diff options
Diffstat (limited to 'drivers/video/fbdev/mb862xx/mb862xx-i2c.c')
| -rw-r--r-- | drivers/video/fbdev/mb862xx/mb862xx-i2c.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/drivers/video/fbdev/mb862xx/mb862xx-i2c.c b/drivers/video/fbdev/mb862xx/mb862xx-i2c.c new file mode 100644 index 0000000000..ffdb1597d3 --- /dev/null +++ b/drivers/video/fbdev/mb862xx/mb862xx-i2c.c @@ -0,0 +1,168 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Coral-P(A)/Lime I2C adapter driver + * + * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de> + */ + +#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; +} + +static 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) +{ + mb862xx_i2c_adapter.algo_data = par; + par->adap = &mb862xx_i2c_adapter; + + return i2c_add_adapter(par->adap); +} + +void mb862xx_i2c_exit(struct mb862xxfb_par *par) +{ + if (par->adap) { + i2c_del_adapter(par->adap); + par->adap = NULL; + } +} |