forked from Minki/linux
cadd486cfc
Like the previous w1_io.c reset coments and msleep patch, I don't have the hardware to verify the change, but I think it is safe. It also helps to see a comment like this in the code. "We'll wait a bit longer just to be sure." If they are going to calculate delaying 324.9us, but actually delay 500us, why not just give up the CPU and sleep? This is designed for a battery powered ARM system, avoiding busywaiting has to be good for battery life. I sent a request for testers March 7, 2008 to the Linux kernel mailing list and two developers who have patches for ds1wm.c, but I didn't get any respons. Signed-off-by: David Fries <david@fries.net> Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
473 lines
12 KiB
C
473 lines
12 KiB
C
/*
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* 1-wire busmaster driver for DS1WM and ASICs with embedded DS1WMs
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* such as HP iPAQs (including h5xxx, h2200, and devices with ASIC3
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* like hx4700).
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*
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* Copyright (c) 2004-2005, Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
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* Copyright (c) 2004-2007, Matt Reimer <mreimer@vpop.net>
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*
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* Use consistent with the GNU GPL is permitted,
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* provided that this copyright notice is
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* preserved in its entirety in all copies and derived works.
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*/
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/pm.h>
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#include <linux/platform_device.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/ds1wm.h>
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#include <asm/io.h>
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#include "../w1.h"
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#include "../w1_int.h"
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#define DS1WM_CMD 0x00 /* R/W 4 bits command */
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#define DS1WM_DATA 0x01 /* R/W 8 bits, transmit/receive buffer */
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#define DS1WM_INT 0x02 /* R/W interrupt status */
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#define DS1WM_INT_EN 0x03 /* R/W interrupt enable */
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#define DS1WM_CLKDIV 0x04 /* R/W 5 bits of divisor and pre-scale */
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#define DS1WM_CMD_1W_RESET (1 << 0) /* force reset on 1-wire bus */
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#define DS1WM_CMD_SRA (1 << 1) /* enable Search ROM accelerator mode */
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#define DS1WM_CMD_DQ_OUTPUT (1 << 2) /* write only - forces bus low */
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#define DS1WM_CMD_DQ_INPUT (1 << 3) /* read only - reflects state of bus */
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#define DS1WM_CMD_RST (1 << 5) /* software reset */
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#define DS1WM_CMD_OD (1 << 7) /* overdrive */
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#define DS1WM_INT_PD (1 << 0) /* presence detect */
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#define DS1WM_INT_PDR (1 << 1) /* presence detect result */
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#define DS1WM_INT_TBE (1 << 2) /* tx buffer empty */
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#define DS1WM_INT_TSRE (1 << 3) /* tx shift register empty */
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#define DS1WM_INT_RBF (1 << 4) /* rx buffer full */
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#define DS1WM_INT_RSRF (1 << 5) /* rx shift register full */
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#define DS1WM_INTEN_EPD (1 << 0) /* enable presence detect int */
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#define DS1WM_INTEN_IAS (1 << 1) /* INTR active state */
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#define DS1WM_INTEN_ETBE (1 << 2) /* enable tx buffer empty int */
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#define DS1WM_INTEN_ETMT (1 << 3) /* enable tx shift register empty int */
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#define DS1WM_INTEN_ERBF (1 << 4) /* enable rx buffer full int */
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#define DS1WM_INTEN_ERSRF (1 << 5) /* enable rx shift register full int */
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#define DS1WM_INTEN_DQO (1 << 6) /* enable direct bus driving ops */
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#define DS1WM_TIMEOUT (HZ * 5)
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static struct {
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unsigned long freq;
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unsigned long divisor;
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} freq[] = {
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{ 4000000, 0x8 },
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{ 5000000, 0x2 },
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{ 6000000, 0x5 },
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{ 7000000, 0x3 },
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{ 8000000, 0xc },
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{ 10000000, 0x6 },
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{ 12000000, 0x9 },
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{ 14000000, 0x7 },
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{ 16000000, 0x10 },
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{ 20000000, 0xa },
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{ 24000000, 0xd },
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{ 28000000, 0xb },
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{ 32000000, 0x14 },
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{ 40000000, 0xe },
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{ 48000000, 0x11 },
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{ 56000000, 0xf },
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{ 64000000, 0x18 },
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{ 80000000, 0x12 },
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{ 96000000, 0x15 },
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{ 112000000, 0x13 },
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{ 128000000, 0x1c },
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};
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struct ds1wm_data {
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void __iomem *map;
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int bus_shift; /* # of shifts to calc register offsets */
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struct platform_device *pdev;
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struct ds1wm_platform_data *pdata;
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int irq;
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int active_high;
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struct clk *clk;
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int slave_present;
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void *reset_complete;
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void *read_complete;
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void *write_complete;
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u8 read_byte; /* last byte received */
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};
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static inline void ds1wm_write_register(struct ds1wm_data *ds1wm_data, u32 reg,
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u8 val)
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{
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__raw_writeb(val, ds1wm_data->map + (reg << ds1wm_data->bus_shift));
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}
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static inline u8 ds1wm_read_register(struct ds1wm_data *ds1wm_data, u32 reg)
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{
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return __raw_readb(ds1wm_data->map + (reg << ds1wm_data->bus_shift));
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}
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static irqreturn_t ds1wm_isr(int isr, void *data)
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{
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struct ds1wm_data *ds1wm_data = data;
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u8 intr = ds1wm_read_register(ds1wm_data, DS1WM_INT);
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ds1wm_data->slave_present = (intr & DS1WM_INT_PDR) ? 0 : 1;
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if ((intr & DS1WM_INT_PD) && ds1wm_data->reset_complete)
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complete(ds1wm_data->reset_complete);
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if ((intr & DS1WM_INT_TSRE) && ds1wm_data->write_complete)
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complete(ds1wm_data->write_complete);
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if (intr & DS1WM_INT_RBF) {
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ds1wm_data->read_byte = ds1wm_read_register(ds1wm_data,
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DS1WM_DATA);
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if (ds1wm_data->read_complete)
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complete(ds1wm_data->read_complete);
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}
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return IRQ_HANDLED;
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}
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static int ds1wm_reset(struct ds1wm_data *ds1wm_data)
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{
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unsigned long timeleft;
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DECLARE_COMPLETION_ONSTACK(reset_done);
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ds1wm_data->reset_complete = &reset_done;
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ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, DS1WM_INTEN_EPD |
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(ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0));
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ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_1W_RESET);
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timeleft = wait_for_completion_timeout(&reset_done, DS1WM_TIMEOUT);
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ds1wm_data->reset_complete = NULL;
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if (!timeleft) {
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dev_err(&ds1wm_data->pdev->dev, "reset failed\n");
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return 1;
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}
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/* Wait for the end of the reset. According to the specs, the time
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* from when the interrupt is asserted to the end of the reset is:
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* tRSTH - tPDH - tPDL - tPDI
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* 625 us - 60 us - 240 us - 100 ns = 324.9 us
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*
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* We'll wait a bit longer just to be sure.
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* Was udelay(500), but if it is going to busywait the cpu that long,
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* might as well come back later.
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*/
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msleep(1);
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ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
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DS1WM_INTEN_ERBF | DS1WM_INTEN_ETMT | DS1WM_INTEN_EPD |
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(ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0));
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if (!ds1wm_data->slave_present) {
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dev_dbg(&ds1wm_data->pdev->dev, "reset: no devices found\n");
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return 1;
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}
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return 0;
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}
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static int ds1wm_write(struct ds1wm_data *ds1wm_data, u8 data)
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{
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DECLARE_COMPLETION_ONSTACK(write_done);
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ds1wm_data->write_complete = &write_done;
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ds1wm_write_register(ds1wm_data, DS1WM_DATA, data);
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wait_for_completion_timeout(&write_done, DS1WM_TIMEOUT);
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ds1wm_data->write_complete = NULL;
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return 0;
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}
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static int ds1wm_read(struct ds1wm_data *ds1wm_data, unsigned char write_data)
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{
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DECLARE_COMPLETION_ONSTACK(read_done);
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ds1wm_data->read_complete = &read_done;
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ds1wm_write(ds1wm_data, write_data);
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wait_for_completion_timeout(&read_done, DS1WM_TIMEOUT);
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ds1wm_data->read_complete = NULL;
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return ds1wm_data->read_byte;
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}
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static int ds1wm_find_divisor(int gclk)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(freq); i++)
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if (gclk <= freq[i].freq)
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return freq[i].divisor;
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return 0;
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}
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static void ds1wm_up(struct ds1wm_data *ds1wm_data)
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{
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int gclk, divisor;
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if (ds1wm_data->pdata->enable)
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ds1wm_data->pdata->enable(ds1wm_data->pdev);
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gclk = clk_get_rate(ds1wm_data->clk);
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clk_enable(ds1wm_data->clk);
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divisor = ds1wm_find_divisor(gclk);
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if (divisor == 0) {
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dev_err(&ds1wm_data->pdev->dev,
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"no suitable divisor for %dHz clock\n", gclk);
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return;
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}
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ds1wm_write_register(ds1wm_data, DS1WM_CLKDIV, divisor);
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/* Let the w1 clock stabilize. */
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msleep(1);
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ds1wm_reset(ds1wm_data);
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}
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static void ds1wm_down(struct ds1wm_data *ds1wm_data)
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{
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ds1wm_reset(ds1wm_data);
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/* Disable interrupts. */
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ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
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ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0);
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if (ds1wm_data->pdata->disable)
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ds1wm_data->pdata->disable(ds1wm_data->pdev);
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clk_disable(ds1wm_data->clk);
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}
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/* --------------------------------------------------------------------- */
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/* w1 methods */
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static u8 ds1wm_read_byte(void *data)
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{
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struct ds1wm_data *ds1wm_data = data;
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return ds1wm_read(ds1wm_data, 0xff);
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}
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static void ds1wm_write_byte(void *data, u8 byte)
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{
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struct ds1wm_data *ds1wm_data = data;
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ds1wm_write(ds1wm_data, byte);
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}
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static u8 ds1wm_reset_bus(void *data)
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{
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struct ds1wm_data *ds1wm_data = data;
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ds1wm_reset(ds1wm_data);
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return 0;
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}
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static void ds1wm_search(void *data, struct w1_master *master_dev,
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u8 search_type, w1_slave_found_callback slave_found)
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{
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struct ds1wm_data *ds1wm_data = data;
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int i;
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unsigned long long rom_id;
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/* XXX We need to iterate for multiple devices per the DS1WM docs.
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* See http://www.maxim-ic.com/appnotes.cfm/appnote_number/120. */
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if (ds1wm_reset(ds1wm_data))
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return;
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ds1wm_write(ds1wm_data, search_type);
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ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_SRA);
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for (rom_id = 0, i = 0; i < 16; i++) {
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unsigned char resp, r, d;
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resp = ds1wm_read(ds1wm_data, 0x00);
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r = ((resp & 0x02) >> 1) |
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((resp & 0x08) >> 2) |
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((resp & 0x20) >> 3) |
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((resp & 0x80) >> 4);
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d = ((resp & 0x01) >> 0) |
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((resp & 0x04) >> 1) |
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((resp & 0x10) >> 2) |
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((resp & 0x40) >> 3);
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rom_id |= (unsigned long long) r << (i * 4);
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}
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dev_dbg(&ds1wm_data->pdev->dev, "found 0x%08llX\n", rom_id);
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ds1wm_write_register(ds1wm_data, DS1WM_CMD, ~DS1WM_CMD_SRA);
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ds1wm_reset(ds1wm_data);
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slave_found(master_dev, rom_id);
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}
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/* --------------------------------------------------------------------- */
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static struct w1_bus_master ds1wm_master = {
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.read_byte = ds1wm_read_byte,
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.write_byte = ds1wm_write_byte,
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.reset_bus = ds1wm_reset_bus,
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.search = ds1wm_search,
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};
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static int ds1wm_probe(struct platform_device *pdev)
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{
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struct ds1wm_data *ds1wm_data;
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struct ds1wm_platform_data *plat;
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struct resource *res;
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int ret;
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if (!pdev)
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return -ENODEV;
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ds1wm_data = kzalloc(sizeof(*ds1wm_data), GFP_KERNEL);
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if (!ds1wm_data)
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return -ENOMEM;
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platform_set_drvdata(pdev, ds1wm_data);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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ret = -ENXIO;
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goto err0;
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}
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ds1wm_data->map = ioremap(res->start, res->end - res->start + 1);
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if (!ds1wm_data->map) {
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ret = -ENOMEM;
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goto err0;
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}
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plat = pdev->dev.platform_data;
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ds1wm_data->bus_shift = plat->bus_shift;
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ds1wm_data->pdev = pdev;
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ds1wm_data->pdata = plat;
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res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
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if (!res) {
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ret = -ENXIO;
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goto err1;
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}
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ds1wm_data->irq = res->start;
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ds1wm_data->active_high = plat->active_high;
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if (res->flags & IORESOURCE_IRQ_HIGHEDGE)
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set_irq_type(ds1wm_data->irq, IRQ_TYPE_EDGE_RISING);
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if (res->flags & IORESOURCE_IRQ_LOWEDGE)
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set_irq_type(ds1wm_data->irq, IRQ_TYPE_EDGE_FALLING);
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ret = request_irq(ds1wm_data->irq, ds1wm_isr, IRQF_DISABLED,
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"ds1wm", ds1wm_data);
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if (ret)
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goto err1;
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ds1wm_data->clk = clk_get(&pdev->dev, "ds1wm");
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if (IS_ERR(ds1wm_data->clk)) {
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ret = PTR_ERR(ds1wm_data->clk);
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goto err2;
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}
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ds1wm_up(ds1wm_data);
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ds1wm_master.data = (void *)ds1wm_data;
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ret = w1_add_master_device(&ds1wm_master);
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if (ret)
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goto err3;
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return 0;
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err3:
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ds1wm_down(ds1wm_data);
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clk_put(ds1wm_data->clk);
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err2:
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free_irq(ds1wm_data->irq, ds1wm_data);
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err1:
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iounmap(ds1wm_data->map);
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err0:
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kfree(ds1wm_data);
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return ret;
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}
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#ifdef CONFIG_PM
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static int ds1wm_suspend(struct platform_device *pdev, pm_message_t state)
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{
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struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
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ds1wm_down(ds1wm_data);
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return 0;
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}
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static int ds1wm_resume(struct platform_device *pdev)
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{
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struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
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ds1wm_up(ds1wm_data);
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return 0;
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}
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#else
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#define ds1wm_suspend NULL
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#define ds1wm_resume NULL
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#endif
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static int ds1wm_remove(struct platform_device *pdev)
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{
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struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
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w1_remove_master_device(&ds1wm_master);
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ds1wm_down(ds1wm_data);
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clk_put(ds1wm_data->clk);
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free_irq(ds1wm_data->irq, ds1wm_data);
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iounmap(ds1wm_data->map);
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kfree(ds1wm_data);
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return 0;
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}
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static struct platform_driver ds1wm_driver = {
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.driver = {
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.name = "ds1wm",
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},
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.probe = ds1wm_probe,
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.remove = ds1wm_remove,
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.suspend = ds1wm_suspend,
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.resume = ds1wm_resume
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};
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static int __init ds1wm_init(void)
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{
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printk("DS1WM w1 busmaster driver - (c) 2004 Szabolcs Gyurko\n");
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return platform_driver_register(&ds1wm_driver);
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}
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static void __exit ds1wm_exit(void)
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{
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platform_driver_unregister(&ds1wm_driver);
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}
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module_init(ds1wm_init);
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module_exit(ds1wm_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
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"Matt Reimer <mreimer@vpop.net>");
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MODULE_DESCRIPTION("DS1WM w1 busmaster driver");
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