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Use sam_pio_forceclk() so that we can read the current state of an open-drain output in the TWI reset logic.

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This commit is contained in:
Gregory Nutt 2014-07-09 11:31:21 -06:00
parent c4b9eaa01f
commit ee351dc695
1 changed files with 71 additions and 37 deletions
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108
arch/arm/src/sama5/sam_twi.c
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@ -69,6 +69,7 @@
#include "sam_periphclks.h"
#include "sam_pio.h"
#include "sam_twi.h"
#include "sam_pmc.h" // REMOVE ME
#if defined(CONFIG_SAMA5_TWI0) || defined(CONFIG_SAMA5_TWI1) || \
defined(CONFIG_SAMA5_TWI2) || defined(CONFIG_SAMA5_TWI3)
@ -1146,11 +1147,38 @@ static int twi_transfer(FAR struct i2c_dev_s *dev,
* Initialization
*******************************************************************************/
/****************************************************************************
* Name: twi_enableclk
*
* Description:
* Enable clocking on the selected TWI
*
****************************************************************************/
static void twi_enableclk(struct twi_dev_s *priv)
{
int pid;
/* Get the peripheral ID associated with the TWI device port and enable
* clocking to the TWI block.
*/
pid = priv->attr->pid;
if (pid < 32)
{
sam_enableperiph0(pid);
}
else
{
sam_enableperiph1(pid);
}
}
/*******************************************************************************
* Name: twi_hw_setfrequency
*
* Description:
* Set the frequence for the next transfer
* Set the frequency for the next transfer
*
*******************************************************************************/
@ -1214,6 +1242,10 @@ static void twi_hw_initialize(struct twi_dev_s *priv, uint32_t frequency)
i2cvdbg("TWI%d Initializing\n", priv->attr->twi);
/* Enable peripheral clocking */
twi_enableclk(priv);
/* SVEN: TWI Slave Mode Enabled */
twi_putrel(priv, SAM_TWI_CR_OFFSET, TWI_CR_SVEN);
@ -1283,7 +1315,9 @@ static void twi_hw_initialize(struct twi_dev_s *priv, uint32_t frequency)
* Name: twi_sw_initialize
*
* Description:
* Initialize/Re-initialize one TWI state structure
* Initialize/Re-initialize one TWI state structure. This logic performs
* only repeatable initialization afte (1) the one-time initialization, and
* (2) after each bus reset.
*
*******************************************************************************/
@ -1296,28 +1330,10 @@ static void twi_initialize(struct twi_dev_s *priv, uint32_t frequency)
sam_configpio(priv->attr->sclcfg);
sam_configpio(priv->attr->sdacfg);
/* Initialize the device structure */
priv->dev.ops = &g_twiops;
priv->address = 0;
priv->flags = 0;
sem_init(&priv->exclsem, 0, 1);
sem_init(&priv->waitsem, 0, 0);
/* Allocate a watchdog timer */
priv->timeout = wd_create();
DEBUGASSERT(priv->timeout != 0);
/* Configure and enable the TWI hardware */
twi_hw_initialize(priv, frequency);
/* Attach Interrupt Handler */
irq_attach(priv->attr->irq, priv->attr->handler);
/* Enable Interrupts */
up_enable_irq(priv->attr->irq);
@ -1351,10 +1367,6 @@ struct i2c_dev_s *up_i2cinitialize(int bus)
priv = &g_twi0;
priv->attr = &g_twi0attr;
/* Enable peripheral clocking */
sam_twi0_enableclk();
/* Select the (initial) TWI frequency */
frequency = CONFIG_SAMA5_TWI0_FREQUENCY;
@ -1369,10 +1381,6 @@ struct i2c_dev_s *up_i2cinitialize(int bus)
priv = &g_twi1;
priv->attr = &g_twi1attr;
/* Enable peripheral clocking */
sam_twi1_enableclk();
/* Select the (initial) TWI frequency */
frequency = CONFIG_SAMA5_TWI1_FREQUENCY;
@ -1387,10 +1395,6 @@ struct i2c_dev_s *up_i2cinitialize(int bus)
priv = &g_twi2;
priv->attr = &g_twi2attr;
/* Enable peripheral clocking */
sam_twi2_enableclk();
/* Select the (initial) TWI frequency */
frequency = CONFIG_SAMA5_TWI2_FREQUENCY;
@ -1405,10 +1409,6 @@ struct i2c_dev_s *up_i2cinitialize(int bus)
priv = &g_twi3;
priv->attr = &g_twi2attr;
/* Enable peripheral clocking */
sam_twi3_enableclk();
/* Select the (initial) TWI frequency */
frequency = CONFIG_SAMA5_TWI3_FREQUENCY;
@ -1420,9 +1420,30 @@ struct i2c_dev_s *up_i2cinitialize(int bus)
return NULL;
}
/* Initialize the TWI peripheral */
/* Perform all one time TWI initialization */
irqstate_t flags = irqsave();
priv->dev.ops = &g_twiops;
priv->address = 0;
priv->flags = 0;
sem_init(&priv->exclsem, 0, 1);
sem_init(&priv->waitsem, 0, 0);
/* Allocate a watchdog timer */
priv->timeout = wd_create();
DEBUGASSERT(priv->timeout != 0);
/* Attach Interrupt Handler */
irq_attach(priv->attr->irq, priv->attr->handler);
/* Now perform repeatable initialization */
twi_initialize(priv, frequency);
irqrestore(flags);
return &priv->dev;
}
@ -1501,6 +1522,14 @@ int up_i2creset(FAR struct i2c_dev_s *dev)
sam_configpio(sclpin);
sam_configpio(sdapin);
/* Peripheral clocking must be enabled in order to read valid data from
* the output pin (clocking is enabled automatically for pins configured
* as inputs).
*/
sam_pio_forceclk(sclpin, true);
sam_pio_forceclk(sdapin, true);
/* Let SDA go high (i.e., floating since this is an open-drain output). */
sam_piowrite(sdapin, true);
@ -1566,6 +1595,11 @@ int up_i2creset(FAR struct i2c_dev_s *dev)
sam_piowrite(sdapin, true);
up_udelay(10);
/* Clocking is no longer forced */
sam_pio_forceclk(sclpin, false);
sam_pio_forceclk(sdapin, false);
/* Re-initialize the port (using the saved frequency) */
twi_initialize(priv, frequency);