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Commit b7a36701 authored by Mike Rapoport's avatar Mike Rapoport Committed by Jean Delvare
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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: default avatarMike Rapoport <mike@compulab.co.il>
Acked-by: default avatareric miao <eric.miao@marvell.com>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent cea443a8

arch/arm/mach-pxa/pxa27x.c

+6 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <asm/arch/ohci.h>

#include <asm/arch/pm.h>

#include <asm/arch/dma.h>

#include <asm/arch/i2c.h>



#include "generic.h"

#include "devices.h"
@@ -423,6 +424,11 @@ struct platform_device pxa27x_device_i2c_power = { 
	.num_resources	= ARRAY_SIZE(i2c_power_resources),

};



void __init pxa_set_i2c_power_info(struct i2c_pxa_platform_data *info)

{

	pxa27x_device_i2c_power.dev.platform_data = info;

}



static struct platform_device *devices[] __initdata = {

	&pxa_device_mci,

	&pxa_device_udc,

drivers/i2c/busses/i2c-pxa.c

+121 −12
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ struct pxa_i2c { 
	unsigned long		iosize;



	int			irq;

	int			use_pio;

};



#define _IBMR(i2c)	((i2c)->reg_base + 0)
@@ -163,6 +164,7 @@ static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname) 
#define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)



static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);

static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id);



static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)

{
@@ -554,6 +556,71 @@ static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c) 
	writel(icr, _ICR(i2c));

}



static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)

{

	/* make timeout the same as for interrupt based functions */

	long timeout = 2 * DEF_TIMEOUT;



	/*

	 * Wait for the bus to become free.

	 */

	while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {

		udelay(1000);

		show_state(i2c);

	}



	if (timeout <= 0) {

		show_state(i2c);

		dev_err(&i2c->adap.dev,

			"i2c_pxa: timeout waiting for bus free\n");

		return I2C_RETRY;

	}



	/*

	 * Set master mode.

	 */

	writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));



	return 0;

}



static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,

			       struct i2c_msg *msg, int num)

{

	unsigned long timeout = 500000; /* 5 seconds */

	int ret = 0;



	ret = i2c_pxa_pio_set_master(i2c);

	if (ret)

		goto out;



	i2c->msg = msg;

	i2c->msg_num = num;

	i2c->msg_idx = 0;

	i2c->msg_ptr = 0;

	i2c->irqlogidx = 0;



	i2c_pxa_start_message(i2c);



	while (timeout-- && i2c->msg_num > 0) {

		i2c_pxa_handler(0, i2c);

		udelay(10);

	}



	i2c_pxa_stop_message(i2c);



	/*

	 * We place the return code in i2c->msg_idx.

	 */

	ret = i2c->msg_idx;



out:

	if (timeout == 0)

		i2c_pxa_scream_blue_murder(i2c, "timeout");



	return ret;

}



/*

 * We are protected by the adapter bus mutex.

 */
@@ -610,6 +677,35 @@ static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num) 
	return ret;

}



static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,

			    struct i2c_msg msgs[], int num)

{

	struct pxa_i2c *i2c = adap->algo_data;

	int ret, i;



	/* If the I2C controller is disabled we need to reset it

	  (probably due to a suspend/resume destroying state). We do

	  this here as we can then avoid worrying about resuming the

	  controller before its users. */

	if (!(readl(_ICR(i2c)) & ICR_IUE))

		i2c_pxa_reset(i2c);



	for (i = adap->retries; i >= 0; i--) {

		ret = i2c_pxa_do_pio_xfer(i2c, msgs, num);

		if (ret != I2C_RETRY)

			goto out;



		if (i2c_debug)

			dev_dbg(&adap->dev, "Retrying transmission\n");

		udelay(100);

	}

	i2c_pxa_scream_blue_murder(i2c, "exhausted retries");

	ret = -EREMOTEIO;

 out:

	i2c_pxa_set_slave(i2c, ret);

	return ret;

}



/*

 * i2c_pxa_master_complete - complete the message and wake up.

 */
@@ -621,6 +717,7 @@ static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret) 
	i2c->msg_num = 0;

	if (ret)

		i2c->msg_idx = ret;

	if (!i2c->use_pio)

		wake_up(&i2c->wait);

}
@@ -840,6 +937,11 @@ static const struct i2c_algorithm i2c_pxa_algorithm = { 
	.functionality	= i2c_pxa_functionality,

};



static const struct i2c_algorithm i2c_pxa_pio_algorithm = {

	.master_xfer	= i2c_pxa_pio_xfer,

	.functionality	= i2c_pxa_functionality,

};



static void i2c_pxa_enable(struct platform_device *dev)

{

	if (cpu_is_pxa27x()) {
@@ -890,7 +992,6 @@ static int i2c_pxa_probe(struct platform_device *dev) 
	}



	i2c->adap.owner   = THIS_MODULE;

	i2c->adap.algo    = &i2c_pxa_algorithm;

	i2c->adap.retries = 5;



	spin_lock_init(&i2c->lock);
@@ -927,20 +1028,26 @@ static int i2c_pxa_probe(struct platform_device *dev) 
	clk_enable(i2c->clk);

	i2c_pxa_enable(dev);



	if (plat) {

		i2c->adap.class = plat->class;

		i2c->use_pio = plat->use_pio;

	}



	if (i2c->use_pio) {

		i2c->adap.algo = &i2c_pxa_pio_algorithm;

	} else {

		i2c->adap.algo = &i2c_pxa_algorithm;

		ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,

				  i2c->adap.name, i2c);

		if (ret)

			goto ereqirq;

	}



	i2c_pxa_reset(i2c);



	i2c->adap.algo_data = i2c;

	i2c->adap.dev.parent = &dev->dev;



	if (plat) {

		i2c->adap.class = plat->class;

	}



	/*

	 * If "dev->id" is negative we consider it as zero.

	 * The reason to do so is to avoid sysfs names that only make
@@ -966,6 +1073,7 @@ static int i2c_pxa_probe(struct platform_device *dev) 
	return 0;



eadapt:

	if (!i2c->use_pio)

		free_irq(irq, i2c);

ereqirq:

	clk_disable(i2c->clk);
@@ -986,6 +1094,7 @@ static int i2c_pxa_remove(struct platform_device *dev) 
	platform_set_drvdata(dev, NULL);



	i2c_del_adapter(&i2c->adap);

	if (!i2c->use_pio)

		free_irq(i2c->irq, i2c);



	clk_disable(i2c->clk);

include/asm-arm/arch-pxa/i2c.h

+6 −0
Original line number Diff line number Diff line
@@ -65,7 +65,13 @@ struct i2c_pxa_platform_data { 
	unsigned int		slave_addr;

	struct i2c_slave_client	*slave;

	unsigned int		class;

	int			use_pio;

};



extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);



#ifdef CONFIG_PXA27x

extern void pxa_set_i2c_power_info(struct i2c_pxa_platform_data *info);

#endif



#endif