518 lines
14 KiB
C
518 lines
14 KiB
C
/*
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* Copyright (C) 2014 Broadcom Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation version 2.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of 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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#include <linux/delay.h>
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#include <linux/i2c.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#define CFG_OFFSET 0x00
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#define CFG_RESET_SHIFT 31
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#define CFG_EN_SHIFT 30
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#define CFG_M_RETRY_CNT_SHIFT 16
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#define CFG_M_RETRY_CNT_MASK 0x0f
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#define TIM_CFG_OFFSET 0x04
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#define TIM_CFG_MODE_400_SHIFT 31
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#define M_FIFO_CTRL_OFFSET 0x0c
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#define M_FIFO_RX_FLUSH_SHIFT 31
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#define M_FIFO_TX_FLUSH_SHIFT 30
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#define M_FIFO_RX_CNT_SHIFT 16
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#define M_FIFO_RX_CNT_MASK 0x7f
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#define M_FIFO_RX_THLD_SHIFT 8
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#define M_FIFO_RX_THLD_MASK 0x3f
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#define M_CMD_OFFSET 0x30
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#define M_CMD_START_BUSY_SHIFT 31
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#define M_CMD_STATUS_SHIFT 25
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#define M_CMD_STATUS_MASK 0x07
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#define M_CMD_STATUS_SUCCESS 0x0
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#define M_CMD_STATUS_LOST_ARB 0x1
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#define M_CMD_STATUS_NACK_ADDR 0x2
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#define M_CMD_STATUS_NACK_DATA 0x3
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#define M_CMD_STATUS_TIMEOUT 0x4
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#define M_CMD_PROTOCOL_SHIFT 9
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#define M_CMD_PROTOCOL_MASK 0xf
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#define M_CMD_PROTOCOL_BLK_WR 0x7
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#define M_CMD_PROTOCOL_BLK_RD 0x8
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#define M_CMD_PEC_SHIFT 8
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#define M_CMD_RD_CNT_SHIFT 0
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#define M_CMD_RD_CNT_MASK 0xff
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#define IE_OFFSET 0x38
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#define IE_M_RX_FIFO_FULL_SHIFT 31
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#define IE_M_RX_THLD_SHIFT 30
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#define IE_M_START_BUSY_SHIFT 28
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#define IS_OFFSET 0x3c
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#define IS_M_RX_FIFO_FULL_SHIFT 31
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#define IS_M_RX_THLD_SHIFT 30
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#define IS_M_START_BUSY_SHIFT 28
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#define M_TX_OFFSET 0x40
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#define M_TX_WR_STATUS_SHIFT 31
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#define M_TX_DATA_SHIFT 0
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#define M_TX_DATA_MASK 0xff
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#define M_RX_OFFSET 0x44
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#define M_RX_STATUS_SHIFT 30
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#define M_RX_STATUS_MASK 0x03
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#define M_RX_PEC_ERR_SHIFT 29
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#define M_RX_DATA_SHIFT 0
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#define M_RX_DATA_MASK 0xff
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#define I2C_TIMEOUT_MESC 100
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#define M_TX_RX_FIFO_SIZE 64
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enum bus_speed_index {
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I2C_SPD_100K = 0,
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I2C_SPD_400K,
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};
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struct bcm_iproc_i2c_dev {
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struct device *device;
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int irq;
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void __iomem *base;
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struct i2c_adapter adapter;
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unsigned int bus_speed;
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struct completion done;
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int xfer_is_done;
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};
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/*
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* Can be expanded in the future if more interrupt status bits are utilized
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*/
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#define ISR_MASK (1 << IS_M_START_BUSY_SHIFT)
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static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data)
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{
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struct bcm_iproc_i2c_dev *iproc_i2c = data;
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u32 status = readl(iproc_i2c->base + IS_OFFSET);
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status &= ISR_MASK;
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if (!status)
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return IRQ_NONE;
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writel(status, iproc_i2c->base + IS_OFFSET);
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iproc_i2c->xfer_is_done = 1;
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complete_all(&iproc_i2c->done);
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return IRQ_HANDLED;
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}
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static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *iproc_i2c,
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struct i2c_msg *msg)
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{
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u32 val;
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val = readl(iproc_i2c->base + M_CMD_OFFSET);
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val = (val >> M_CMD_STATUS_SHIFT) & M_CMD_STATUS_MASK;
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switch (val) {
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case M_CMD_STATUS_SUCCESS:
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return 0;
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case M_CMD_STATUS_LOST_ARB:
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dev_dbg(iproc_i2c->device, "lost bus arbitration\n");
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return -EAGAIN;
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case M_CMD_STATUS_NACK_ADDR:
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dev_dbg(iproc_i2c->device, "NAK addr:0x%02x\n", msg->addr);
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return -ENXIO;
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case M_CMD_STATUS_NACK_DATA:
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dev_dbg(iproc_i2c->device, "NAK data\n");
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return -ENXIO;
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case M_CMD_STATUS_TIMEOUT:
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dev_dbg(iproc_i2c->device, "bus timeout\n");
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return -ETIMEDOUT;
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default:
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dev_dbg(iproc_i2c->device, "unknown error code=%d\n", val);
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return -EIO;
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}
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}
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static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
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struct i2c_msg *msg)
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{
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int ret, i;
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u8 addr;
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u32 val;
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unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MESC);
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/* check if bus is busy */
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if (!!(readl(iproc_i2c->base + M_CMD_OFFSET) &
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BIT(M_CMD_START_BUSY_SHIFT))) {
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dev_warn(iproc_i2c->device, "bus is busy\n");
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return -EBUSY;
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}
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/* format and load slave address into the TX FIFO */
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addr = msg->addr << 1 | (msg->flags & I2C_M_RD ? 1 : 0);
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writel(addr, iproc_i2c->base + M_TX_OFFSET);
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/* for a write transaction, load data into the TX FIFO */
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if (!(msg->flags & I2C_M_RD)) {
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for (i = 0; i < msg->len; i++) {
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val = msg->buf[i];
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/* mark the last byte */
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if (i == msg->len - 1)
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val |= 1 << M_TX_WR_STATUS_SHIFT;
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writel(val, iproc_i2c->base + M_TX_OFFSET);
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}
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}
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/* mark as incomplete before starting the transaction */
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reinit_completion(&iproc_i2c->done);
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iproc_i2c->xfer_is_done = 0;
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/*
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* Enable the "start busy" interrupt, which will be triggered after the
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* transaction is done, i.e., the internal start_busy bit, transitions
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* from 1 to 0.
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*/
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writel(1 << IE_M_START_BUSY_SHIFT, iproc_i2c->base + IE_OFFSET);
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/*
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* Now we can activate the transfer. For a read operation, specify the
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* number of bytes to read
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*/
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val = 1 << M_CMD_START_BUSY_SHIFT;
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if (msg->flags & I2C_M_RD) {
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val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) |
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(msg->len << M_CMD_RD_CNT_SHIFT);
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} else {
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val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT);
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}
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writel(val, iproc_i2c->base + M_CMD_OFFSET);
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time_left = wait_for_completion_timeout(&iproc_i2c->done, time_left);
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/* disable all interrupts */
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writel(0, iproc_i2c->base + IE_OFFSET);
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/* read it back to flush the write */
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readl(iproc_i2c->base + IE_OFFSET);
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/* make sure the interrupt handler isn't running */
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synchronize_irq(iproc_i2c->irq);
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if (!time_left && !iproc_i2c->xfer_is_done) {
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dev_err(iproc_i2c->device, "transaction timed out\n");
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/* flush FIFOs */
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val = (1 << M_FIFO_RX_FLUSH_SHIFT) |
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(1 << M_FIFO_TX_FLUSH_SHIFT);
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writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET);
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return -ETIMEDOUT;
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}
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ret = bcm_iproc_i2c_check_status(iproc_i2c, msg);
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if (ret) {
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/* flush both TX/RX FIFOs */
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val = (1 << M_FIFO_RX_FLUSH_SHIFT) |
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(1 << M_FIFO_TX_FLUSH_SHIFT);
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writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET);
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return ret;
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}
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/*
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* For a read operation, we now need to load the data from FIFO
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* into the memory buffer
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*/
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if (msg->flags & I2C_M_RD) {
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for (i = 0; i < msg->len; i++) {
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msg->buf[i] = (readl(iproc_i2c->base + M_RX_OFFSET) >>
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M_RX_DATA_SHIFT) & M_RX_DATA_MASK;
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}
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}
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return 0;
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}
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static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter,
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struct i2c_msg msgs[], int num)
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{
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struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adapter);
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int ret, i;
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/* go through all messages */
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for (i = 0; i < num; i++) {
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ret = bcm_iproc_i2c_xfer_single_msg(iproc_i2c, &msgs[i]);
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if (ret) {
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dev_dbg(iproc_i2c->device, "xfer failed\n");
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return ret;
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}
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}
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return num;
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}
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static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap)
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{
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return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
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}
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static const struct i2c_algorithm bcm_iproc_algo = {
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.master_xfer = bcm_iproc_i2c_xfer,
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.functionality = bcm_iproc_i2c_functionality,
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};
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static struct i2c_adapter_quirks bcm_iproc_i2c_quirks = {
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/* need to reserve one byte in the FIFO for the slave address */
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.max_read_len = M_TX_RX_FIFO_SIZE - 1,
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.max_write_len = M_TX_RX_FIFO_SIZE - 1,
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};
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static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c)
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{
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unsigned int bus_speed;
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u32 val;
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int ret = of_property_read_u32(iproc_i2c->device->of_node,
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"clock-frequency", &bus_speed);
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if (ret < 0) {
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dev_info(iproc_i2c->device,
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"unable to interpret clock-frequency DT property\n");
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bus_speed = 100000;
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}
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if (bus_speed < 100000) {
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dev_err(iproc_i2c->device, "%d Hz bus speed not supported\n",
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bus_speed);
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dev_err(iproc_i2c->device,
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"valid speeds are 100khz and 400khz\n");
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return -EINVAL;
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} else if (bus_speed < 400000) {
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bus_speed = 100000;
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} else {
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bus_speed = 400000;
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}
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iproc_i2c->bus_speed = bus_speed;
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val = readl(iproc_i2c->base + TIM_CFG_OFFSET);
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val &= ~(1 << TIM_CFG_MODE_400_SHIFT);
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val |= (bus_speed == 400000) << TIM_CFG_MODE_400_SHIFT;
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writel(val, iproc_i2c->base + TIM_CFG_OFFSET);
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dev_info(iproc_i2c->device, "bus set to %u Hz\n", bus_speed);
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return 0;
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}
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static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *iproc_i2c)
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{
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u32 val;
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/* put controller in reset */
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val = readl(iproc_i2c->base + CFG_OFFSET);
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val |= 1 << CFG_RESET_SHIFT;
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val &= ~(1 << CFG_EN_SHIFT);
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writel(val, iproc_i2c->base + CFG_OFFSET);
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/* wait 100 usec per spec */
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udelay(100);
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/* bring controller out of reset */
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val &= ~(1 << CFG_RESET_SHIFT);
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writel(val, iproc_i2c->base + CFG_OFFSET);
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/* flush TX/RX FIFOs and set RX FIFO threshold to zero */
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val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT);
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writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET);
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/* disable all interrupts */
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writel(0, iproc_i2c->base + IE_OFFSET);
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/* clear all pending interrupts */
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writel(0xffffffff, iproc_i2c->base + IS_OFFSET);
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return 0;
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}
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static void bcm_iproc_i2c_enable_disable(struct bcm_iproc_i2c_dev *iproc_i2c,
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bool enable)
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{
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u32 val;
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val = readl(iproc_i2c->base + CFG_OFFSET);
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if (enable)
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val |= BIT(CFG_EN_SHIFT);
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else
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val &= ~BIT(CFG_EN_SHIFT);
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writel(val, iproc_i2c->base + CFG_OFFSET);
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}
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static int bcm_iproc_i2c_probe(struct platform_device *pdev)
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{
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int irq, ret = 0;
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struct bcm_iproc_i2c_dev *iproc_i2c;
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struct i2c_adapter *adap;
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struct resource *res;
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iproc_i2c = devm_kzalloc(&pdev->dev, sizeof(*iproc_i2c),
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GFP_KERNEL);
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if (!iproc_i2c)
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return -ENOMEM;
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platform_set_drvdata(pdev, iproc_i2c);
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iproc_i2c->device = &pdev->dev;
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init_completion(&iproc_i2c->done);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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iproc_i2c->base = devm_ioremap_resource(iproc_i2c->device, res);
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if (IS_ERR(iproc_i2c->base))
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return PTR_ERR(iproc_i2c->base);
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ret = bcm_iproc_i2c_init(iproc_i2c);
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if (ret)
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return ret;
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ret = bcm_iproc_i2c_cfg_speed(iproc_i2c);
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if (ret)
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return ret;
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irq = platform_get_irq(pdev, 0);
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if (irq <= 0) {
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dev_err(iproc_i2c->device, "no irq resource\n");
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return irq;
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}
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iproc_i2c->irq = irq;
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ret = devm_request_irq(iproc_i2c->device, irq, bcm_iproc_i2c_isr, 0,
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pdev->name, iproc_i2c);
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if (ret < 0) {
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dev_err(iproc_i2c->device, "unable to request irq %i\n", irq);
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return ret;
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}
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bcm_iproc_i2c_enable_disable(iproc_i2c, true);
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adap = &iproc_i2c->adapter;
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i2c_set_adapdata(adap, iproc_i2c);
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strlcpy(adap->name, "Broadcom iProc I2C adapter", sizeof(adap->name));
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adap->algo = &bcm_iproc_algo;
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adap->quirks = &bcm_iproc_i2c_quirks;
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adap->dev.parent = &pdev->dev;
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adap->dev.of_node = pdev->dev.of_node;
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ret = i2c_add_adapter(adap);
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if (ret) {
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dev_err(iproc_i2c->device, "failed to add adapter\n");
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return ret;
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}
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return 0;
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}
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static int bcm_iproc_i2c_remove(struct platform_device *pdev)
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{
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struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev);
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/* make sure there's no pending interrupt when we remove the adapter */
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writel(0, iproc_i2c->base + IE_OFFSET);
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readl(iproc_i2c->base + IE_OFFSET);
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synchronize_irq(iproc_i2c->irq);
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i2c_del_adapter(&iproc_i2c->adapter);
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bcm_iproc_i2c_enable_disable(iproc_i2c, false);
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int bcm_iproc_i2c_suspend(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev);
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/* make sure there's no pending interrupt when we go into suspend */
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writel(0, iproc_i2c->base + IE_OFFSET);
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readl(iproc_i2c->base + IE_OFFSET);
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synchronize_irq(iproc_i2c->irq);
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/* now disable the controller */
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bcm_iproc_i2c_enable_disable(iproc_i2c, false);
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return 0;
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}
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static int bcm_iproc_i2c_resume(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev);
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int ret;
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u32 val;
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/*
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* Power domain could have been shut off completely in system deep
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* sleep, so re-initialize the block here
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*/
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ret = bcm_iproc_i2c_init(iproc_i2c);
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if (ret)
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return ret;
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/* configure to the desired bus speed */
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val = readl(iproc_i2c->base + TIM_CFG_OFFSET);
|
|
val &= ~(1 << TIM_CFG_MODE_400_SHIFT);
|
|
val |= (iproc_i2c->bus_speed == 400000) << TIM_CFG_MODE_400_SHIFT;
|
|
writel(val, iproc_i2c->base + TIM_CFG_OFFSET);
|
|
|
|
bcm_iproc_i2c_enable_disable(iproc_i2c, true);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct dev_pm_ops bcm_iproc_i2c_pm_ops = {
|
|
.suspend_late = &bcm_iproc_i2c_suspend,
|
|
.resume_early = &bcm_iproc_i2c_resume
|
|
};
|
|
|
|
#define BCM_IPROC_I2C_PM_OPS (&bcm_iproc_i2c_pm_ops)
|
|
#else
|
|
#define BCM_IPROC_I2C_PM_OPS NULL
|
|
#endif /* CONFIG_PM_SLEEP */
|
|
|
|
static const struct of_device_id bcm_iproc_i2c_of_match[] = {
|
|
{ .compatible = "brcm,iproc-i2c" },
|
|
{ /* sentinel */ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, bcm_iproc_i2c_of_match);
|
|
|
|
static struct platform_driver bcm_iproc_i2c_driver = {
|
|
.driver = {
|
|
.name = "bcm-iproc-i2c",
|
|
.of_match_table = bcm_iproc_i2c_of_match,
|
|
.pm = BCM_IPROC_I2C_PM_OPS,
|
|
},
|
|
.probe = bcm_iproc_i2c_probe,
|
|
.remove = bcm_iproc_i2c_remove,
|
|
};
|
|
module_platform_driver(bcm_iproc_i2c_driver);
|
|
|
|
MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
|
|
MODULE_DESCRIPTION("Broadcom iProc I2C Driver");
|
|
MODULE_LICENSE("GPL v2");
|