diff options
Diffstat (limited to 'u-boot/drivers/i2c/fsl_i2c.c')
| -rw-r--r-- | u-boot/drivers/i2c/fsl_i2c.c | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/u-boot/drivers/i2c/fsl_i2c.c b/u-boot/drivers/i2c/fsl_i2c.c new file mode 100644 index 0000000..cb13dee --- /dev/null +++ b/u-boot/drivers/i2c/fsl_i2c.c @@ -0,0 +1,492 @@ +/* + * Copyright 2006,2009 Freescale Semiconductor, Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * Version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> + +#ifdef CONFIG_HARD_I2C + +#include <command.h> +#include <i2c.h> /* Functional interface */ + +#include <asm/io.h> +#include <asm/fsl_i2c.h> /* HW definitions */ + +/* The maximum number of microseconds we will wait until another master has + * released the bus. If not defined in the board header file, then use a + * generic value. + */ +#ifndef CONFIG_I2C_MBB_TIMEOUT +#define CONFIG_I2C_MBB_TIMEOUT 100000 +#endif + +/* The maximum number of microseconds we will wait for a read or write + * operation to complete. If not defined in the board header file, then use a + * generic value. + */ +#ifndef CONFIG_I2C_TIMEOUT +#define CONFIG_I2C_TIMEOUT 10000 +#endif + +#define I2C_READ_BIT 1 +#define I2C_WRITE_BIT 0 + +DECLARE_GLOBAL_DATA_PTR; + +/* Initialize the bus pointer to whatever one the SPD EEPROM is on. + * Default is bus 0. This is necessary because the DDR initialization + * runs from ROM, and we can't switch buses because we can't modify + * the global variables. + */ +#ifndef CONFIG_SYS_SPD_BUS_NUM +#define CONFIG_SYS_SPD_BUS_NUM 0 +#endif +static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = CONFIG_SYS_SPD_BUS_NUM; +#if defined(CONFIG_I2C_MUX) +static unsigned int i2c_bus_num_mux __attribute__ ((section ("data"))) = 0; +#endif + +static unsigned int i2c_bus_speed[2] = {CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SPEED}; + +static const struct fsl_i2c *i2c_dev[2] = { + (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C_OFFSET), +#ifdef CONFIG_SYS_I2C2_OFFSET + (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C2_OFFSET) +#endif +}; + +/* I2C speed map for a DFSR value of 1 */ + +/* + * Map I2C frequency dividers to FDR and DFSR values + * + * This structure is used to define the elements of a table that maps I2C + * frequency divider (I2C clock rate divided by I2C bus speed) to a value to be + * programmed into the Frequency Divider Ratio (FDR) and Digital Filter + * Sampling Rate (DFSR) registers. + * + * The actual table should be defined in the board file, and it must be called + * fsl_i2c_speed_map[]. + * + * The last entry of the table must have a value of {-1, X}, where X is same + * FDR/DFSR values as the second-to-last entry. This guarantees that any + * search through the array will always find a match. + * + * The values of the divider must be in increasing numerical order, i.e. + * fsl_i2c_speed_map[x+1].divider > fsl_i2c_speed_map[x].divider. + * + * For this table, the values are based on a value of 1 for the DFSR + * register. See the application note AN2919 "Determining the I2C Frequency + * Divider Ratio for SCL" + * + * ColdFire I2C frequency dividers for FDR values are different from + * PowerPC. The protocol to use the I2C module is still the same. + * A different table is defined and are based on MCF5xxx user manual. + * + */ +static const struct { + unsigned short divider; + u8 fdr; +} fsl_i2c_speed_map[] = { +#ifdef __M68K__ + {20, 32}, {22, 33}, {24, 34}, {26, 35}, + {28, 0}, {28, 36}, {30, 1}, {32, 37}, + {34, 2}, {36, 38}, {40, 3}, {40, 39}, + {44, 4}, {48, 5}, {48, 40}, {56, 6}, + {56, 41}, {64, 42}, {68, 7}, {72, 43}, + {80, 8}, {80, 44}, {88, 9}, {96, 41}, + {104, 10}, {112, 42}, {128, 11}, {128, 43}, + {144, 12}, {160, 13}, {160, 48}, {192, 14}, + {192, 49}, {224, 50}, {240, 15}, {256, 51}, + {288, 16}, {320, 17}, {320, 52}, {384, 18}, + {384, 53}, {448, 54}, {480, 19}, {512, 55}, + {576, 20}, {640, 21}, {640, 56}, {768, 22}, + {768, 57}, {960, 23}, {896, 58}, {1024, 59}, + {1152, 24}, {1280, 25}, {1280, 60}, {1536, 26}, + {1536, 61}, {1792, 62}, {1920, 27}, {2048, 63}, + {2304, 28}, {2560, 29}, {3072, 30}, {3840, 31}, + {-1, 31} +#endif +}; + +/** + * Set the I2C bus speed for a given I2C device + * + * @param dev: the I2C device + * @i2c_clk: I2C bus clock frequency + * @speed: the desired speed of the bus + * + * The I2C device must be stopped before calling this function. + * + * The return value is the actual bus speed that is set. + */ +static unsigned int set_i2c_bus_speed(const struct fsl_i2c *dev, + unsigned int i2c_clk, unsigned int speed) +{ + unsigned short divider = min(i2c_clk / speed, (unsigned short) -1); + + /* + * We want to choose an FDR/DFSR that generates an I2C bus speed that + * is equal to or lower than the requested speed. That means that we + * want the first divider that is equal to or greater than the + * calculated divider. + */ +#ifdef __PPC__ + u8 dfsr, fdr = 0x31; /* Default if no FDR found */ + /* a, b and dfsr matches identifiers A,B and C respectively in AN2919 */ + unsigned short a, b, ga, gb; + unsigned long c_div, est_div; + +#ifdef CONFIG_FSL_I2C_CUSTOM_DFSR + dfsr = CONFIG_FSL_I2C_CUSTOM_DFSR; +#else + /* Condition 1: dfsr <= 50/T */ + dfsr = (5 * (i2c_clk / 1000)) / 100000; +#endif +#ifdef CONFIG_FSL_I2C_CUSTOM_FDR + fdr = CONFIG_FSL_I2C_CUSTOM_FDR; + speed = i2c_clk / divider; /* Fake something */ +#else + debug("Requested speed:%d, i2c_clk:%d\n", speed, i2c_clk); + if (!dfsr) + dfsr = 1; + + est_div = ~0; + for (ga = 0x4, a = 10; a <= 30; ga++, a += 2) { + for (gb = 0; gb < 8; gb++) { + b = 16 << gb; + c_div = b * (a + ((3*dfsr)/b)*2); + if ((c_div > divider) && (c_div < est_div)) { + unsigned short bin_gb, bin_ga; + + est_div = c_div; + bin_gb = gb << 2; + bin_ga = (ga & 0x3) | ((ga & 0x4) << 3); + fdr = bin_gb | bin_ga; + speed = i2c_clk / est_div; + debug("FDR:0x%.2x, div:%ld, ga:0x%x, gb:0x%x, " + "a:%d, b:%d, speed:%d\n", + fdr, est_div, ga, gb, a, b, speed); + /* Condition 2 not accounted for */ + debug("Tr <= %d ns\n", + (b - 3 * dfsr) * 1000000 / + (i2c_clk / 1000)); + } + } + if (a == 20) + a += 2; + if (a == 24) + a += 4; + } + debug("divider:%d, est_div:%ld, DFSR:%d\n", divider, est_div, dfsr); + debug("FDR:0x%.2x, speed:%d\n", fdr, speed); +#endif + writeb(dfsr, &dev->dfsrr); /* set default filter */ + writeb(fdr, &dev->fdr); /* set bus speed */ +#else + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(fsl_i2c_speed_map); i++) + if (fsl_i2c_speed_map[i].divider >= divider) { + u8 fdr; + + fdr = fsl_i2c_speed_map[i].fdr; + speed = i2c_clk / fsl_i2c_speed_map[i].divider; + writeb(fdr, &dev->fdr); /* set bus speed */ + + break; + } +#endif + return speed; +} + +void +i2c_init(int speed, int slaveadd) +{ + struct fsl_i2c *dev; + unsigned int temp; + +#ifdef CONFIG_SYS_I2C_INIT_BOARD + /* Call board specific i2c bus reset routine before accessing the + * environment, which might be in a chip on that bus. For details + * about this problem see doc/I2C_Edge_Conditions. + */ + i2c_init_board(); +#endif + dev = (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C_OFFSET); + + writeb(0, &dev->cr); /* stop I2C controller */ + udelay(5); /* let it shutdown in peace */ + temp = set_i2c_bus_speed(dev, gd->i2c1_clk, speed); + if (gd->flags & GD_FLG_RELOC) + i2c_bus_speed[0] = temp; + writeb(slaveadd << 1, &dev->adr); /* write slave address */ + writeb(0x0, &dev->sr); /* clear status register */ + writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */ + +#ifdef CONFIG_SYS_I2C2_OFFSET + dev = (struct fsl_i2c *) (CONFIG_SYS_IMMR + CONFIG_SYS_I2C2_OFFSET); + + writeb(0, &dev->cr); /* stop I2C controller */ + udelay(5); /* let it shutdown in peace */ + temp = set_i2c_bus_speed(dev, gd->i2c2_clk, speed); + if (gd->flags & GD_FLG_RELOC) + i2c_bus_speed[1] = temp; + writeb(slaveadd << 1, &dev->adr); /* write slave address */ + writeb(0x0, &dev->sr); /* clear status register */ + writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */ +#endif + +#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT + /* Call board specific i2c bus reset routine AFTER the bus has been + * initialized. Use either this callpoint or i2c_init_board; + * which is called before i2c_init operations. + * For details about this problem see doc/I2C_Edge_Conditions. + */ + i2c_board_late_init(); +#endif +} + +static int +i2c_wait4bus(void) +{ + unsigned long long timeval = get_ticks(); + const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT); + + while (readb(&i2c_dev[i2c_bus_num]->sr) & I2C_SR_MBB) { + if ((get_ticks() - timeval) > timeout) + return -1; + } + + return 0; +} + +static __inline__ int +i2c_wait(int write) +{ + u32 csr; + unsigned long long timeval = get_ticks(); + const unsigned long long timeout = usec2ticks(CONFIG_I2C_TIMEOUT); + + do { + csr = readb(&i2c_dev[i2c_bus_num]->sr); + if (!(csr & I2C_SR_MIF)) + continue; + /* Read again to allow register to stabilise */ + csr = readb(&i2c_dev[i2c_bus_num]->sr); + + writeb(0x0, &i2c_dev[i2c_bus_num]->sr); + + if (csr & I2C_SR_MAL) { + debug("i2c_wait: MAL\n"); + return -1; + } + + if (!(csr & I2C_SR_MCF)) { + debug("i2c_wait: unfinished\n"); + return -1; + } + + if (write == I2C_WRITE_BIT && (csr & I2C_SR_RXAK)) { + debug("i2c_wait: No RXACK\n"); + return -1; + } + + return 0; + } while ((get_ticks() - timeval) < timeout); + + debug("i2c_wait: timed out\n"); + return -1; +} + +static __inline__ int +i2c_write_addr (u8 dev, u8 dir, int rsta) +{ + writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX + | (rsta ? I2C_CR_RSTA : 0), + &i2c_dev[i2c_bus_num]->cr); + + writeb((dev << 1) | dir, &i2c_dev[i2c_bus_num]->dr); + + if (i2c_wait(I2C_WRITE_BIT) < 0) + return 0; + + return 1; +} + +static __inline__ int +__i2c_write(u8 *data, int length) +{ + int i; + + for (i = 0; i < length; i++) { + writeb(data[i], &i2c_dev[i2c_bus_num]->dr); + + if (i2c_wait(I2C_WRITE_BIT) < 0) + break; + } + + return i; +} + +static __inline__ int +__i2c_read(u8 *data, int length) +{ + int i; + + writeb(I2C_CR_MEN | I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0), + &i2c_dev[i2c_bus_num]->cr); + + /* dummy read */ + readb(&i2c_dev[i2c_bus_num]->dr); + + for (i = 0; i < length; i++) { + if (i2c_wait(I2C_READ_BIT) < 0) + break; + + /* Generate ack on last next to last byte */ + if (i == length - 2) + writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK, + &i2c_dev[i2c_bus_num]->cr); + + /* Do not generate stop on last byte */ + if (i == length - 1) + writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX, + &i2c_dev[i2c_bus_num]->cr); + + data[i] = readb(&i2c_dev[i2c_bus_num]->dr); + } + + return i; +} + +int +i2c_read(u8 dev, uint addr, int alen, u8 *data, int length) +{ + int i = -1; /* signal error */ + u8 *a = (u8*)&addr; + + if (i2c_wait4bus() >= 0 + && i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0 + && __i2c_write(&a[4 - alen], alen) == alen) + i = 0; /* No error so far */ + + if (length + && i2c_write_addr(dev, I2C_READ_BIT, 1) != 0) + i = __i2c_read(data, length); + + writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr); + + if (i2c_wait4bus()) /* Wait until STOP */ + debug("i2c_read: wait4bus timed out\n"); + + if (i == length) + return 0; + + return -1; +} + +int +i2c_write(u8 dev, uint addr, int alen, u8 *data, int length) +{ + int i = -1; /* signal error */ + u8 *a = (u8*)&addr; + + if (i2c_wait4bus() >= 0 + && i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0 + && __i2c_write(&a[4 - alen], alen) == alen) { + i = __i2c_write(data, length); + } + + writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr); + if (i2c_wait4bus()) /* Wait until STOP */ + debug("i2c_write: wait4bus timed out\n"); + + if (i == length) + return 0; + + return -1; +} + +int +i2c_probe(uchar chip) +{ + /* For unknow reason the controller will ACK when + * probing for a slave with the same address, so skip + * it. + */ + if (chip == (readb(&i2c_dev[i2c_bus_num]->adr) >> 1)) + return -1; + + return i2c_read(chip, 0, 0, NULL, 0); +} + +int i2c_set_bus_num(unsigned int bus) +{ +#if defined(CONFIG_I2C_MUX) + if (bus < CONFIG_SYS_MAX_I2C_BUS) { + i2c_bus_num = bus; + } else { + int ret; + + ret = i2x_mux_select_mux(bus); + if (ret) + return ret; + i2c_bus_num = 0; + } + i2c_bus_num_mux = bus; +#else +#ifdef CONFIG_SYS_I2C2_OFFSET + if (bus > 1) { +#else + if (bus > 0) { +#endif + return -1; + } + + i2c_bus_num = bus; +#endif + return 0; +} + +int i2c_set_bus_speed(unsigned int speed) +{ + unsigned int i2c_clk = (i2c_bus_num == 1) ? gd->i2c2_clk : gd->i2c1_clk; + + writeb(0, &i2c_dev[i2c_bus_num]->cr); /* stop controller */ + i2c_bus_speed[i2c_bus_num] = + set_i2c_bus_speed(i2c_dev[i2c_bus_num], i2c_clk, speed); + writeb(I2C_CR_MEN, &i2c_dev[i2c_bus_num]->cr); /* start controller */ + + return 0; +} + +unsigned int i2c_get_bus_num(void) +{ +#if defined(CONFIG_I2C_MUX) + return i2c_bus_num_mux; +#else + return i2c_bus_num; +#endif +} + +unsigned int i2c_get_bus_speed(void) +{ + return i2c_bus_speed[i2c_bus_num]; +} + +#endif /* CONFIG_HARD_I2C */ |