forked from mirrors/linux
i2c-pxa: Add polling transfer
Add polling I2C transfer implementation for PXA I2C. This is needed for cases where I2C transactions have to occur at times interrups are disabled. Signed-off-by: Mike Rapoport <mike@compulab.co.il> Acked-by: eric miao <eric.miao@marvell.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Mike Rapoport
Jean Delvare
parent
cea443a81c
commit
b7a3670131
3 changed files with 133 additions and 12 deletions
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@ -24,6 +24,7 @@
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#include <asm/arch/ohci.h>
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#include <asm/arch/pm.h>
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#include <asm/arch/dma.h>
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#include <asm/arch/i2c.h>
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#include "generic.h"
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#include "devices.h"
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@ -423,6 +424,11 @@ struct platform_device pxa27x_device_i2c_power = {
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.num_resources = ARRAY_SIZE(i2c_power_resources),
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};
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void __init pxa_set_i2c_power_info(struct i2c_pxa_platform_data *info)
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{
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pxa27x_device_i2c_power.dev.platform_data = info;
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}
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static struct platform_device *devices[] __initdata = {
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&pxa_device_mci,
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&pxa_device_udc,
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@ -65,6 +65,7 @@ struct pxa_i2c {
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unsigned long iosize;
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int irq;
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int use_pio;
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};
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#define _IBMR(i2c) ((i2c)->reg_base + 0)
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@ -163,6 +164,7 @@ static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname)
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#define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)
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static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
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static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id);
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static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
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{
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@ -554,6 +556,71 @@ static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c)
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writel(icr, _ICR(i2c));
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}
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static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
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{
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/* make timeout the same as for interrupt based functions */
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long timeout = 2 * DEF_TIMEOUT;
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/*
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* Wait for the bus to become free.
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*/
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while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
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udelay(1000);
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show_state(i2c);
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}
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if (timeout <= 0) {
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show_state(i2c);
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dev_err(&i2c->adap.dev,
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"i2c_pxa: timeout waiting for bus free\n");
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return I2C_RETRY;
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}
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/*
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* Set master mode.
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*/
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writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
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return 0;
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}
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static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
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struct i2c_msg *msg, int num)
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{
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unsigned long timeout = 500000; /* 5 seconds */
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int ret = 0;
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ret = i2c_pxa_pio_set_master(i2c);
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if (ret)
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goto out;
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i2c->msg = msg;
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i2c->msg_num = num;
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i2c->msg_idx = 0;
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i2c->msg_ptr = 0;
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i2c->irqlogidx = 0;
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i2c_pxa_start_message(i2c);
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while (timeout-- && i2c->msg_num > 0) {
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i2c_pxa_handler(0, i2c);
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udelay(10);
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}
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i2c_pxa_stop_message(i2c);
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/*
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* We place the return code in i2c->msg_idx.
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*/
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ret = i2c->msg_idx;
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out:
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if (timeout == 0)
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i2c_pxa_scream_blue_murder(i2c, "timeout");
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return ret;
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}
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/*
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* We are protected by the adapter bus mutex.
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*/
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@ -610,6 +677,35 @@ static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
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return ret;
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}
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static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,
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struct i2c_msg msgs[], int num)
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{
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struct pxa_i2c *i2c = adap->algo_data;
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int ret, i;
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/* If the I2C controller is disabled we need to reset it
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(probably due to a suspend/resume destroying state). We do
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this here as we can then avoid worrying about resuming the
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controller before its users. */
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if (!(readl(_ICR(i2c)) & ICR_IUE))
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i2c_pxa_reset(i2c);
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for (i = adap->retries; i >= 0; i--) {
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ret = i2c_pxa_do_pio_xfer(i2c, msgs, num);
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if (ret != I2C_RETRY)
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goto out;
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if (i2c_debug)
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dev_dbg(&adap->dev, "Retrying transmission\n");
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udelay(100);
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}
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i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
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ret = -EREMOTEIO;
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out:
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i2c_pxa_set_slave(i2c, ret);
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return ret;
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}
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/*
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* i2c_pxa_master_complete - complete the message and wake up.
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*/
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@ -621,7 +717,8 @@ static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
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i2c->msg_num = 0;
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if (ret)
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i2c->msg_idx = ret;
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wake_up(&i2c->wait);
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if (!i2c->use_pio)
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wake_up(&i2c->wait);
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}
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static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
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@ -840,6 +937,11 @@ static const struct i2c_algorithm i2c_pxa_algorithm = {
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.functionality = i2c_pxa_functionality,
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};
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static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
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.master_xfer = i2c_pxa_pio_xfer,
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.functionality = i2c_pxa_functionality,
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};
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static void i2c_pxa_enable(struct platform_device *dev)
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{
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if (cpu_is_pxa27x()) {
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@ -890,7 +992,6 @@ static int i2c_pxa_probe(struct platform_device *dev)
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}
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i2c->adap.owner = THIS_MODULE;
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i2c->adap.algo = &i2c_pxa_algorithm;
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i2c->adap.retries = 5;
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spin_lock_init(&i2c->lock);
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@ -927,20 +1028,26 @@ static int i2c_pxa_probe(struct platform_device *dev)
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clk_enable(i2c->clk);
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i2c_pxa_enable(dev);
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ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,
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i2c->adap.name, i2c);
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if (ret)
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goto ereqirq;
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if (plat) {
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i2c->adap.class = plat->class;
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i2c->use_pio = plat->use_pio;
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}
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if (i2c->use_pio) {
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i2c->adap.algo = &i2c_pxa_pio_algorithm;
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} else {
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i2c->adap.algo = &i2c_pxa_algorithm;
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ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,
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i2c->adap.name, i2c);
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if (ret)
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goto ereqirq;
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}
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i2c_pxa_reset(i2c);
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i2c->adap.algo_data = i2c;
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i2c->adap.dev.parent = &dev->dev;
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if (plat) {
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i2c->adap.class = plat->class;
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}
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/*
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* If "dev->id" is negative we consider it as zero.
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* The reason to do so is to avoid sysfs names that only make
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@ -966,7 +1073,8 @@ static int i2c_pxa_probe(struct platform_device *dev)
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return 0;
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eadapt:
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free_irq(irq, i2c);
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if (!i2c->use_pio)
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free_irq(irq, i2c);
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ereqirq:
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clk_disable(i2c->clk);
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i2c_pxa_disable(dev);
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@ -986,7 +1094,8 @@ static int i2c_pxa_remove(struct platform_device *dev)
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platform_set_drvdata(dev, NULL);
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i2c_del_adapter(&i2c->adap);
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free_irq(i2c->irq, i2c);
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if (!i2c->use_pio)
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free_irq(i2c->irq, i2c);
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clk_disable(i2c->clk);
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clk_put(i2c->clk);
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@ -65,7 +65,13 @@ struct i2c_pxa_platform_data {
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unsigned int slave_addr;
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struct i2c_slave_client *slave;
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unsigned int class;
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int use_pio;
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};
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extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);
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#ifdef CONFIG_PXA27x
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extern void pxa_set_i2c_power_info(struct i2c_pxa_platform_data *info);
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#endif
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#endif
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