1 files changed, 330 insertions, 0 deletions

diff --git a/drivers/staging/solo6x10/i2c.c b/drivers/staging/solo6x10/i2c.c
new file mode 100644
index 00000000000..ef95a500b4d
--- /dev/null
+++ b/drivers/staging/solo6x10/i2c.c
@@ -0,0 +1,330 @@
+/*
+ * Copyright (C) 2010 Bluecherry, LLC www.bluecherrydvr.com
+ * Copyright (C) 2010 Ben Collins <bcollins@bluecherry.net>
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+/* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c
+ * channel. The bus can only handle one i2c event at a time. The below handles
+ * this all wrong. We should be using the status registers to see if the bus
+ * is in use, and have a global lock to check the status register. Also,
+ * the bulk of the work should be handled out-of-interrupt. The ugly loops
+ * that occur during interrupt scare me. The ISR should merely signal
+ * thread context, ACK the interrupt, and move on. -- BenC */
+
+#include <linux/kernel.h>
+#include "solo6x10.h"
+
+u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)
+{
+        struct i2c_msg msgs[2];
+        u8 data;
+
+        msgs[0].flags = 0;
+        msgs[0].addr = addr;
+        msgs[0].len = 1;
+        msgs[0].buf = &off;
+
+        msgs[1].flags = I2C_M_RD;
+        msgs[1].addr = addr;
+        msgs[1].len = 1;
+        msgs[1].buf = &data;
+
+        i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);
+
+        return data;
+}
+
+void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,
+                        u8 off, u8 data)
+{
+        struct i2c_msg msgs;
+        u8 buf[2];
+
+        buf[0] = off;
+        buf[1] = data;
+        msgs.flags = 0;
+        msgs.addr = addr;
+        msgs.len = 2;
+        msgs.buf = buf;
+
+        i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);
+}
+
+static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)
+{
+        u32 ctrl;
+
+        ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);
+
+        if (solo_dev->i2c_state == IIC_STATE_START)
+                ctrl |= SOLO_IIC_START;
+
+        if (wr) {
+                ctrl |= SOLO_IIC_WRITE;
+        } else {
+                ctrl |= SOLO_IIC_READ;
+                if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))
+                        ctrl |= SOLO_IIC_ACK_EN;
+        }
+
+        if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)
+                ctrl |= SOLO_IIC_STOP;
+
+        solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);
+}
+
+static void solo_i2c_start(struct solo_dev *solo_dev)
+{
+        u32 addr = solo_dev->i2c_msg->addr << 1;
+
+        if (solo_dev->i2c_msg->flags & I2C_M_RD)
+                addr |= 1;
+
+        solo_dev->i2c_state = IIC_STATE_START;
+        solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);
+        solo_i2c_flush(solo_dev, 1);
+}
+
+static void solo_i2c_stop(struct solo_dev *solo_dev)
+{
+        solo_irq_off(solo_dev, SOLO_IRQ_IIC);
+        solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
+        solo_dev->i2c_state = IIC_STATE_STOP;
+        wake_up(&solo_dev->i2c_wait);
+}
+
+static int solo_i2c_handle_read(struct solo_dev *solo_dev)
+{
+prepare_read:
+        if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
+                solo_i2c_flush(solo_dev, 0);
+                return 0;
+        }
+
+        solo_dev->i2c_msg_ptr = 0;
+        solo_dev->i2c_msg++;
+        solo_dev->i2c_msg_num--;
+
+        if (solo_dev->i2c_msg_num == 0) {
+                solo_i2c_stop(solo_dev);
+                return 0;
+        }
+
+        if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
+                solo_i2c_start(solo_dev);
+        } else {
+                if (solo_dev->i2c_msg->flags & I2C_M_RD)
+                        goto prepare_read;
+                else
+                        solo_i2c_stop(solo_dev);
+        }
+
+        return 0;
+}
+
+static int solo_i2c_handle_write(struct solo_dev *solo_dev)
+{
+retry_write:
+        if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
+                solo_reg_write(solo_dev, SOLO_IIC_TXD,
+                               solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);
+                solo_dev->i2c_msg_ptr++;
+                solo_i2c_flush(solo_dev, 1);
+                return 0;
+        }
+
+        solo_dev->i2c_msg_ptr = 0;
+        solo_dev->i2c_msg++;
+        solo_dev->i2c_msg_num--;
+
+        if (solo_dev->i2c_msg_num == 0) {
+                solo_i2c_stop(solo_dev);
+                return 0;
+        }
+
+        if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
+                solo_i2c_start(solo_dev);
+        } else {
+                if (solo_dev->i2c_msg->flags & I2C_M_RD)
+                        solo_i2c_stop(solo_dev);
+                else
+                        goto retry_write;
+        }
+
+        return 0;
+}
+
+int solo_i2c_isr(struct solo_dev *solo_dev)
+{
+        u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);
+        int ret = -EINVAL;
+
+        solo_reg_write(solo_dev, SOLO_IRQ_STAT, SOLO_IRQ_IIC);
+
+        if (status & (SOLO_IIC_STATE_TRNS & SOLO_IIC_STATE_SIG_ERR) ||
+            solo_dev->i2c_id < 0) {
+                solo_i2c_stop(solo_dev);
+                return -ENXIO;
+        }
+
+        switch (solo_dev->i2c_state) {
+        case IIC_STATE_START:
+                if (solo_dev->i2c_msg->flags & I2C_M_RD) {
+                        solo_dev->i2c_state = IIC_STATE_READ;
+                        ret = solo_i2c_handle_read(solo_dev);
+                        break;
+                }
+
+                solo_dev->i2c_state = IIC_STATE_WRITE;
+        case IIC_STATE_WRITE:
+                ret = solo_i2c_handle_write(solo_dev);
+                break;
+
+        case IIC_STATE_READ:
+                solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =
+                        solo_reg_read(solo_dev, SOLO_IIC_RXD);
+                solo_dev->i2c_msg_ptr++;
+
+                ret = solo_i2c_handle_read(solo_dev);
+                break;
+
+        default:
+                solo_i2c_stop(solo_dev);
+        }
+
+        return ret;
+}
+
+static int solo_i2c_master_xfer(struct i2c_adapter *adap,
+                                struct i2c_msg msgs[], int num)
+{
+        struct solo_dev *solo_dev = adap->algo_data;
+        unsigned long timeout;
+        int ret;
+        int i;
+        DEFINE_WAIT(wait);
+
+        for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
+                if (&solo_dev->i2c_adap[i] == adap)
+                        break;
+        }
+
+        if (i == SOLO_I2C_ADAPTERS)
+                return num; /* XXX Right return value for failure? */
+
+        mutex_lock(&solo_dev->i2c_mutex);
+        solo_dev->i2c_id = i;
+        solo_dev->i2c_msg = msgs;
+        solo_dev->i2c_msg_num = num;
+        solo_dev->i2c_msg_ptr = 0;
+
+        solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
+        solo_irq_on(solo_dev, SOLO_IRQ_IIC);
+        solo_i2c_start(solo_dev);
+
+        timeout = HZ / 2;
+
+        for (;;) {
+                prepare_to_wait(&solo_dev->i2c_wait, &wait, TASK_INTERRUPTIBLE);
+
+                if (solo_dev->i2c_state == IIC_STATE_STOP)
+                        break;
+
+                timeout = schedule_timeout(timeout);
+                if (!timeout)
+                        break;
+
+                if (signal_pending(current))
+                        break;
+        }
+
+        finish_wait(&solo_dev->i2c_wait, &wait);
+        ret = num - solo_dev->i2c_msg_num;
+        solo_dev->i2c_state = IIC_STATE_IDLE;
+        solo_dev->i2c_id = -1;
+
+        mutex_unlock(&solo_dev->i2c_mutex);
+
+        return ret;
+}
+
+static u32 solo_i2c_functionality(struct i2c_adapter *adap)
+{
+        return I2C_FUNC_I2C;
+}
+
+static struct i2c_algorithm solo_i2c_algo = {
+        .master_xfer    = solo_i2c_master_xfer,
+        .functionality  = solo_i2c_functionality,
+};
+
+int solo_i2c_init(struct solo_dev *solo_dev)
+{
+        int i;
+        int ret;
+
+        solo_reg_write(solo_dev, SOLO_IIC_CFG,
+                       SOLO_IIC_PRESCALE(8) | SOLO_IIC_ENABLE);
+
+        solo_dev->i2c_id = -1;
+        solo_dev->i2c_state = IIC_STATE_IDLE;
+        init_waitqueue_head(&solo_dev->i2c_wait);
+        mutex_init(&solo_dev->i2c_mutex);
+
+        for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
+                struct i2c_adapter *adap = &solo_dev->i2c_adap[i];
+
+                snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d", SOLO6X10_NAME, i);
+                adap->algo = &solo_i2c_algo;
+                adap->algo_data = solo_dev;
+                adap->retries = 1;
+                adap->dev.parent = &solo_dev->pdev->dev;
+
+                ret = i2c_add_adapter(adap);
+                if (ret) {
+                        adap->algo_data = NULL;
+                        break;
+                }
+        }
+
+        if (ret) {
+                for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
+                        if (!solo_dev->i2c_adap[i].algo_data)
+                                break;
+                        i2c_del_adapter(&solo_dev->i2c_adap[i]);
+                        solo_dev->i2c_adap[i].algo_data = NULL;
+                }
+                return ret;
+        }
+
+        dev_info(&solo_dev->pdev->dev, "Enabled %d i2c adapters\n",
+                 SOLO_I2C_ADAPTERS);
+
+        return 0;
+}
+
+void solo_i2c_exit(struct solo_dev *solo_dev)
+{
+        int i;
+
+        for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
+                if (!solo_dev->i2c_adap[i].algo_data)
+                        continue;
+                i2c_del_adapter(&solo_dev->i2c_adap[i]);
+                solo_dev->i2c_adap[i].algo_data = NULL;
+        }
+}