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author | Josh Blum <josh@joshknows.com> | 2010-02-10 11:57:58 -0800 |
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committer | Josh Blum <josh@joshknows.com> | 2010-02-10 11:57:58 -0800 |
commit | d088a11bf7c257ba45bf0c37a41e5038b302bc44 (patch) | |
tree | 8bbb4d90285a181c603c117de4504e73066afe48 /firmware/microblaze/lib/i2c.c | |
parent | e2044e13ec4ad94e9739402257134abd92cf1521 (diff) | |
download | uhd-d088a11bf7c257ba45bf0c37a41e5038b302bc44.tar.gz uhd-d088a11bf7c257ba45bf0c37a41e5038b302bc44.tar.bz2 uhd-d088a11bf7c257ba45bf0c37a41e5038b302bc44.zip |
Copied a snapshot of the usrp2 firmware into the microblaze firmware directory in the uhd repo.
Added erllc copyrights to the files created and modified at erllc.
Diffstat (limited to 'firmware/microblaze/lib/i2c.c')
-rw-r--r-- | firmware/microblaze/lib/i2c.c | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/firmware/microblaze/lib/i2c.c b/firmware/microblaze/lib/i2c.c new file mode 100644 index 000000000..3f738733b --- /dev/null +++ b/firmware/microblaze/lib/i2c.c @@ -0,0 +1,127 @@ +/* -*- c -*- */ +/* + * Copyright 2007 Free Software Foundation, Inc. + * + * 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 3 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, see <http://www.gnu.org/licenses/>. + */ + +#include "i2c.h" +#include "memory_map.h" +#include "stdint.h" + +#define MAX_WB_DIV 4 // maximum wishbone divisor (from 100 MHz MASTER_CLK) + +// prescaler divisor values for 100 kHz I2C [uses 5 * SCLK internally] + +#define PRESCALER(wb_div) (((MASTER_CLK_RATE/(wb_div)) / (5 * 100000)) - 1) + +static uint16_t prescaler_values[MAX_WB_DIV+1] = { + 0xffff, // 0: can't happen + PRESCALER(1), // 1: 100 MHz + PRESCALER(2), // 2: 50 MHz + PRESCALER(3), // 3: 33.333 MHz + PRESCALER(4), // 4: 25 MHz +}; + +void +i2c_init(void) +{ + i2c_regs->ctrl = 0; // disable core + + // setup prescaler depending on wishbone divisor + int wb_div = hwconfig_wishbone_divisor(); + if (wb_div > MAX_WB_DIV) + wb_div = MAX_WB_DIV; + + i2c_regs->prescaler_lo = prescaler_values[wb_div] & 0xff; + i2c_regs->prescaler_hi = (prescaler_values[wb_div] >> 8) & 0xff; + + i2c_regs->ctrl = I2C_CTRL_EN; // enable core + + // FIXME interrupt driven? +} + +static inline void +wait_for_xfer(void) +{ + while (i2c_regs->cmd_status & I2C_ST_TIP) // wait for xfer to complete + ; +} + +static inline bool +wait_chk_ack(void) +{ + wait_for_xfer(); + + if ((i2c_regs->cmd_status & I2C_ST_RXACK) != 0){ // target NAK'd + return false; + } + return true; +} + +bool +i2c_read (unsigned char i2c_addr, unsigned char *buf, unsigned int len) +{ + if (len == 0) // reading zero bytes always works + return true; + + while (i2c_regs->cmd_status & I2C_ST_BUSY) + ; + + i2c_regs->data = (i2c_addr << 1) | 1; // 7 bit address and read bit (1) + // generate START and write addr + i2c_regs->cmd_status = I2C_CMD_WR | I2C_CMD_START; + if (!wait_chk_ack()) + goto fail; + + for (; len > 0; buf++, len--){ + i2c_regs->cmd_status = I2C_CMD_RD | (len == 1 ? (I2C_CMD_NACK | I2C_CMD_STOP) : 0); + wait_for_xfer(); + *buf = i2c_regs->data; + } + return true; + + fail: + i2c_regs->cmd_status = I2C_CMD_STOP; // generate STOP + return false; +} + + +bool +i2c_write(unsigned char i2c_addr, const unsigned char *buf, unsigned int len) +{ + while (i2c_regs->cmd_status & I2C_ST_BUSY) + ; + + i2c_regs->data = (i2c_addr << 1) | 0; // 7 bit address and write bit (0) + + // generate START and write addr (and maybe STOP) + i2c_regs->cmd_status = I2C_CMD_WR | I2C_CMD_START | (len == 0 ? I2C_CMD_STOP : 0); + if (!wait_chk_ack()) + goto fail; + + for (; len > 0; buf++, len--){ + i2c_regs->data = *buf; + i2c_regs->cmd_status = I2C_CMD_WR | (len == 1 ? I2C_CMD_STOP : 0); + if (!wait_chk_ack()) + goto fail; + } + return true; + + fail: + i2c_regs->cmd_status = I2C_CMD_STOP; // generate STOP + return false; +} + + |