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469 lines
12 KiB
469 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2014 Uwe Kleine-Koenig for Pengutronix |
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*/ |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/i2c.h> |
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#include <linux/io.h> |
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#include <linux/interrupt.h> |
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#include <linux/err.h> |
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#include <linux/clk.h> |
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#define DRIVER_NAME "efm32-i2c" |
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#define MASK_VAL(mask, val) ((val << __ffs(mask)) & mask) |
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#define REG_CTRL 0x00 |
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#define REG_CTRL_EN 0x00001 |
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#define REG_CTRL_SLAVE 0x00002 |
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#define REG_CTRL_AUTOACK 0x00004 |
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#define REG_CTRL_AUTOSE 0x00008 |
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#define REG_CTRL_AUTOSN 0x00010 |
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#define REG_CTRL_ARBDIS 0x00020 |
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#define REG_CTRL_GCAMEN 0x00040 |
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#define REG_CTRL_CLHR__MASK 0x00300 |
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#define REG_CTRL_BITO__MASK 0x03000 |
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#define REG_CTRL_BITO_OFF 0x00000 |
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#define REG_CTRL_BITO_40PCC 0x01000 |
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#define REG_CTRL_BITO_80PCC 0x02000 |
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#define REG_CTRL_BITO_160PCC 0x03000 |
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#define REG_CTRL_GIBITO 0x08000 |
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#define REG_CTRL_CLTO__MASK 0x70000 |
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#define REG_CTRL_CLTO_OFF 0x00000 |
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#define REG_CMD 0x04 |
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#define REG_CMD_START 0x00001 |
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#define REG_CMD_STOP 0x00002 |
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#define REG_CMD_ACK 0x00004 |
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#define REG_CMD_NACK 0x00008 |
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#define REG_CMD_CONT 0x00010 |
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#define REG_CMD_ABORT 0x00020 |
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#define REG_CMD_CLEARTX 0x00040 |
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#define REG_CMD_CLEARPC 0x00080 |
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#define REG_STATE 0x08 |
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#define REG_STATE_BUSY 0x00001 |
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#define REG_STATE_MASTER 0x00002 |
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#define REG_STATE_TRANSMITTER 0x00004 |
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#define REG_STATE_NACKED 0x00008 |
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#define REG_STATE_BUSHOLD 0x00010 |
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#define REG_STATE_STATE__MASK 0x000e0 |
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#define REG_STATE_STATE_IDLE 0x00000 |
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#define REG_STATE_STATE_WAIT 0x00020 |
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#define REG_STATE_STATE_START 0x00040 |
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#define REG_STATE_STATE_ADDR 0x00060 |
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#define REG_STATE_STATE_ADDRACK 0x00080 |
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#define REG_STATE_STATE_DATA 0x000a0 |
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#define REG_STATE_STATE_DATAACK 0x000c0 |
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#define REG_STATUS 0x0c |
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#define REG_STATUS_PSTART 0x00001 |
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#define REG_STATUS_PSTOP 0x00002 |
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#define REG_STATUS_PACK 0x00004 |
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#define REG_STATUS_PNACK 0x00008 |
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#define REG_STATUS_PCONT 0x00010 |
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#define REG_STATUS_PABORT 0x00020 |
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#define REG_STATUS_TXC 0x00040 |
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#define REG_STATUS_TXBL 0x00080 |
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#define REG_STATUS_RXDATAV 0x00100 |
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#define REG_CLKDIV 0x10 |
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#define REG_CLKDIV_DIV__MASK 0x001ff |
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#define REG_CLKDIV_DIV(div) MASK_VAL(REG_CLKDIV_DIV__MASK, (div)) |
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#define REG_SADDR 0x14 |
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#define REG_SADDRMASK 0x18 |
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#define REG_RXDATA 0x1c |
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#define REG_RXDATAP 0x20 |
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#define REG_TXDATA 0x24 |
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#define REG_IF 0x28 |
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#define REG_IF_START 0x00001 |
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#define REG_IF_RSTART 0x00002 |
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#define REG_IF_ADDR 0x00004 |
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#define REG_IF_TXC 0x00008 |
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#define REG_IF_TXBL 0x00010 |
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#define REG_IF_RXDATAV 0x00020 |
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#define REG_IF_ACK 0x00040 |
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#define REG_IF_NACK 0x00080 |
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#define REG_IF_MSTOP 0x00100 |
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#define REG_IF_ARBLOST 0x00200 |
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#define REG_IF_BUSERR 0x00400 |
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#define REG_IF_BUSHOLD 0x00800 |
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#define REG_IF_TXOF 0x01000 |
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#define REG_IF_RXUF 0x02000 |
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#define REG_IF_BITO 0x04000 |
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#define REG_IF_CLTO 0x08000 |
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#define REG_IF_SSTOP 0x10000 |
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#define REG_IFS 0x2c |
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#define REG_IFC 0x30 |
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#define REG_IFC__MASK 0x1ffcf |
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#define REG_IEN 0x34 |
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#define REG_ROUTE 0x38 |
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#define REG_ROUTE_SDAPEN 0x00001 |
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#define REG_ROUTE_SCLPEN 0x00002 |
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#define REG_ROUTE_LOCATION__MASK 0x00700 |
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#define REG_ROUTE_LOCATION(n) MASK_VAL(REG_ROUTE_LOCATION__MASK, (n)) |
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struct efm32_i2c_ddata { |
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struct i2c_adapter adapter; |
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struct clk *clk; |
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void __iomem *base; |
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unsigned int irq; |
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u8 location; |
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unsigned long frequency; |
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/* transfer data */ |
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struct completion done; |
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struct i2c_msg *msgs; |
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size_t num_msgs; |
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size_t current_word, current_msg; |
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int retval; |
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}; |
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static u32 efm32_i2c_read32(struct efm32_i2c_ddata *ddata, unsigned offset) |
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{ |
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return readl(ddata->base + offset); |
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} |
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static void efm32_i2c_write32(struct efm32_i2c_ddata *ddata, |
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unsigned offset, u32 value) |
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{ |
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writel(value, ddata->base + offset); |
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} |
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static void efm32_i2c_send_next_msg(struct efm32_i2c_ddata *ddata) |
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{ |
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struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg]; |
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efm32_i2c_write32(ddata, REG_CMD, REG_CMD_START); |
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efm32_i2c_write32(ddata, REG_TXDATA, i2c_8bit_addr_from_msg(cur_msg)); |
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} |
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static void efm32_i2c_send_next_byte(struct efm32_i2c_ddata *ddata) |
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{ |
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struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg]; |
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if (ddata->current_word >= cur_msg->len) { |
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/* cur_msg completely transferred */ |
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ddata->current_word = 0; |
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ddata->current_msg += 1; |
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if (ddata->current_msg >= ddata->num_msgs) { |
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efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP); |
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complete(&ddata->done); |
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} else { |
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efm32_i2c_send_next_msg(ddata); |
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} |
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} else { |
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efm32_i2c_write32(ddata, REG_TXDATA, |
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cur_msg->buf[ddata->current_word++]); |
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} |
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} |
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static void efm32_i2c_recv_next_byte(struct efm32_i2c_ddata *ddata) |
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{ |
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struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg]; |
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cur_msg->buf[ddata->current_word] = efm32_i2c_read32(ddata, REG_RXDATA); |
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ddata->current_word += 1; |
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if (ddata->current_word >= cur_msg->len) { |
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/* cur_msg completely transferred */ |
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ddata->current_word = 0; |
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ddata->current_msg += 1; |
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efm32_i2c_write32(ddata, REG_CMD, REG_CMD_NACK); |
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if (ddata->current_msg >= ddata->num_msgs) { |
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efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP); |
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complete(&ddata->done); |
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} else { |
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efm32_i2c_send_next_msg(ddata); |
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} |
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} else { |
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efm32_i2c_write32(ddata, REG_CMD, REG_CMD_ACK); |
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} |
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} |
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static irqreturn_t efm32_i2c_irq(int irq, void *dev_id) |
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{ |
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struct efm32_i2c_ddata *ddata = dev_id; |
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struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg]; |
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u32 irqflag = efm32_i2c_read32(ddata, REG_IF); |
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u32 state = efm32_i2c_read32(ddata, REG_STATE); |
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efm32_i2c_write32(ddata, REG_IFC, irqflag & REG_IFC__MASK); |
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switch (state & REG_STATE_STATE__MASK) { |
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case REG_STATE_STATE_IDLE: |
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/* arbitration lost? */ |
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ddata->retval = -EAGAIN; |
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complete(&ddata->done); |
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break; |
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case REG_STATE_STATE_WAIT: |
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/* |
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* huh, this shouldn't happen. |
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* Reset hardware state and get out |
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*/ |
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ddata->retval = -EIO; |
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efm32_i2c_write32(ddata, REG_CMD, |
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REG_CMD_STOP | REG_CMD_ABORT | |
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REG_CMD_CLEARTX | REG_CMD_CLEARPC); |
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complete(&ddata->done); |
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break; |
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case REG_STATE_STATE_START: |
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/* "caller" is expected to send an address */ |
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break; |
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case REG_STATE_STATE_ADDR: |
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/* wait for Ack or NAck of slave */ |
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break; |
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case REG_STATE_STATE_ADDRACK: |
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if (state & REG_STATE_NACKED) { |
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efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP); |
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ddata->retval = -ENXIO; |
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complete(&ddata->done); |
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} else if (cur_msg->flags & I2C_M_RD) { |
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/* wait for slave to send first data byte */ |
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} else { |
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efm32_i2c_send_next_byte(ddata); |
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} |
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break; |
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case REG_STATE_STATE_DATA: |
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if (cur_msg->flags & I2C_M_RD) { |
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efm32_i2c_recv_next_byte(ddata); |
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} else { |
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/* wait for Ack or Nack of slave */ |
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} |
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break; |
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case REG_STATE_STATE_DATAACK: |
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if (state & REG_STATE_NACKED) { |
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efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP); |
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complete(&ddata->done); |
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} else { |
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efm32_i2c_send_next_byte(ddata); |
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} |
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} |
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return IRQ_HANDLED; |
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} |
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static int efm32_i2c_master_xfer(struct i2c_adapter *adap, |
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struct i2c_msg *msgs, int num) |
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{ |
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struct efm32_i2c_ddata *ddata = i2c_get_adapdata(adap); |
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int ret; |
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if (ddata->msgs) |
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return -EBUSY; |
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ddata->msgs = msgs; |
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ddata->num_msgs = num; |
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ddata->current_word = 0; |
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ddata->current_msg = 0; |
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ddata->retval = -EIO; |
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reinit_completion(&ddata->done); |
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dev_dbg(&ddata->adapter.dev, "state: %08x, status: %08x\n", |
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efm32_i2c_read32(ddata, REG_STATE), |
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efm32_i2c_read32(ddata, REG_STATUS)); |
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efm32_i2c_send_next_msg(ddata); |
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wait_for_completion(&ddata->done); |
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if (ddata->current_msg >= ddata->num_msgs) |
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ret = ddata->num_msgs; |
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else |
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ret = ddata->retval; |
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return ret; |
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} |
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static u32 efm32_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 efm32_i2c_algo = { |
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.master_xfer = efm32_i2c_master_xfer, |
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.functionality = efm32_i2c_functionality, |
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}; |
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static u32 efm32_i2c_get_configured_location(struct efm32_i2c_ddata *ddata) |
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{ |
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u32 reg = efm32_i2c_read32(ddata, REG_ROUTE); |
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return (reg & REG_ROUTE_LOCATION__MASK) >> |
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__ffs(REG_ROUTE_LOCATION__MASK); |
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} |
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static int efm32_i2c_probe(struct platform_device *pdev) |
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{ |
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struct efm32_i2c_ddata *ddata; |
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struct resource *res; |
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unsigned long rate; |
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struct device_node *np = pdev->dev.of_node; |
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u32 location, frequency; |
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int ret; |
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u32 clkdiv; |
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ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL); |
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if (!ddata) |
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return -ENOMEM; |
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platform_set_drvdata(pdev, ddata); |
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init_completion(&ddata->done); |
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strlcpy(ddata->adapter.name, pdev->name, sizeof(ddata->adapter.name)); |
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ddata->adapter.owner = THIS_MODULE; |
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ddata->adapter.algo = &efm32_i2c_algo; |
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ddata->adapter.dev.parent = &pdev->dev; |
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ddata->adapter.dev.of_node = pdev->dev.of_node; |
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i2c_set_adapdata(&ddata->adapter, ddata); |
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ddata->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(ddata->clk)) { |
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ret = PTR_ERR(ddata->clk); |
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dev_err(&pdev->dev, "failed to get clock: %d\n", ret); |
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return ret; |
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} |
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ddata->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); |
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if (IS_ERR(ddata->base)) |
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return PTR_ERR(ddata->base); |
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if (resource_size(res) < 0x42) { |
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dev_err(&pdev->dev, "memory resource too small\n"); |
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return -EINVAL; |
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} |
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ret = platform_get_irq(pdev, 0); |
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if (ret <= 0) { |
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if (!ret) |
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ret = -EINVAL; |
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return ret; |
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} |
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ddata->irq = ret; |
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ret = clk_prepare_enable(ddata->clk); |
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if (ret < 0) { |
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dev_err(&pdev->dev, "failed to enable clock (%d)\n", ret); |
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return ret; |
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} |
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ret = of_property_read_u32(np, "energymicro,location", &location); |
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if (ret) |
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/* fall back to wrongly namespaced property */ |
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ret = of_property_read_u32(np, "efm32,location", &location); |
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if (!ret) { |
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dev_dbg(&pdev->dev, "using location %u\n", location); |
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} else { |
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/* default to location configured in hardware */ |
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location = efm32_i2c_get_configured_location(ddata); |
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dev_info(&pdev->dev, "fall back to location %u\n", location); |
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} |
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ddata->location = location; |
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ret = of_property_read_u32(np, "clock-frequency", &frequency); |
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if (!ret) { |
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dev_dbg(&pdev->dev, "using frequency %u\n", frequency); |
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} else { |
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frequency = I2C_MAX_STANDARD_MODE_FREQ; |
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dev_info(&pdev->dev, "defaulting to 100 kHz\n"); |
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} |
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ddata->frequency = frequency; |
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rate = clk_get_rate(ddata->clk); |
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if (!rate) { |
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dev_err(&pdev->dev, "there is no input clock available\n"); |
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ret = -EINVAL; |
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goto err_disable_clk; |
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} |
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clkdiv = DIV_ROUND_UP(rate, 8 * ddata->frequency) - 1; |
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if (clkdiv >= 0x200) { |
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dev_err(&pdev->dev, |
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"input clock too fast (%lu) to divide down to bus freq (%lu)", |
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rate, ddata->frequency); |
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ret = -EINVAL; |
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goto err_disable_clk; |
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} |
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dev_dbg(&pdev->dev, "input clock = %lu, bus freq = %lu, clkdiv = %lu\n", |
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rate, ddata->frequency, (unsigned long)clkdiv); |
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efm32_i2c_write32(ddata, REG_CLKDIV, REG_CLKDIV_DIV(clkdiv)); |
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efm32_i2c_write32(ddata, REG_ROUTE, REG_ROUTE_SDAPEN | |
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REG_ROUTE_SCLPEN | |
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REG_ROUTE_LOCATION(ddata->location)); |
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efm32_i2c_write32(ddata, REG_CTRL, REG_CTRL_EN | |
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REG_CTRL_BITO_160PCC | 0 * REG_CTRL_GIBITO); |
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efm32_i2c_write32(ddata, REG_IFC, REG_IFC__MASK); |
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efm32_i2c_write32(ddata, REG_IEN, REG_IF_TXC | REG_IF_ACK | REG_IF_NACK |
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| REG_IF_ARBLOST | REG_IF_BUSERR | REG_IF_RXDATAV); |
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/* to make bus idle */ |
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efm32_i2c_write32(ddata, REG_CMD, REG_CMD_ABORT); |
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ret = request_irq(ddata->irq, efm32_i2c_irq, 0, DRIVER_NAME, ddata); |
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if (ret < 0) { |
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dev_err(&pdev->dev, "failed to request irq (%d)\n", ret); |
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goto err_disable_clk; |
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} |
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ret = i2c_add_adapter(&ddata->adapter); |
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if (ret) { |
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free_irq(ddata->irq, ddata); |
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err_disable_clk: |
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clk_disable_unprepare(ddata->clk); |
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} |
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return ret; |
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} |
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static int efm32_i2c_remove(struct platform_device *pdev) |
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{ |
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struct efm32_i2c_ddata *ddata = platform_get_drvdata(pdev); |
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i2c_del_adapter(&ddata->adapter); |
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free_irq(ddata->irq, ddata); |
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clk_disable_unprepare(ddata->clk); |
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return 0; |
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} |
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static const struct of_device_id efm32_i2c_dt_ids[] = { |
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{ |
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.compatible = "energymicro,efm32-i2c", |
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}, { |
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/* sentinel */ |
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} |
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}; |
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MODULE_DEVICE_TABLE(of, efm32_i2c_dt_ids); |
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static struct platform_driver efm32_i2c_driver = { |
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.probe = efm32_i2c_probe, |
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.remove = efm32_i2c_remove, |
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.driver = { |
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.name = DRIVER_NAME, |
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.of_match_table = efm32_i2c_dt_ids, |
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}, |
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}; |
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module_platform_driver(efm32_i2c_driver); |
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MODULE_AUTHOR("Uwe Kleine-Koenig <[email protected]>"); |
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MODULE_DESCRIPTION("EFM32 i2c driver"); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_ALIAS("platform:" DRIVER_NAME);
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