/* * Coral-P(A)/Lime I2C adapter driver * * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de> * * 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. * */ #include <linux/fb.h> #include <linux/i2c.h> #include <linux/io.h> #include <linux/delay.h> #include <linux/export.h> #include "mb862xxfb.h" #include "mb862xx_reg.h" static int mb862xx_i2c_wait_event(struct i2c_adapter *adap) { struct mb862xxfb_par *par = adap->algo_data; u32 reg; do { udelay(10); reg = inreg(i2c, GC_I2C_BCR); if (reg & (I2C_INT | I2C_BER)) break; } while (1); return (reg & I2C_BER) ? 0 : 1; } static int mb862xx_i2c_do_address(struct i2c_adapter *adap, int addr) { struct mb862xxfb_par *par = adap->algo_data; outreg(i2c, GC_I2C_DAR, addr); outreg(i2c, GC_I2C_CCR, I2C_CLOCK_AND_ENABLE); outreg(i2c, GC_I2C_BCR, par->i2c_rs ? I2C_REPEATED_START : I2C_START); if (!mb862xx_i2c_wait_event(adap)) return -EIO; par->i2c_rs = !(inreg(i2c, GC_I2C_BSR) & I2C_LRB); return par->i2c_rs; } static int mb862xx_i2c_write_byte(struct i2c_adapter *adap, u8 byte) { struct mb862xxfb_par *par = adap->algo_data; outreg(i2c, GC_I2C_DAR, byte); outreg(i2c, GC_I2C_BCR, I2C_START); if (!mb862xx_i2c_wait_event(adap)) return -EIO; return !(inreg(i2c, GC_I2C_BSR) & I2C_LRB); } static int mb862xx_i2c_read_byte(struct i2c_adapter *adap, u8 *byte, int last) { struct mb862xxfb_par *par = adap->algo_data; outreg(i2c, GC_I2C_BCR, I2C_START | (last ? 0 : I2C_ACK)); if (!mb862xx_i2c_wait_event(adap)) return 0; *byte = inreg(i2c, GC_I2C_DAR); return 1; } void mb862xx_i2c_stop(struct i2c_adapter *adap) { struct mb862xxfb_par *par = adap->algo_data; outreg(i2c, GC_I2C_BCR, I2C_STOP); outreg(i2c, GC_I2C_CCR, I2C_DISABLE); par->i2c_rs = 0; } static int mb862xx_i2c_read(struct i2c_adapter *adap, struct i2c_msg *m) { int i, ret = 0; int last = m->len - 1; for (i = 0; i < m->len; i++) { if (!mb862xx_i2c_read_byte(adap, &m->buf[i], i == last)) { ret = -EIO; break; } } return ret; } static int mb862xx_i2c_write(struct i2c_adapter *adap, struct i2c_msg *m) { int i, ret = 0; for (i = 0; i < m->len; i++) { if (!mb862xx_i2c_write_byte(adap, m->buf[i])) { ret = -EIO; break; } } return ret; } static int mb862xx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct mb862xxfb_par *par = adap->algo_data; struct i2c_msg *m; int addr; int i = 0, err = 0; dev_dbg(par->dev, "%s: %d msgs\n", __func__, num); for (i = 0; i < num; i++) { m = &msgs[i]; if (!m->len) { dev_dbg(par->dev, "%s: null msgs\n", __func__); continue; } addr = m->addr; if (m->flags & I2C_M_RD) addr |= 1; err = mb862xx_i2c_do_address(adap, addr); if (err < 0) break; if (m->flags & I2C_M_RD) err = mb862xx_i2c_read(adap, m); else err = mb862xx_i2c_write(adap, m); } if (i) mb862xx_i2c_stop(adap); return (err < 0) ? err : i; } static u32 mb862xx_func(struct i2c_adapter *adap) { return I2C_FUNC_SMBUS_BYTE_DATA; } static const struct i2c_algorithm mb862xx_algo = { .master_xfer = mb862xx_xfer, .functionality = mb862xx_func, }; static struct i2c_adapter mb862xx_i2c_adapter = { .name = "MB862xx I2C adapter", .algo = &mb862xx_algo, .owner = THIS_MODULE, }; int mb862xx_i2c_init(struct mb862xxfb_par *par) { int ret; mb862xx_i2c_adapter.algo_data = par; par->adap = &mb862xx_i2c_adapter; ret = i2c_add_adapter(par->adap); if (ret < 0) { dev_err(par->dev, "failed to add %s\n", mb862xx_i2c_adapter.name); } return ret; } void mb862xx_i2c_exit(struct mb862xxfb_par *par) { if (par->adap) { i2c_del_adapter(par->adap); par->adap = NULL; } }