Adds support for set-speed on the OMAP24xx I2C Adapter.
Changes to omap24_i2c_write(...) for polling ARDY Bit from IRQ-Status. Otherwise on a subsequent call the transfer of last byte from the predecessor is aborted and therefore lost. For exmaple when i2c_write(...) is followed by a i2c_setspeed(...) (which has to deactivate and activate master for changing psc,...).
Minor cosmetical changes.
Signed-off-by: Hannes Petermaier oe5hpm@oevsv.at Cc: Heiko Schocher hs@denx.de --- Changes for v4: - patch v3 had style problems: fixed - handle return value of omap24_i2c_setspeed during init - polling ARDY bit could end up in an endless-loop: fixed Changes for v3: - patch v2 was corrupt at line 114 ?! - more meaningfull text in commit-message Changes for v2: - fixed compile error due to '= =' - removed [PATCH 1/2]: only 1 patch is needed - fixed omap24_i2c_write(...) for waiting until all transfer is finished.
drivers/i2c/omap24xx_i2c.c | 147 +++++++++++++++++++++++++++++--------------- include/i2c.h | 1 + 2 files changed, 98 insertions(+), 50 deletions(-)
diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c index c784004..a39b591 100644 --- a/drivers/i2c/omap24xx_i2c.c +++ b/drivers/i2c/omap24xx_i2c.c @@ -32,6 +32,10 @@ * - Status functions now read irqstatus_raw as per TRM guidelines * (except for OMAP243X and OMAP34XX). * - Driver now supports up to I2C5 (OMAP5). + * + * Copyright (c) 2014 Hannes Petermaier oe5hpm@oevsv.at, B&R + * - Added support for set_speed + * */
#include <common.h> @@ -53,43 +57,66 @@ static int wait_for_bb(struct i2c_adapter *adap); static struct i2c *omap24_get_base(struct i2c_adapter *adap); static u16 wait_for_event(struct i2c_adapter *adap); static void flush_fifo(struct i2c_adapter *adap); - -static void omap24_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd) +static int omap24_i2c_findpsc(u32 *pscl, u32 *psch, uint speed) { - struct i2c *i2c_base = omap24_get_base(adap); - int psc, fsscll, fssclh; - int hsscll = 0, hssclh = 0; - u32 scll, sclh; - int timeout = I2C_TIMEOUT; + unsigned int sampleclk, prescaler; + int fsscll, fssclh;
- /* Only handle standard, fast and high speeds */ - if ((speed != OMAP_I2C_STANDARD) && - (speed != OMAP_I2C_FAST_MODE) && - (speed != OMAP_I2C_HIGH_SPEED)) { - printf("Error : I2C unsupported speed %d\n", speed); - return; - } + speed <<= 1; + prescaler = 0; + /* + * some divisors may cause a precission loss, but shouldn't + * be a big thing, because i2c_clk is then allready very slow. + */ + while (prescaler <= 0xFF) { + sampleclk = I2C_IP_CLK / (prescaler+1);
- psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK; - psc -= 1; - if (psc < I2C_PSC_MIN) { - printf("Error : I2C unsupported prescalar %d\n", psc); - return; + fsscll = sampleclk / speed; + fssclh = fsscll; + fsscll -= I2C_FASTSPEED_SCLL_TRIM; + fssclh -= I2C_FASTSPEED_SCLH_TRIM; + + if (((fsscll > 0) && (fssclh > 0)) && + ((fsscll <= (255-I2C_FASTSPEED_SCLL_TRIM)) && + (fssclh <= (255-I2C_FASTSPEED_SCLH_TRIM)))) { + if (pscl) + *pscl = fsscll; + if (psch) + *psch = fssclh; + + return prescaler; + } + prescaler++; } + return -1; +} +static uint omap24_i2c_setspeed(struct i2c_adapter *adap, uint speed) +{ + struct i2c *i2c_base = omap24_get_base(adap); + int psc, fsscll = 0, fssclh = 0; + int hsscll = 0, hssclh = 0; + u32 scll = 0, sclh = 0;
- if (speed == OMAP_I2C_HIGH_SPEED) { + if (speed >= OMAP_I2C_HIGH_SPEED) { /* High speed */ + psc = I2C_IP_CLK / I2C_INTERNAL_SAMPLING_CLK; + psc -= 1; + if (psc < I2C_PSC_MIN) { + printf("Error : I2C unsupported prescaler %d\n", psc); + return -1; + }
/* For first phase of HS mode */ - fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK / - (2 * OMAP_I2C_FAST_MODE); + fsscll = I2C_INTERNAL_SAMPLING_CLK / (2 * speed); + + fssclh = fsscll;
fsscll -= I2C_HIGHSPEED_PHASE_ONE_SCLL_TRIM; fssclh -= I2C_HIGHSPEED_PHASE_ONE_SCLH_TRIM; if (((fsscll < 0) || (fssclh < 0)) || ((fsscll > 255) || (fssclh > 255))) { puts("Error : I2C initializing first phase clock\n"); - return; + return -1; }
/* For second phase of HS mode */ @@ -100,7 +127,7 @@ static void omap24_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd) if (((fsscll < 0) || (fssclh < 0)) || ((fsscll > 255) || (fssclh > 255))) { puts("Error : I2C initializing second phase clock\n"); - return; + return -1; }
scll = (unsigned int)hsscll << 8 | (unsigned int)fsscll; @@ -108,20 +135,29 @@ static void omap24_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
} else { /* Standard and fast speed */ - fsscll = fssclh = I2C_INTERNAL_SAMPLING_CLK / (2 * speed); - - fsscll -= I2C_FASTSPEED_SCLL_TRIM; - fssclh -= I2C_FASTSPEED_SCLH_TRIM; - if (((fsscll < 0) || (fssclh < 0)) || - ((fsscll > 255) || (fssclh > 255))) { + psc = omap24_i2c_findpsc(&scll, &sclh, speed); + if (0 > psc) { puts("Error : I2C initializing clock\n"); - return; + return -1; } - - scll = (unsigned int)fsscll; - sclh = (unsigned int)fssclh; }
+ adap->speed = speed; + adap->waitdelay = (10000000 / speed) * 2; /* wait for 20 clkperiods */ + writew(0, &i2c_base->con); + writew(psc, &i2c_base->psc); + writew(scll, &i2c_base->scll); + writew(sclh, &i2c_base->sclh); + writew(I2C_CON_EN, &i2c_base->con); + writew(0xFFFF, &i2c_base->stat); /* clear all pending status */ + + return 0; +} +static void omap24_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd) +{ + struct i2c *i2c_base = omap24_get_base(adap); + int timeout = I2C_TIMEOUT; + if (readw(&i2c_base->con) & I2C_CON_EN) { writew(0, &i2c_base->con); udelay(50000); @@ -139,14 +175,14 @@ static void omap24_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd) udelay(1000); }
- writew(0, &i2c_base->con); - writew(psc, &i2c_base->psc); - writew(scll, &i2c_base->scll); - writew(sclh, &i2c_base->sclh); + if (0 != omap24_i2c_setspeed(adap, speed)) { + printf("ERROR: failed to setup I2C bus-speed!\n"); + return; + }
/* own address */ writew(slaveadd, &i2c_base->oa); - writew(I2C_CON_EN, &i2c_base->con); + #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) /* * Have to enable interrupts for OMAP2/3, these IPs don't have @@ -165,7 +201,8 @@ static void flush_fifo(struct i2c_adapter *adap) struct i2c *i2c_base = omap24_get_base(adap); u16 stat;
- /* note: if you try and read data when its not there or ready + /* + * note: if you try and read data when its not there or ready * you get a bus error */ while (1) { @@ -220,8 +257,8 @@ static int omap24_i2c_probe(struct i2c_adapter *adap, uchar chip)
/* Check for ACK (!NAK) */ if (!(status & I2C_STAT_NACK)) { - res = 0; /* Device found */ - udelay(I2C_WAIT); /* Required by AM335X in SPL */ + res = 0; /* Device found */ + udelay(adap->waitdelay);/* Required by AM335X in SPL */ /* Abort transfer (force idle state) */ writew(I2C_CON_MST | I2C_CON_TRX, &i2c_base->con); /* Reset */ udelay(1000); @@ -307,7 +344,7 @@ static int omap24_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr, adap->hwadapnr, status); goto rd_exit; } - if (status == 0 || status & I2C_STAT_NACK) { + if (status == 0 || (status & I2C_STAT_NACK)) { i2c_error = 1; printf("i2c_read: error waiting for addr ACK (status=0x%x)\n", status); @@ -351,7 +388,7 @@ static int omap24_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr, adap->hwadapnr, status); goto rd_exit; } - if (status == 0 || status & I2C_STAT_NACK) { + if (status == 0 || (status & I2C_STAT_NACK)) { i2c_error = 1; goto rd_exit; } @@ -379,6 +416,7 @@ static int omap24_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr, int i; u16 status; int i2c_error = 0; + int timeout = I2C_TIMEOUT;
if (alen < 0) { puts("I2C write: addr len < 0\n"); @@ -428,7 +466,7 @@ static int omap24_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr, adap->hwadapnr, status); goto wr_exit; } - if (status == 0 || status & I2C_STAT_NACK) { + if (status == 0 || (status & I2C_STAT_NACK)) { i2c_error = 1; printf("i2c_write: error waiting for addr ACK (status=0x%x)\n", status); @@ -448,7 +486,7 @@ static int omap24_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr, /* Address phase is over, now write data */ for (i = 0; i < len; i++) { status = wait_for_event(adap); - if (status == 0 || status & I2C_STAT_NACK) { + if (status == 0 || (status & I2C_STAT_NACK)) { i2c_error = 1; printf("i2c_write: error waiting for data ACK (status=0x%x)\n", status); @@ -464,6 +502,15 @@ static int omap24_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr, goto wr_exit; } } + /* + * poll ARDY bit for making sure that last byte really has been + * transferred on the bus. + */ + do { + status = wait_for_event(adap); + } while (!(status & I2C_STAT_ARDY) && timeout--); + if (timeout <= 0) + printf("i2c_write: timed out writig last byte!\n");
wr_exit: flush_fifo(adap); @@ -490,7 +537,7 @@ static int wait_for_bb(struct i2c_adapter *adap) I2C_STAT_BB) && timeout--) { #endif writew(stat, &i2c_base->stat); - udelay(I2C_WAIT); + udelay(adap->waitdelay); }
if (timeout <= 0) { @@ -513,7 +560,7 @@ static u16 wait_for_event(struct i2c_adapter *adap) int timeout = I2C_TIMEOUT;
do { - udelay(I2C_WAIT); + udelay(adap->waitdelay); #if defined(CONFIG_OMAP243X) || defined(CONFIG_OMAP34XX) status = readw(&i2c_base->stat); #else @@ -580,12 +627,12 @@ static struct i2c *omap24_get_base(struct i2c_adapter *adap) #endif
U_BOOT_I2C_ADAP_COMPLETE(omap24_0, omap24_i2c_init, omap24_i2c_probe, - omap24_i2c_read, omap24_i2c_write, NULL, + omap24_i2c_read, omap24_i2c_write, omap24_i2c_setspeed, CONFIG_SYS_OMAP24_I2C_SPEED, CONFIG_SYS_OMAP24_I2C_SLAVE, 0) U_BOOT_I2C_ADAP_COMPLETE(omap24_1, omap24_i2c_init, omap24_i2c_probe, - omap24_i2c_read, omap24_i2c_write, NULL, + omap24_i2c_read, omap24_i2c_write, omap24_i2c_setspeed, CONFIG_SYS_OMAP24_I2C_SPEED1, CONFIG_SYS_OMAP24_I2C_SLAVE1, 1) diff --git a/include/i2c.h b/include/i2c.h index f93a183..1b4078e 100644 --- a/include/i2c.h +++ b/include/i2c.h @@ -68,6 +68,7 @@ struct i2c_adapter { uint (*set_bus_speed)(struct i2c_adapter *adap, uint speed); int speed; + int waitdelay; int slaveaddr; int init_done; int hwadapnr;