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minix/drivers/i2c/arch/earm/omap_i2c.c
Thomas Cort cb5e2921b3 i2c: increase read/write timeout 
The sht21 temperature and humidity sensor holds the i2c bus while
an ADC conversion is in progress. For example, a temperature
measurement is requested, a read operation is started, and the
sht21 doesn't respond to the read request until the result of
the measurement is ready. The conversion time isn't constant.
On rare occations (one in hundreds of samples) the timeout in the
i2c driver expires returning an error.

The example code from Sensirion, the sht21's manufacturer, suggests
a bus timeout of 1 second to accommodate the sht21. This commit
increases the bus timeout to 1 second. The timeout is only reached
when chips do not respond normally, so the change doesn't affect the
performance of any other drivers.

Change-Id: I57b0f958a5d0b69b221af380b771fe67401ff604
2013-09-18 08:10:26 -04:00

874 lines
23 KiB
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/*
* This file implements support for i2c on the BeagleBone and BeagleBoard-xM
*/
/* kernel headers */
#include <minix/chardriver.h>
#include <minix/clkconf.h>
#include <minix/drivers.h>
#include <minix/ds.h>
#include <minix/log.h>
#include <minix/mmio.h>
#include <minix/padconf.h>
#include <minix/sysutil.h>
#include <minix/type.h>
#include <minix/spin.h>
/* device headers */
#include <minix/i2c.h>
/* system headers */
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/types.h>
/* usr headers */
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
/* local headers */
#include "omap_i2c.h"
/*
* defines the set of register
*
* Warning: always use the 16-bit variants of read/write/set from mmio.h
* to access these registers. The DM37XX TRM Section 17.6 warns that 32-bit
* accesses can corrupt the register contents.
*/
typedef struct omap_i2c_registers
{
vir_bytes I2C_REVNB_LO; /* AM335X Only */
vir_bytes I2C_REVNB_HI; /* AM335X Only */
vir_bytes I2C_REV; /* DM37XX Only */
vir_bytes I2C_IE; /* DM37XX Only */
vir_bytes I2C_STAT; /* DM37XX Only */
vir_bytes I2C_SYSC;
vir_bytes I2C_IRQSTATUS_RAW; /* AM335X Only */
vir_bytes I2C_IRQSTATUS; /* AM335X Only */
vir_bytes I2C_IRQENABLE_SET; /* AM335X Only */
vir_bytes I2C_IRQENABLE_CLR; /* AM335X Only */
vir_bytes I2C_WE;
vir_bytes I2C_DMARXENABLE_SET; /* AM335X Only */
vir_bytes I2C_DMATXENABLE_SET; /* AM335X Only */
vir_bytes I2C_DMARXENABLE_CLR; /* AM335X Only */
vir_bytes I2C_DMATXENABLE_CLR; /* AM335X Only */
vir_bytes I2C_DMARXWAKE_EN; /* AM335X Only */
vir_bytes I2C_DMATXWAKE_EN; /* AM335X Only */
vir_bytes I2C_SYSS;
vir_bytes I2C_BUF;
vir_bytes I2C_CNT;
vir_bytes I2C_DATA;
vir_bytes I2C_CON;
vir_bytes I2C_OA; /* AM335X Only */
vir_bytes I2C_OA0; /* DM37XX Only */
vir_bytes I2C_SA;
vir_bytes I2C_PSC;
vir_bytes I2C_SCLL;
vir_bytes I2C_SCLH;
vir_bytes I2C_SYSTEST;
vir_bytes I2C_BUFSTAT;
vir_bytes I2C_OA1;
vir_bytes I2C_OA2;
vir_bytes I2C_OA3;
vir_bytes I2C_ACTOA;
vir_bytes I2C_SBLOCK;
} omap_i2c_regs_t;
/* generic definition an i2c bus */
typedef struct omap_i2c_bus
{
enum bus_types
{ AM335X_I2C_BUS, DM37XX_I2C_BUS} bus_type;
phys_bytes mr_base;
phys_bytes mr_size;
vir_bytes mapped_addr;
omap_i2c_regs_t *regs;
uint32_t functional_clock;
uint32_t module_clock;
uint32_t bus_speed;
uint16_t major;
uint16_t minor;
int irq;
int irq_hook_id;
int irq_hook_kernel_id;
} omap_i2c_bus_t;
/* Define the registers for each chip */
static omap_i2c_regs_t am335x_i2c_regs = {
.I2C_REVNB_LO = AM335X_I2C_REVNB_LO,
.I2C_REVNB_HI = AM335X_I2C_REVNB_HI,
.I2C_SYSC = AM335X_I2C_SYSC,
.I2C_IRQSTATUS_RAW = AM335X_I2C_IRQSTATUS_RAW,
.I2C_IRQSTATUS = AM335X_I2C_IRQSTATUS,
.I2C_IRQENABLE_SET = AM335X_I2C_IRQENABLE_SET,
.I2C_IRQENABLE_CLR = AM335X_I2C_IRQENABLE_CLR,
.I2C_WE = AM335X_I2C_WE,
.I2C_DMARXENABLE_SET = AM335X_I2C_DMARXENABLE_SET,
.I2C_DMATXENABLE_SET = AM335X_I2C_DMATXENABLE_SET,
.I2C_DMARXENABLE_CLR = AM335X_I2C_DMARXENABLE_CLR,
.I2C_DMATXENABLE_CLR = AM335X_I2C_DMATXENABLE_CLR,
.I2C_DMARXWAKE_EN = AM335X_I2C_DMARXWAKE_EN,
.I2C_DMATXWAKE_EN = AM335X_I2C_DMATXWAKE_EN,
.I2C_SYSS = AM335X_I2C_SYSS,
.I2C_BUF = AM335X_I2C_BUF,
.I2C_CNT = AM335X_I2C_CNT,
.I2C_DATA = AM335X_I2C_DATA,
.I2C_CON = AM335X_I2C_CON,
.I2C_OA = AM335X_I2C_OA,
.I2C_SA = AM335X_I2C_SA,
.I2C_PSC = AM335X_I2C_PSC,
.I2C_SCLL = AM335X_I2C_SCLL,
.I2C_SCLH = AM335X_I2C_SCLH,
.I2C_SYSTEST = AM335X_I2C_SYSTEST,
.I2C_BUFSTAT = AM335X_I2C_BUFSTAT,
.I2C_OA1 = AM335X_I2C_OA1,
.I2C_OA2 = AM335X_I2C_OA2,
.I2C_OA3 = AM335X_I2C_OA3,
.I2C_ACTOA = AM335X_I2C_ACTOA,
.I2C_SBLOCK = AM335X_I2C_SBLOCK
};
static omap_i2c_regs_t dm37xx_i2c_regs = {
.I2C_REV = DM37XX_I2C_REV,
.I2C_IE = DM37XX_I2C_IE,
.I2C_STAT = DM37XX_I2C_STAT,
.I2C_WE = DM37XX_I2C_WE,
.I2C_SYSS = DM37XX_I2C_SYSS,
.I2C_BUF = DM37XX_I2C_BUF,
.I2C_CNT = DM37XX_I2C_CNT,
.I2C_DATA = DM37XX_I2C_DATA,
.I2C_SYSC = DM37XX_I2C_SYSC,
.I2C_CON = DM37XX_I2C_CON,
.I2C_OA0 = DM37XX_I2C_OA0,
.I2C_SA = DM37XX_I2C_SA,
.I2C_PSC = DM37XX_I2C_PSC,
.I2C_SCLL = DM37XX_I2C_SCLL,
.I2C_SCLH = DM37XX_I2C_SCLH,
.I2C_SYSTEST = DM37XX_I2C_SYSTEST,
.I2C_BUFSTAT = DM37XX_I2C_BUFSTAT,
.I2C_OA1 = DM37XX_I2C_OA1,
.I2C_OA2 = DM37XX_I2C_OA2,
.I2C_OA3 = DM37XX_I2C_OA3,
.I2C_ACTOA = DM37XX_I2C_ACTOA,
.I2C_SBLOCK = DM37XX_I2C_SBLOCK
};
/* Define the buses available on each chip */
static omap_i2c_bus_t am335x_i2c_buses[] = {
{AM335X_I2C_BUS, AM335X_I2C0_BASE, AM335X_I2C0_SIZE, 0, &am335x_i2c_regs,
AM335X_FUNCTIONAL_CLOCK, AM335X_MODULE_CLOCK,
BUS_SPEED_400KHz, AM335X_REV_MAJOR, AM335X_REV_MINOR,
AM335X_I2C0_IRQ, 1, 1},
{AM335X_I2C_BUS, AM335X_I2C1_BASE, AM335X_I2C1_SIZE, 0, &am335x_i2c_regs,
AM335X_FUNCTIONAL_CLOCK, AM335X_MODULE_CLOCK,
BUS_SPEED_100KHz, AM335X_REV_MAJOR, AM335X_REV_MINOR,
AM335X_I2C1_IRQ, 2, 3},
{AM335X_I2C_BUS, AM335X_I2C2_BASE, AM335X_I2C2_SIZE, 0, &am335x_i2c_regs,
AM335X_FUNCTIONAL_CLOCK, AM335X_MODULE_CLOCK,
BUS_SPEED_100KHz, AM335X_REV_MAJOR, AM335X_REV_MINOR,
AM335X_I2C2_IRQ, 3, 3}
};
#define AM335X_OMAP_NBUSES (sizeof(am335x_i2c_buses) / sizeof(omap_i2c_bus_t))
static omap_i2c_bus_t dm37xx_i2c_buses[] = {
{DM37XX_I2C_BUS, DM37XX_I2C0_BASE, DM37XX_I2C0_SIZE, 0, &dm37xx_i2c_regs,
DM37XX_FUNCTIONAL_CLOCK, DM37XX_MODULE_CLOCK,
BUS_SPEED_100KHz, DM37XX_REV_MAJOR, DM37XX_REV_MINOR,
DM37XX_I2C0_IRQ, 1, 1},
{DM37XX_I2C_BUS, DM37XX_I2C1_BASE, DM37XX_I2C1_SIZE, 0, &dm37xx_i2c_regs,
DM37XX_FUNCTIONAL_CLOCK, DM37XX_MODULE_CLOCK,
BUS_SPEED_100KHz, DM37XX_REV_MAJOR, DM37XX_REV_MINOR,
DM37XX_I2C1_IRQ, 2, 2},
{DM37XX_I2C_BUS, DM37XX_I2C2_BASE, DM37XX_I2C2_SIZE, 0, &dm37xx_i2c_regs,
DM37XX_FUNCTIONAL_CLOCK, DM37XX_MODULE_CLOCK,
BUS_SPEED_100KHz, DM37XX_REV_MAJOR, DM37XX_REV_MINOR,
DM37XX_I2C2_IRQ, 3, 3}
};
#define DM37XX_OMAP_NBUSES (sizeof(dm37xx_i2c_buses) / sizeof(omap_i2c_bus_t))
/* Globals */
static omap_i2c_bus_t *omap_i2c_buses; /* all available buses for this SoC */
static omap_i2c_bus_t *omap_i2c_bus; /* the bus selected at start-up */
static int omap_i2c_nbuses; /* number of buses supported by SoC */
/* logging - use with log_warn(), log_info(), log_debug(), log_trace() */
static struct log log = {
.name = "i2c",
.log_level = LEVEL_INFO,
.log_func = default_log
};
/* Local Function Prototypes */
/* Implementation of Generic I2C Interface using Bus Specific Code */
static int omap_i2c_process(minix_i2c_ioctl_exec_t * m);
/* Bus Specific Code */
static void omap_i2c_flush(void);
static uint16_t omap_i2c_poll(uint16_t mask);
static int omap_i2c_bus_is_free(void);
static int omap_i2c_soft_reset(void);
static void omap_i2c_bus_init(void);
static void omap_i2c_padconf(int i2c_bus_id);
static void omap_i2c_clkconf(int i2c_bus_id);
static void omap_i2c_intr_enable(void);
static uint16_t omap_i2c_read_status(void);
static void omap_i2c_write_status(uint16_t mask);
static int omap_i2c_read(i2c_addr_t addr, uint8_t * buf, size_t buflen,
int dostop);
static int omap_i2c_write(i2c_addr_t addr, const uint8_t * buf, size_t buflen,
int dostop);
/*
* Performs the action in minix_i2c_ioctl_exec_t.
*/
static int
omap_i2c_process(minix_i2c_ioctl_exec_t * ioctl_exec)
{
int r;
/*
* Zero data bytes transfers are not allowed. The controller treats
* I2C_CNT register value of 0x0 as 65536. This is true for both the
* am335x and dm37xx. Full details in the TRM on the I2C_CNT page.
*/
if (ioctl_exec->iie_buflen == 0) {
return EINVAL;
}
omap_i2c_flush(); /* clear any garbage in the fifo */
/* Check bus busy flag before using the bus */
r = omap_i2c_bus_is_free();
if (r == 0) {
log_warn(&log, "Bus is busy\n");
return EBUSY;
}
if (ioctl_exec->iie_cmdlen > 0) {
r = omap_i2c_write(ioctl_exec->iie_addr, ioctl_exec->iie_cmd,
ioctl_exec->iie_cmdlen,
!(I2C_OP_READ_P(ioctl_exec->iie_op)));
if (r != OK) {
omap_i2c_soft_reset();
omap_i2c_bus_init();
return r;
}
}
if (I2C_OP_READ_P(ioctl_exec->iie_op)) {
r = omap_i2c_read(ioctl_exec->iie_addr, ioctl_exec->iie_buf,
ioctl_exec->iie_buflen, I2C_OP_STOP_P(ioctl_exec->iie_op));
} else {
r = omap_i2c_write(ioctl_exec->iie_addr, ioctl_exec->iie_buf,
ioctl_exec->iie_buflen, I2C_OP_STOP_P(ioctl_exec->iie_op));
}
if (r != OK) {
omap_i2c_soft_reset();
omap_i2c_bus_init();
return r;
}
return OK;
}
/*
* Drain the incoming FIFO.
*
* Usually called to clear any garbage that may be in the buffer before
* doing a read.
*/
static void
omap_i2c_flush(void)
{
int tries;
int status;
for (tries = 0; tries < 1000; tries++) {
status = omap_i2c_poll(1 << RRDY);
if ((status & (1 << RRDY)) != 0) { /* bytes available for reading */
/* consume the byte and throw it away */
(void) read16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_DATA);
/* clear the read ready flag */
omap_i2c_write_status(1 << RRDY);
} else {
break; /* buffer drained */
}
}
}
/*
* Poll the status register checking the bits set in 'mask'.
* Returns the status if any bits set or 0x0000 when the timeout is reached.
*/
static uint16_t
omap_i2c_poll(uint16_t mask)
{
spin_t spin;
uint16_t status;
/* poll for up to 1 s */
spin_init(&spin, 1000000);
do {
status = omap_i2c_read_status();
if ((status & mask) != 0) { /* any bits in mask set */
return status;
}
} while (spin_check(&spin));
return status; /* timeout reached, abort */
}
/*
* Poll Bus Busy Flag until the bus becomes free (return 1) or the timeout
* expires (return 0).
*/
static int
omap_i2c_bus_is_free(void)
{
spin_t spin;
uint16_t status;
/* wait for up to 1 second for the bus to become free */
spin_init(&spin, 1000000);
do {
status = omap_i2c_read_status();
if ((status & (1 << BB)) == 0) {
return 1; /* bus is free */
}
} while (spin_check(&spin));
return 0; /* timeout expired */
}
static void
omap_i2c_clkconf(int i2c_bus_id)
{
clkconf_init();
if (omap_i2c_bus->bus_type == DM37XX_I2C_BUS) {
clkconf_set(CM_ICLKEN1_CORE, BIT((15 + i2c_bus_id)),
0xffffffff);
clkconf_set(CM_FCLKEN1_CORE, BIT((15 + i2c_bus_id)),
0xffffffff);
} else if (omap_i2c_bus->bus_type == AM335X_I2C_BUS) {
switch (i2c_bus_id) {
case 0:
clkconf_set(CM_WKUP_I2C0_CLKCTRL, BIT(1), 0xffffffff);
break;
case 1:
clkconf_set(CM_PER_I2C1_CLKCTRL, BIT(1), 0xffffffff);
break;
case 2:
clkconf_set(CM_PER_I2C2_CLKCTRL, BIT(1), 0xffffffff);
break;
default:
log_warn(&log, "Invalid i2c_bus_id\n");
break;
}
}
clkconf_release();
}
static void
omap_i2c_padconf(int i2c_bus_id)
{
int r;
u32_t pinopts;
if (omap_i2c_bus->bus_type == AM335X_I2C_BUS) {
/* use the options suggested in starterware driver */
pinopts =
CONTROL_CONF_SLEWCTRL | CONTROL_CONF_RXACTIVE |
CONTROL_CONF_PUTYPESEL;
switch (i2c_bus_id) {
case 0:
pinopts |= CONTROL_CONF_MUXMODE(0);
r = sys_padconf(CONTROL_CONF_I2C0_SDA, 0xffffffff,
pinopts);
if (r != OK) {
log_warn(&log, "padconf failed (r=%d)\n", r);
}
r = sys_padconf(CONTROL_CONF_I2C0_SCL, 0xffffffff,
pinopts);
if (r != OK) {
log_warn(&log, "padconf failed (r=%d)\n", r);
}
log_debug(&log, "pinopts=0x%x\n", pinopts);
break;
case 1:
pinopts |= CONTROL_CONF_MUXMODE(2);
r = sys_padconf(CONTROL_CONF_SPI0_CS0, 0xffffffff,
pinopts);
if (r != OK) {
log_warn(&log, "padconf failed (r=%d)\n", r);
}
r = sys_padconf(CONTROL_CONF_SPI0_D1, 0xffffffff,
pinopts);
if (r != OK) {
log_warn(&log, "padconf failed (r=%d)\n", r);
}
log_debug(&log, "pinopts=0x%x\n", pinopts);
break;
case 2:
pinopts |= CONTROL_CONF_MUXMODE(3);
r = sys_padconf(CONTROL_CONF_UART1_CTSN, 0xffffffff,
pinopts);
if (r != OK) {
log_warn(&log, "padconf failed (r=%d)\n", r);
}
r = sys_padconf(CONTROL_CONF_UART1_RTSN,
0xffffffff, pinopts);
if (r != OK) {
log_warn(&log, "padconf failed (r=%d)\n", r);
}
log_debug(&log, "pinopts=0x%x\n", pinopts);
break;
default:
log_warn(&log, "Invalid i2c_bus_id\n");
break;
}
}
/* nothing to do for the DM37XX */
}
static int
omap_i2c_soft_reset(void)
{
spin_t spin;
/* Disable to do soft reset */
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_CON, 0);
micro_delay(50000);
/* Do a soft reset */
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_SYSC, (1 << SRST));
/* Have to temporarily enable I2C to read RDONE */
set16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_CON, (1<<I2C_EN), (1<<I2C_EN));
micro_delay(50000);
/* wait up to 3 seconds for reset to complete */
spin_init(&spin, 3000000);
do {
if (read16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_SYSS) & (1 << RDONE)) {
return OK;
}
} while (spin_check(&spin));
log_warn(&log, "Tried soft reset, but bus never came back.\n");
return EIO;
}
static void
omap_i2c_intr_enable(void)
{
int r;
uint16_t intmask;
static int policy_set = 0;
static int enabled = 0;
if (!policy_set) {
r = sys_irqsetpolicy(omap_i2c_bus->irq, 0,
&omap_i2c_bus->irq_hook_kernel_id);
if (r == OK) {
policy_set = 1;
} else {
log_warn(&log, "Couldn't set irq policy\n");
}
}
if (policy_set && !enabled) {
r = sys_irqenable(&omap_i2c_bus->irq_hook_kernel_id);
if (r == OK) {
enabled = 1;
} else {
log_warn(&log, "Couldn't enable irq %d (hooked)\n",
omap_i2c_bus->irq);
}
}
/* According to NetBSD driver and u-boot, these are needed even
* if just using polling (i.e. non-interrupt driver programming).
*/
intmask = 0;
intmask |= (1 << ROVR);
intmask |= (1 << AERR);
intmask |= (1 << XRDY);
intmask |= (1 << RRDY);
intmask |= (1 << ARDY);
intmask |= (1 << NACK);
intmask |= (1 << AL);
if (omap_i2c_bus->bus_type == AM335X_I2C_BUS) {
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_IRQENABLE_SET, intmask);
} else if (omap_i2c_bus->bus_type == DM37XX_I2C_BUS) {
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_IE, intmask);
} else {
log_warn(&log, "Don't know how to enable interrupts.\n");
}
}
static void
omap_i2c_bus_init(void)
{
/* Ensure i2c module is disabled before setting prescalar & bus speed */
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_CON, 0);
micro_delay(50000);
/* Disable autoidle */
set16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_SYSC, (1<<AUTOIDLE), (0<<AUTOIDLE));
/* Set prescalar to obtain 12 MHz i2c module clock */
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_PSC,
((omap_i2c_bus->functional_clock / omap_i2c_bus->module_clock) -
1));
/* Set the bus speed */
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_SCLL,
((omap_i2c_bus->module_clock / (2 * omap_i2c_bus->bus_speed)) -
7));
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_SCLH,
((omap_i2c_bus->module_clock / (2 * omap_i2c_bus->bus_speed)) -
5));
/* Set own I2C address */
if (omap_i2c_bus->bus_type == AM335X_I2C_BUS) {
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_OA, I2C_OWN_ADDRESS);
} else if (omap_i2c_bus->bus_type == DM37XX_I2C_BUS) {
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_OA0, I2C_OWN_ADDRESS);
} else {
log_warn(&log, "Don't know how to set own address.\n");
}
/* Set TX/RX Threshold to 1 and disable I2C DMA */
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_BUF, 0x0000);
/* Bring the i2c module out of reset */
set16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_CON, (1<<I2C_EN), (1<<I2C_EN));
micro_delay(50000);
/*
* Enable interrupts
*/
omap_i2c_intr_enable();
}
static uint16_t
omap_i2c_read_status(void)
{
uint16_t status = 0x0000;
if (omap_i2c_bus->bus_type == AM335X_I2C_BUS) {
/* TRM says to use RAW for polling for events */
status = read16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_IRQSTATUS_RAW);
} else if (omap_i2c_bus->bus_type == DM37XX_I2C_BUS) {
status = read16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_STAT);
} else {
log_warn(&log, "Don't know how to read i2c bus status.\n");
}
return status;
}
static void
omap_i2c_write_status(uint16_t mask)
{
if (omap_i2c_bus->bus_type == AM335X_I2C_BUS) {
/* write 1's to IRQSTATUS (not RAW) to clear the bits */
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_IRQSTATUS, mask);
} else if (omap_i2c_bus->bus_type == DM37XX_I2C_BUS) {
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_STAT, mask);
} else {
log_warn(&log, "Don't know how to clear i2c bus status.\n");
}
}
static int
omap_i2c_read(i2c_addr_t addr, uint8_t * buf, size_t buflen, int dostop)
{
int r, i;
uint16_t conopts;
uint16_t pollmask;
uint16_t errmask;
/* Set address of slave device */
conopts = 0;
addr &= MAX_I2C_SA_MASK; /* sanitize address (10-bit max) */
if (addr > 0x7f) {
/* 10-bit extended address in use, need to set XSA */
conopts |= (1 << XSA);
}
errmask = 0;
errmask |= (1 << ROVR);
errmask |= (1 << AERR);
errmask |= (1 << NACK);
errmask |= (1 << AL);
pollmask = 0;
pollmask |= (1 << RRDY);
/* Set bytes to read and slave address */
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_CNT, buflen);
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_SA, addr);
/* Set control register */
conopts |= (1 << I2C_EN); /* enabled */
conopts |= (1 << MST); /* master mode */
conopts |= (1 << STT); /* start condition */
if (dostop != 0) {
conopts |= (1 << STP); /* stop condition */
}
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_CON, conopts);
for (i = 0; i < buflen; i++) {
/* Data to read? */
r = omap_i2c_poll(pollmask | errmask);
if ((r & errmask) != 0) {
/* only debug log level because i2cscan trigers this */
log_debug(&log, "Read Error! Status=%x\n", r);
return EIO;
} else if ((r & pollmask) == 0) {
log_warn(&log, "No RRDY Interrupt. Status=%x\n", r);
log_warn(&log,
"Likely cause: bad pinmux or no devices on bus\n");
return EBUSY;
}
/* read a byte */
buf[i] = read16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_DATA) & 0xff;
/* clear the read ready flag */
omap_i2c_write_status(pollmask);
}
r = omap_i2c_read_status();
if ((r & (1 << NACK)) != 0) {
log_warn(&log, "NACK\n");
return EIO;
}
/* Wait for operation to complete */
pollmask = (1<<ARDY); /* poll access ready bit */
r = omap_i2c_poll(pollmask);
if ((r & pollmask) == 0) {
log_warn(&log, "Read operation never finished.\n");
return EBUSY;
}
omap_i2c_write_status(0x7fff);
return 0;
}
static int
omap_i2c_write(i2c_addr_t addr, const uint8_t * buf, size_t buflen, int dostop)
{
int r, i;
uint16_t conopts;
uint16_t pollmask;
uint16_t errmask;
/* Set address of slave device */
conopts = 0;
addr &= MAX_I2C_SA_MASK; /* sanitize address (10-bit max) */
if (addr > 0x7f) {
/* 10-bit extended address in use, need to set XSA */
conopts |= (1 << XSA);
}
pollmask = 0;
pollmask |= (1 << XRDY);
errmask = 0;
errmask |= (1 << ROVR);
errmask |= (1 << AERR);
errmask |= (1 << NACK);
errmask |= (1 << AL);
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_CNT, buflen);
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_SA, addr);
/* Set control register */
conopts |= (1 << I2C_EN); /* enabled */
conopts |= (1 << MST); /* master mode */
conopts |= (1 << TRX); /* TRX mode */
conopts |= (1 << STT); /* start condition */
if (dostop != 0) {
conopts |= (1 << STP); /* stop condition */
}
omap_i2c_write_status(0x7fff);
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_CON, conopts);
for (i = 0; i < buflen; i++) {
/* Ready to write? */
r = omap_i2c_poll(pollmask | errmask);
if ((r & errmask) != 0) {
log_warn(&log, "Write Error! Status=%x\n", r);
return EIO;
} else if ((r & pollmask) == 0) {
log_warn(&log, "Not ready for write? Status=%x\n", r);
return EBUSY;
}
write16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_DATA, buf[i]);
/* clear the write ready flag */
omap_i2c_write_status(pollmask);
}
r = omap_i2c_read_status();
if ((r & (1 << NACK)) != 0) {
log_warn(&log, "NACK\n");
return EIO;
}
/* Wait for operation to complete */
pollmask = (1<<ARDY); /* poll access ready bit */
r = omap_i2c_poll(pollmask);
if ((r & pollmask) == 0) {
log_warn(&log, "Write operation never finished.\n");
return EBUSY;
}
omap_i2c_write_status(0x7fff);
return 0;
}
int
omap_interface_setup(int (**process) (minix_i2c_ioctl_exec_t * ioctl_exec),
int i2c_bus_id)
{
int r;
int i2c_rev, major, minor;
struct minix_mem_range mr;
/* Fill in the function pointer */
*process = omap_i2c_process;
/* Select the correct i2c definition for this SoC */
#if defined(AM335X)
omap_i2c_buses = am335x_i2c_buses;
omap_i2c_nbuses = AM335X_OMAP_NBUSES;
#elif defined(DM37XX)
omap_i2c_buses = dm37xx_i2c_buses;
omap_i2c_nbuses = DM37XX_OMAP_NBUSES;
#else
#error /* Unsupported SoC */
#endif
if (i2c_bus_id < 0 || i2c_bus_id >= omap_i2c_nbuses) {
return EINVAL;
}
/* select the bus to operate on */
omap_i2c_bus = &omap_i2c_buses[i2c_bus_id];
/* Configure Pins */
omap_i2c_padconf(i2c_bus_id);
/*
* Map I2C Registers
*/
/* Configure memory access */
mr.mr_base = omap_i2c_bus->mr_base; /* start addr */
mr.mr_limit = mr.mr_base + omap_i2c_bus->mr_size; /* end addr */
/* ask for privileges to access the I2C memory range */
if (sys_privctl(SELF, SYS_PRIV_ADD_MEM, &mr) != OK) {
panic("Unable to obtain i2c memory range privileges");
}
/* map the memory into this process */
omap_i2c_bus->mapped_addr = (vir_bytes) vm_map_phys(SELF,
(void *) omap_i2c_bus->mr_base, omap_i2c_bus->mr_size);
if (omap_i2c_bus->mapped_addr == (vir_bytes) MAP_FAILED) {
panic("Unable to map i2c registers");
}
/* Enable Clocks */
omap_i2c_clkconf(i2c_bus_id);
/* Perform a soft reset of the I2C module to ensure a fresh start */
r = omap_i2c_soft_reset();
if (r != OK) {
/* module didn't come back up :( */
return r;
}
/* Bring up I2C module */
omap_i2c_bus_init();
/* Get I2C Revision */
if (omap_i2c_bus->bus_type == AM335X_I2C_BUS) {
/* I2C_REVLO revision: major (bits 10-8), minor (bits 5-0) */
i2c_rev = read16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_REVNB_LO);
major = (i2c_rev >> 8) & 0x07;
minor = i2c_rev & 0x3f;
} else if (omap_i2c_bus->bus_type == DM37XX_I2C_BUS) {
/* I2C_REV revision: major (bits 7-4), minor (bits 3-0) */
i2c_rev = read16(omap_i2c_bus->mapped_addr + omap_i2c_bus->regs->I2C_REV);
major = (i2c_rev >> 4) & 0x0f;
minor = i2c_rev & 0x0f;
} else {
panic("Don't know how to read i2c revision.");
}
if (major != omap_i2c_bus->major || minor != omap_i2c_bus->minor) {
log_warn(&log, "Unrecognized value in I2C_REV register.\n");
log_warn(&log, "Read: 0x%x.0x%x | Expected: 0x%x.0x%x\n",
major, minor, omap_i2c_bus->major, omap_i2c_bus->minor);
}
/* display i2c revision information for debugging purposes */
log_debug(&log, "i2c_%d: I2C rev 0x%x.0x%x\n", (i2c_bus_id + 1),
major, minor);
return OK;
}
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