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Diffstat (limited to 'drivers/staging/solo6x10/i2c.c')
-rw-r--r--drivers/staging/solo6x10/i2c.c330
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 000000000000..ef95a500b4da
--- /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;
+ }
+}
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