video: mb862xx: add support for controller's I2C bus adapter

Add adapter driver for I2C adapter in Coral-P(A)/Lime GDCs.
So we can easily access devices on controller's I2C bus using
i2c-dev interface.

Signed-off-by: Anatolij Gustschin <agust@denx.de>

1 files changed, 177 insertions, 0 deletions

diff --git a/drivers/video/mb862xx/mb862xx-i2c.c b/drivers/video/mb862xx/mb862xx-i2c.c
new file mode 100644
index 000000000000..cb77d3b4657d
--- /dev/null
+++ b/drivers/video/mb862xx/mb862xx-i2c.c
@@ -0,0 +1,177 @@
+/*
+ * 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 "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(1);
+                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;
+        }
+}