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} |
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/* |
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* The data in the BPMP -> CPU direction is composed of sequential blocks for |
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* those messages that have I2C_M_RD. So, for example, if you have: |
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* |
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* - !I2C_M_RD, len == 5, data == a0 01 02 03 04 |
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* - !I2C_M_RD, len == 1, data == a0 |
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* - I2C_M_RD, len == 2, data == [uninitialized buffer 1] |
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* - !I2C_M_RD, len == 1, data == a2 |
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* - I2C_M_RD, len == 2, data == [uninitialized buffer 2] |
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* |
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* ...then the data in the BPMP -> CPU direction would be 4 bytes total, and |
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* would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes |
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* that will go to uninitialized buffer 2. |
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*/ |
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static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c, |
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struct mrq_i2c_response *response, |
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struct i2c_msg *msgs, |
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unsigned int num) |
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{ |
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size_t size = response->xfer.data_size, len = 0, pos = 0; |
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char *buf = response->xfer.data_buf; |
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unsigned int i; |
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for (i = 0; i < num; i++) |
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if (msgs[i].flags & I2C_M_RD) |
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len += msgs[i].len; |
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if (len != size) |
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return -EINVAL; |
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for (i = 0; i < num; i++) { |
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if (msgs[i].flags & I2C_M_RD) { |
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memcpy(msgs[i].buf, buf + pos, msgs[i].len); |
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pos += msgs[i].len; |
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} |
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} |
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return 0; |
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} |
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static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num) |
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{ |
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size_t tx_len = 0, rx_len = 0; |
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unsigned int i; |
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for (i = 0; i < num; i++) |
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if (!(msgs[i].flags & I2C_M_RD)) |
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tx_len += SERIALI2C_HDR_SIZE + msgs[i].len; |
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if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE) |
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return -EINVAL; |
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for (i = 0; i < num; i++) |
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if ((msgs[i].flags & I2C_M_RD)) |
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rx_len += msgs[i].len; |
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if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE) |
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return -EINVAL; |
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return 0; |
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} |
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static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c, |
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struct mrq_i2c_request *request, |
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struct mrq_i2c_response *response, |
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bool atomic) |
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{ |
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struct tegra_bpmp_message msg; |
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int err; |
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request->cmd = CMD_I2C_XFER; |
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request->xfer.bus_id = i2c->bus; |
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memset(&msg, 0, sizeof(msg)); |
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msg.mrq = MRQ_I2C; |
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msg.tx.data = request; |
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msg.tx.size = sizeof(*request); |
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msg.rx.data = response; |
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msg.rx.size = sizeof(*response); |
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if (atomic) |
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err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg); |
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else |
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err = tegra_bpmp_transfer(i2c->bpmp, &msg); |
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if (err < 0) { |
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dev_err(i2c->dev, "failed to transfer message: %d\n", err); |
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return err; |
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} |
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if (msg.rx.ret != 0) { |
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if (msg.rx.ret == -BPMP_EAGAIN) { |
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dev_dbg(i2c->dev, "arbitration lost\n"); |
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return -EAGAIN; |
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} |
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if (msg.rx.ret == -BPMP_ETIMEDOUT) { |
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dev_dbg(i2c->dev, "timeout\n"); |
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return -ETIMEDOUT; |
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} |
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if (msg.rx.ret == -BPMP_ENXIO) { |
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dev_dbg(i2c->dev, "NAK\n"); |
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return -ENXIO; |
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} |
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dev_err(i2c->dev, "transaction failed: %d\n", msg.rx.ret); |
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return -EIO; |
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} |
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return 0; |
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} |
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static int tegra_bpmp_i2c_xfer_common(struct i2c_adapter *adapter, |
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struct i2c_msg *msgs, int num, |
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bool atomic) |
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{ |
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struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter); |
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struct mrq_i2c_response response; |
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struct mrq_i2c_request request; |
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int err; |
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err = tegra_bpmp_i2c_msg_len_check(msgs, num); |
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if (err < 0) { |
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dev_err(i2c->dev, "unsupported message length\n"); |
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return err; |
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} |
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memset(&request, 0, sizeof(request)); |
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memset(&response, 0, sizeof(response)); |
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tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num); |
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err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response, atomic); |
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if (err < 0) { |
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dev_err(i2c->dev, "failed to transfer message: %d\n", err); |
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return err; |
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} |
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err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num); |
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if (err < 0) { |
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dev_err(i2c->dev, "failed to deserialize message: %d\n", err); |
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return err; |
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} |
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return num; |
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} |
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static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter, |
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struct i2c_msg *msgs, int num) |
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{ |
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return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, false); |
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} |
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static int tegra_bpmp_i2c_xfer_atomic(struct i2c_adapter *adapter, |
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struct i2c_msg *msgs, int num) |
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{ |
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return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, true); |
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} |
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static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter) |
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{ |
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return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | |
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I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART; |
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} |
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static const struct i2c_algorithm tegra_bpmp_i2c_algo = { |
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.master_xfer = tegra_bpmp_i2c_xfer, |
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.master_xfer_atomic = tegra_bpmp_i2c_xfer_atomic, |
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.functionality = tegra_bpmp_i2c_func, |
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}; |
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static int tegra_bpmp_i2c_probe(struct platform_device *pdev) |
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{ |
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struct tegra_bpmp_i2c *i2c; |
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u32 value; |
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int err; |
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i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); |
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if (!i2c) |
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return -ENOMEM; |
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i2c->dev = &pdev->dev; |
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i2c->bpmp = dev_get_drvdata(pdev->dev.parent); |
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if (!i2c->bpmp) |
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return -ENODEV; |
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err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id", |
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&value); |
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if (err < 0) |
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return err; |
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i2c->bus = value; |
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i2c_set_adapdata(&i2c->adapter, i2c); |
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i2c->adapter.owner = THIS_MODULE; |
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strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter", |
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sizeof(i2c->adapter.name)); |
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i2c->adapter.algo = &tegra_bpmp_i2c_algo; |
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i2c->adapter.dev.parent = &pdev->dev; |
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i2c->adapter.dev.of_node = pdev->dev.of_node; |
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platform_set_drvdata(pdev, i2c); |
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return i2c_add_adapter(&i2c->adapter); |
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} |
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static int tegra_bpmp_i2c_remove(struct platform_device *pdev) |
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{ |
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struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev); |
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i2c_del_adapter(&i2c->adapter); |
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return 0; |
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} |
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static const struct of_device_id tegra_bpmp_i2c_of_match[] = { |
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{ .compatible = "nvidia,tegra186-bpmp-i2c", }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match); |
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static struct platform_driver tegra_bpmp_i2c_driver = { |
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.driver = { |
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.name = "tegra-bpmp-i2c", |
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.of_match_table = tegra_bpmp_i2c_of_match, |
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}, |
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.probe = tegra_bpmp_i2c_probe, |
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.remove = tegra_bpmp_i2c_remove, |
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}; |
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module_platform_driver(tegra_bpmp_i2c_driver); |
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MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver"); |
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MODULE_AUTHOR("Shardar Shariff Md <[email protected]>"); |
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MODULE_AUTHOR("Juha-Matti Tilli"); |
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MODULE_LICENSE("GPL v2");
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