1 files changed, 234 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/bit.c b/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/bit.c
new file mode 100644
index 000000000000..813ffc96e864
--- /dev/null
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/bit.c
@@ -0,0 +1,234 @@
+/*
+ * Copyright 2012 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: Ben Skeggs
+ */
+
+#include "priv.h"
+
+#ifdef CONFIG_NOUVEAU_I2C_INTERNAL
+#define T_TIMEOUT  2200000
+#define T_RISEFALL 1000
+#define T_HOLD     5000
+
+static inline void
+i2c_drive_scl(struct nouveau_i2c_port *port, int state)
+{
+        port->func->drive_scl(port, state);
+}
+
+static inline void
+i2c_drive_sda(struct nouveau_i2c_port *port, int state)
+{
+        port->func->drive_sda(port, state);
+}
+
+static inline int
+i2c_sense_scl(struct nouveau_i2c_port *port)
+{
+        return port->func->sense_scl(port);
+}
+
+static inline int
+i2c_sense_sda(struct nouveau_i2c_port *port)
+{
+        return port->func->sense_sda(port);
+}
+
+static void
+i2c_delay(struct nouveau_i2c_port *port, u32 nsec)
+{
+        udelay((nsec + 500) / 1000);
+}
+
+static bool
+i2c_raise_scl(struct nouveau_i2c_port *port)
+{
+        u32 timeout = T_TIMEOUT / T_RISEFALL;
+
+        i2c_drive_scl(port, 1);
+        do {
+                i2c_delay(port, T_RISEFALL);
+        } while (!i2c_sense_scl(port) && --timeout);
+
+        return timeout != 0;
+}
+
+static int
+i2c_start(struct nouveau_i2c_port *port)
+{
+        int ret = 0;
+
+        if (!i2c_sense_scl(port) ||
+            !i2c_sense_sda(port)) {
+                i2c_drive_scl(port, 0);
+                i2c_drive_sda(port, 1);
+                if (!i2c_raise_scl(port))
+                        ret = -EBUSY;
+        }
+
+        i2c_drive_sda(port, 0);
+        i2c_delay(port, T_HOLD);
+        i2c_drive_scl(port, 0);
+        i2c_delay(port, T_HOLD);
+        return ret;
+}
+
+static void
+i2c_stop(struct nouveau_i2c_port *port)
+{
+        i2c_drive_scl(port, 0);
+        i2c_drive_sda(port, 0);
+        i2c_delay(port, T_RISEFALL);
+
+        i2c_drive_scl(port, 1);
+        i2c_delay(port, T_HOLD);
+        i2c_drive_sda(port, 1);
+        i2c_delay(port, T_HOLD);
+}
+
+static int
+i2c_bitw(struct nouveau_i2c_port *port, int sda)
+{
+        i2c_drive_sda(port, sda);
+        i2c_delay(port, T_RISEFALL);
+
+        if (!i2c_raise_scl(port))
+                return -ETIMEDOUT;
+        i2c_delay(port, T_HOLD);
+
+        i2c_drive_scl(port, 0);
+        i2c_delay(port, T_HOLD);
+        return 0;
+}
+
+static int
+i2c_bitr(struct nouveau_i2c_port *port)
+{
+        int sda;
+
+        i2c_drive_sda(port, 1);
+        i2c_delay(port, T_RISEFALL);
+
+        if (!i2c_raise_scl(port))
+                return -ETIMEDOUT;
+        i2c_delay(port, T_HOLD);
+
+        sda = i2c_sense_sda(port);
+
+        i2c_drive_scl(port, 0);
+        i2c_delay(port, T_HOLD);
+        return sda;
+}
+
+static int
+i2c_get_byte(struct nouveau_i2c_port *port, u8 *byte, bool last)
+{
+        int i, bit;
+
+        *byte = 0;
+        for (i = 7; i >= 0; i--) {
+                bit = i2c_bitr(port);
+                if (bit < 0)
+                        return bit;
+                *byte |= bit << i;
+        }
+
+        return i2c_bitw(port, last ? 1 : 0);
+}
+
+static int
+i2c_put_byte(struct nouveau_i2c_port *port, u8 byte)
+{
+        int i, ret;
+        for (i = 7; i >= 0; i--) {
+                ret = i2c_bitw(port, !!(byte & (1 << i)));
+                if (ret < 0)
+                        return ret;
+        }
+
+        ret = i2c_bitr(port);
+        if (ret == 1) /* nack */
+                ret = -EIO;
+        return ret;
+}
+
+static int
+i2c_addr(struct nouveau_i2c_port *port, struct i2c_msg *msg)
+{
+        u32 addr = msg->addr << 1;
+        if (msg->flags & I2C_M_RD)
+                addr |= 1;
+        return i2c_put_byte(port, addr);
+}
+
+static int
+i2c_bit_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+        struct nouveau_i2c_port *port = adap->algo_data;
+        struct i2c_msg *msg = msgs;
+        int ret = 0, mcnt = num;
+
+        ret = nouveau_i2c(port)->acquire(port, nsecs_to_jiffies(T_TIMEOUT));
+        if (ret)
+                return ret;
+
+        while (!ret && mcnt--) {
+                u8 remaining = msg->len;
+                u8 *ptr = msg->buf;
+
+                ret = i2c_start(port);
+                if (ret == 0)
+                        ret = i2c_addr(port, msg);
+
+                if (msg->flags & I2C_M_RD) {
+                        while (!ret && remaining--)
+                                ret = i2c_get_byte(port, ptr++, !remaining);
+                } else {
+                        while (!ret && remaining--)
+                                ret = i2c_put_byte(port, *ptr++);
+                }
+
+                msg++;
+        }
+
+        i2c_stop(port);
+        nouveau_i2c(port)->release(port);
+        return (ret < 0) ? ret : num;
+}
+#else
+static int
+i2c_bit_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+        return -ENODEV;
+}
+#endif
+
+static u32
+i2c_bit_func(struct i2c_adapter *adap)
+{
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+const struct i2c_algorithm nouveau_i2c_bit_algo = {
+        .master_xfer = i2c_bit_xfer,
+        .functionality = i2c_bit_func
+};