diff options
Diffstat (limited to 'arch/ppc/cpu/mpc8220/i2c.c')
| -rw-r--r-- | arch/ppc/cpu/mpc8220/i2c.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/arch/ppc/cpu/mpc8220/i2c.c b/arch/ppc/cpu/mpc8220/i2c.c new file mode 100644 index 0000000..76ecdf1 --- /dev/null +++ b/arch/ppc/cpu/mpc8220/i2c.c @@ -0,0 +1,390 @@ +/* + * (C) Copyright 2004, Freescale, Inc + * TsiChung Liew, Tsi-Chung.Liew@freescale.com. + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * 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> + +DECLARE_GLOBAL_DATA_PTR; + +#ifdef CONFIG_HARD_I2C + +#include <mpc8220.h> +#include <i2c.h> + +typedef struct mpc8220_i2c { + volatile u32 adr; /* I2Cn + 0x00 */ + volatile u32 fdr; /* I2Cn + 0x04 */ + volatile u32 cr; /* I2Cn + 0x08 */ + volatile u32 sr; /* I2Cn + 0x0C */ + volatile u32 dr; /* I2Cn + 0x10 */ +} i2c_t; + +/* I2Cn control register bits */ +#define I2C_EN 0x80 +#define I2C_IEN 0x40 +#define I2C_STA 0x20 +#define I2C_TX 0x10 +#define I2C_TXAK 0x08 +#define I2C_RSTA 0x04 +#define I2C_INIT_MASK (I2C_EN | I2C_STA | I2C_TX | I2C_RSTA) + +/* I2Cn status register bits */ +#define I2C_CF 0x80 +#define I2C_AAS 0x40 +#define I2C_BB 0x20 +#define I2C_AL 0x10 +#define I2C_SRW 0x04 +#define I2C_IF 0x02 +#define I2C_RXAK 0x01 + +#define I2C_TIMEOUT 100 +#define I2C_RETRIES 1 + +struct mpc8220_i2c_tap { + int scl2tap; + int tap2tap; +}; + +static int mpc_reg_in (volatile u32 * reg); +static void mpc_reg_out (volatile u32 * reg, int val, int mask); +static int wait_for_bb (void); +static int wait_for_pin (int *status); +static int do_address (uchar chip, char rdwr_flag); +static int send_bytes (uchar chip, char *buf, int len); +static int receive_bytes (uchar chip, char *buf, int len); +static int mpc_get_fdr (int); + +static int mpc_reg_in (volatile u32 * reg) +{ + int ret; + ret = *reg >> 24; + __asm__ __volatile__ ("eieio"); + return ret; +} + +static void mpc_reg_out (volatile u32 * reg, int val, int mask) +{ + int tmp; + + if (!mask) { + *reg = val << 24; + } else { + tmp = mpc_reg_in (reg); + *reg = ((tmp & ~mask) | (val & mask)) << 24; + } + __asm__ __volatile__ ("eieio"); + + return; +} + +static int wait_for_bb (void) +{ + i2c_t *regs = (i2c_t *) MMAP_I2C; + int timeout = I2C_TIMEOUT; + int status; + + status = mpc_reg_in (®s->sr); + + while (timeout-- && (status & I2C_BB)) { +#if 1 + volatile int temp; + + mpc_reg_out (®s->cr, I2C_STA, I2C_STA); + temp = mpc_reg_in (®s->dr); + mpc_reg_out (®s->cr, 0, I2C_STA); + mpc_reg_out (®s->cr, 0, 0); + mpc_reg_out (®s->cr, I2C_EN, 0); +#endif + udelay (1000); + status = mpc_reg_in (®s->sr); + } + + return (status & I2C_BB); +} + +static int wait_for_pin (int *status) +{ + i2c_t *regs = (i2c_t *) MMAP_I2C; + int timeout = I2C_TIMEOUT; + + *status = mpc_reg_in (®s->sr); + + while (timeout-- && !(*status & I2C_IF)) { + udelay (1000); + *status = mpc_reg_in (®s->sr); + } + + if (!(*status & I2C_IF)) { + return -1; + } + + mpc_reg_out (®s->sr, 0, I2C_IF); + return 0; +} + +static int do_address (uchar chip, char rdwr_flag) +{ + i2c_t *regs = (i2c_t *) MMAP_I2C; + int status; + + chip <<= 1; + + if (rdwr_flag) + chip |= 1; + + mpc_reg_out (®s->cr, I2C_TX, I2C_TX); + mpc_reg_out (®s->dr, chip, 0); + + if (wait_for_pin (&status)) + return -2; + if (status & I2C_RXAK) + return -3; + return 0; +} + +static int send_bytes (uchar chip, char *buf, int len) +{ + i2c_t *regs = (i2c_t *) MMAP_I2C; + int wrcount; + int status; + + for (wrcount = 0; wrcount < len; ++wrcount) { + + mpc_reg_out (®s->dr, buf[wrcount], 0); + + if (wait_for_pin (&status)) + break; + + if (status & I2C_RXAK) + break; + + } + + return !(wrcount == len); + return 0; +} + +static int receive_bytes (uchar chip, char *buf, int len) +{ + i2c_t *regs = (i2c_t *) MMAP_I2C; + int dummy = 1; + int rdcount = 0; + int status; + int i; + + mpc_reg_out (®s->cr, 0, I2C_TX); + + for (i = 0; i < len; ++i) { + buf[rdcount] = mpc_reg_in (®s->dr); + + if (dummy) + dummy = 0; + else + rdcount++; + + if (wait_for_pin (&status)) + return -4; + } + + mpc_reg_out (®s->cr, I2C_TXAK, I2C_TXAK); + buf[rdcount++] = mpc_reg_in (®s->dr); + + if (wait_for_pin (&status)) + return -5; + + mpc_reg_out (®s->cr, 0, I2C_TXAK); + return 0; +} + +/**************** I2C API ****************/ + +void i2c_init (int speed, int saddr) +{ + i2c_t *regs = (i2c_t *) MMAP_I2C; + + mpc_reg_out (®s->cr, 0, 0); + mpc_reg_out (®s->adr, saddr << 1, 0); + + /* Set clock + */ + mpc_reg_out (®s->fdr, mpc_get_fdr (speed), 0); + + /* Enable module + */ + mpc_reg_out (®s->cr, I2C_EN, I2C_INIT_MASK); + mpc_reg_out (®s->sr, 0, I2C_IF); + return; +} + +static int mpc_get_fdr (int speed) +{ + static int fdr = -1; + + if (fdr == -1) { + ulong best_speed = 0; + ulong divider; + ulong ipb, scl; + ulong bestmatch = 0xffffffffUL; + int best_i = 0, best_j = 0, i, j; + int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8 }; + struct mpc8220_i2c_tap scltap[] = { + {4, 1}, + {4, 2}, + {6, 4}, + {6, 8}, + {14, 16}, + {30, 32}, + {62, 64}, + {126, 128} + }; + + ipb = gd->bus_clk; + for (i = 7; i >= 0; i--) { + for (j = 7; j >= 0; j--) { + scl = 2 * (scltap[j].scl2tap + + (SCL_Tap[i] - + 1) * scltap[j].tap2tap + 2); + if (ipb <= speed * scl) { + if ((speed * scl - ipb) < bestmatch) { + bestmatch = speed * scl - ipb; + best_i = i; + best_j = j; + best_speed = ipb / scl; + } + } + } + } + divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2); + if (gd->flags & GD_FLG_RELOC) { + fdr = divider; + } else { + printf ("%ld kHz, ", best_speed / 1000); + return divider; + } + } + + return fdr; +} + +int i2c_probe (uchar chip) +{ + i2c_t *regs = (i2c_t *) MMAP_I2C; + int i; + + for (i = 0; i < I2C_RETRIES; i++) { + mpc_reg_out (®s->cr, I2C_STA, I2C_STA); + + if (!do_address (chip, 0)) { + mpc_reg_out (®s->cr, 0, I2C_STA); + break; + } + + mpc_reg_out (®s->cr, 0, I2C_STA); + udelay (50); + } + + return (i == I2C_RETRIES); +} + +int i2c_read (uchar chip, uint addr, int alen, uchar * buf, int len) +{ + uchar xaddr[4]; + i2c_t *regs = (i2c_t *) MMAP_I2C; + int ret = -1; + + xaddr[0] = (addr >> 24) & 0xFF; + xaddr[1] = (addr >> 16) & 0xFF; + xaddr[2] = (addr >> 8) & 0xFF; + xaddr[3] = addr & 0xFF; + + if (wait_for_bb ()) { + printf ("i2c_read: bus is busy\n"); + goto Done; + } + + mpc_reg_out (®s->cr, I2C_STA, I2C_STA); + if (do_address (chip, 0)) { + printf ("i2c_read: failed to address chip\n"); + goto Done; + } + + if (send_bytes (chip, (char *)&xaddr[4 - alen], alen)) { + printf ("i2c_read: send_bytes failed\n"); + goto Done; + } + + mpc_reg_out (®s->cr, I2C_RSTA, I2C_RSTA); + if (do_address (chip, 1)) { + printf ("i2c_read: failed to address chip\n"); + goto Done; + } + + if (receive_bytes (chip, (char *)buf, len)) { + printf ("i2c_read: receive_bytes failed\n"); + goto Done; + } + + ret = 0; + Done: + mpc_reg_out (®s->cr, 0, I2C_STA); + return ret; +} + +int i2c_write (uchar chip, uint addr, int alen, uchar * buf, int len) +{ + uchar xaddr[4]; + i2c_t *regs = (i2c_t *) MMAP_I2C; + int ret = -1; + + xaddr[0] = (addr >> 24) & 0xFF; + xaddr[1] = (addr >> 16) & 0xFF; + xaddr[2] = (addr >> 8) & 0xFF; + xaddr[3] = addr & 0xFF; + + if (wait_for_bb ()) { + printf ("i2c_write: bus is busy\n"); + goto Done; + } + + mpc_reg_out (®s->cr, I2C_STA, I2C_STA); + if (do_address (chip, 0)) { + printf ("i2c_write: failed to address chip\n"); + goto Done; + } + + if (send_bytes (chip, (char *)&xaddr[4 - alen], alen)) { + printf ("i2c_write: send_bytes failed\n"); + goto Done; + } + + if (send_bytes (chip, (char *)buf, len)) { + printf ("i2c_write: send_bytes failed\n"); + goto Done; + } + + ret = 0; + Done: + mpc_reg_out (®s->cr, 0, I2C_STA); + return ret; +} + +#endif /* CONFIG_HARD_I2C */ |