i2c: octeon: Split the driver into two parts
Move common functionality into a separate file in preparation of the
re-use from the ThunderX i2c driver.
Functions are slightly re-ordered but no other changes are included.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/busses/i2c-octeon-core.c b/drivers/i2c/busses/i2c-octeon-core.c
new file mode 100644
index 0000000..23384ef
--- /dev/null
+++ b/drivers/i2c/busses/i2c-octeon-core.c
@@ -0,0 +1,810 @@
+/*
+ * (C) Copyright 2009-2010
+ * Nokia Siemens Networks, michael.lawnick.ext@nsn.com
+ *
+ * Portions Copyright (C) 2010 - 2016 Cavium, Inc.
+ *
+ * This file contains the shared part of the driver for the i2c adapter in
+ * Cavium Networks' OCTEON processors and ThunderX SOCs.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include "i2c-octeon-core.h"
+
+/* interrupt service routine */
+irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
+{
+ struct octeon_i2c *i2c = dev_id;
+
+ i2c->int_disable(i2c);
+ wake_up(&i2c->queue);
+
+ return IRQ_HANDLED;
+}
+
+static bool octeon_i2c_test_iflg(struct octeon_i2c *i2c)
+{
+ return (octeon_i2c_ctl_read(i2c) & TWSI_CTL_IFLG);
+}
+
+static bool octeon_i2c_test_ready(struct octeon_i2c *i2c, bool *first)
+{
+ if (octeon_i2c_test_iflg(i2c))
+ return true;
+
+ if (*first) {
+ *first = false;
+ return false;
+ }
+
+ /*
+ * IRQ has signaled an event but IFLG hasn't changed.
+ * Sleep and retry once.
+ */
+ usleep_range(I2C_OCTEON_EVENT_WAIT, 2 * I2C_OCTEON_EVENT_WAIT);
+ return octeon_i2c_test_iflg(i2c);
+}
+
+/**
+ * octeon_i2c_wait - wait for the IFLG to be set
+ * @i2c: The struct octeon_i2c
+ *
+ * Returns 0 on success, otherwise a negative errno.
+ */
+static int octeon_i2c_wait(struct octeon_i2c *i2c)
+{
+ long time_left;
+ bool first = 1;
+
+ /*
+ * Some chip revisions don't assert the irq in the interrupt
+ * controller. So we must poll for the IFLG change.
+ */
+ if (i2c->broken_irq_mode) {
+ u64 end = get_jiffies_64() + i2c->adap.timeout;
+
+ while (!octeon_i2c_test_iflg(i2c) &&
+ time_before64(get_jiffies_64(), end))
+ usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT);
+
+ return octeon_i2c_test_iflg(i2c) ? 0 : -ETIMEDOUT;
+ }
+
+ i2c->int_enable(i2c);
+ time_left = wait_event_timeout(i2c->queue, octeon_i2c_test_ready(i2c, &first),
+ i2c->adap.timeout);
+ i2c->int_disable(i2c);
+
+ if (i2c->broken_irq_check && !time_left &&
+ octeon_i2c_test_iflg(i2c)) {
+ dev_err(i2c->dev, "broken irq connection detected, switching to polling mode.\n");
+ i2c->broken_irq_mode = true;
+ return 0;
+ }
+
+ if (!time_left)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static bool octeon_i2c_hlc_test_valid(struct octeon_i2c *i2c)
+{
+ return (__raw_readq(i2c->twsi_base + SW_TWSI) & SW_TWSI_V) == 0;
+}
+
+static bool octeon_i2c_hlc_test_ready(struct octeon_i2c *i2c, bool *first)
+{
+ /* check if valid bit is cleared */
+ if (octeon_i2c_hlc_test_valid(i2c))
+ return true;
+
+ if (*first) {
+ *first = false;
+ return false;
+ }
+
+ /*
+ * IRQ has signaled an event but valid bit isn't cleared.
+ * Sleep and retry once.
+ */
+ usleep_range(I2C_OCTEON_EVENT_WAIT, 2 * I2C_OCTEON_EVENT_WAIT);
+ return octeon_i2c_hlc_test_valid(i2c);
+}
+
+static void octeon_i2c_hlc_int_clear(struct octeon_i2c *i2c)
+{
+ /* clear ST/TS events, listen for neither */
+ octeon_i2c_write_int(i2c, TWSI_INT_ST_INT | TWSI_INT_TS_INT);
+}
+
+/*
+ * Cleanup low-level state & enable high-level controller.
+ */
+static void octeon_i2c_hlc_enable(struct octeon_i2c *i2c)
+{
+ int try = 0;
+ u64 val;
+
+ if (i2c->hlc_enabled)
+ return;
+ i2c->hlc_enabled = true;
+
+ while (1) {
+ val = octeon_i2c_ctl_read(i2c);
+ if (!(val & (TWSI_CTL_STA | TWSI_CTL_STP)))
+ break;
+
+ /* clear IFLG event */
+ if (val & TWSI_CTL_IFLG)
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
+
+ if (try++ > 100) {
+ pr_err("%s: giving up\n", __func__);
+ break;
+ }
+
+ /* spin until any start/stop has finished */
+ udelay(10);
+ }
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_CE | TWSI_CTL_AAK | TWSI_CTL_ENAB);
+}
+
+static void octeon_i2c_hlc_disable(struct octeon_i2c *i2c)
+{
+ if (!i2c->hlc_enabled)
+ return;
+
+ i2c->hlc_enabled = false;
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
+}
+
+/**
+ * octeon_i2c_hlc_wait - wait for an HLC operation to complete
+ * @i2c: The struct octeon_i2c
+ *
+ * Returns 0 on success, otherwise -ETIMEDOUT.
+ */
+static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
+{
+ bool first = 1;
+ int time_left;
+
+ /*
+ * Some cn38xx boards don't assert the irq in the interrupt
+ * controller. So we must poll for the valid bit change.
+ */
+ if (i2c->broken_irq_mode) {
+ u64 end = get_jiffies_64() + i2c->adap.timeout;
+
+ while (!octeon_i2c_hlc_test_valid(i2c) &&
+ time_before64(get_jiffies_64(), end))
+ usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT);
+
+ return octeon_i2c_hlc_test_valid(i2c) ? 0 : -ETIMEDOUT;
+ }
+
+ i2c->hlc_int_enable(i2c);
+ time_left = wait_event_timeout(i2c->queue,
+ octeon_i2c_hlc_test_ready(i2c, &first),
+ i2c->adap.timeout);
+ i2c->hlc_int_disable(i2c);
+ if (!time_left)
+ octeon_i2c_hlc_int_clear(i2c);
+
+ if (i2c->broken_irq_check && !time_left &&
+ octeon_i2c_hlc_test_valid(i2c)) {
+ dev_err(i2c->dev, "broken irq connection detected, switching to polling mode.\n");
+ i2c->broken_irq_mode = true;
+ return 0;
+ }
+
+ if (!time_left)
+ return -ETIMEDOUT;
+ return 0;
+}
+
+static int octeon_i2c_check_status(struct octeon_i2c *i2c, int final_read)
+{
+ u8 stat = octeon_i2c_stat_read(i2c);
+
+ switch (stat) {
+ /* Everything is fine */
+ case STAT_IDLE:
+ case STAT_AD2W_ACK:
+ case STAT_RXADDR_ACK:
+ case STAT_TXADDR_ACK:
+ case STAT_TXDATA_ACK:
+ return 0;
+
+ /* ACK allowed on pre-terminal bytes only */
+ case STAT_RXDATA_ACK:
+ if (!final_read)
+ return 0;
+ return -EIO;
+
+ /* NAK allowed on terminal byte only */
+ case STAT_RXDATA_NAK:
+ if (final_read)
+ return 0;
+ return -EIO;
+
+ /* Arbitration lost */
+ case STAT_LOST_ARB_38:
+ case STAT_LOST_ARB_68:
+ case STAT_LOST_ARB_78:
+ case STAT_LOST_ARB_B0:
+ return -EAGAIN;
+
+ /* Being addressed as slave, should back off & listen */
+ case STAT_SLAVE_60:
+ case STAT_SLAVE_70:
+ case STAT_GENDATA_ACK:
+ case STAT_GENDATA_NAK:
+ return -EOPNOTSUPP;
+
+ /* Core busy as slave */
+ case STAT_SLAVE_80:
+ case STAT_SLAVE_88:
+ case STAT_SLAVE_A0:
+ case STAT_SLAVE_A8:
+ case STAT_SLAVE_LOST:
+ case STAT_SLAVE_NAK:
+ case STAT_SLAVE_ACK:
+ return -EOPNOTSUPP;
+
+ case STAT_TXDATA_NAK:
+ return -EIO;
+ case STAT_TXADDR_NAK:
+ case STAT_RXADDR_NAK:
+ case STAT_AD2W_NAK:
+ return -ENXIO;
+ default:
+ dev_err(i2c->dev, "unhandled state: %d\n", stat);
+ return -EIO;
+ }
+}
+
+static int octeon_i2c_recovery(struct octeon_i2c *i2c)
+{
+ int ret;
+
+ ret = i2c_recover_bus(&i2c->adap);
+ if (ret)
+ /* recover failed, try hardware re-init */
+ ret = octeon_i2c_init_lowlevel(i2c);
+ return ret;
+}
+
+/**
+ * octeon_i2c_start - send START to the bus
+ * @i2c: The struct octeon_i2c
+ *
+ * Returns 0 on success, otherwise a negative errno.
+ */
+static int octeon_i2c_start(struct octeon_i2c *i2c)
+{
+ int ret;
+ u8 stat;
+
+ octeon_i2c_hlc_disable(i2c);
+
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STA);
+ ret = octeon_i2c_wait(i2c);
+ if (ret)
+ goto error;
+
+ stat = octeon_i2c_stat_read(i2c);
+ if (stat == STAT_START || stat == STAT_REP_START)
+ /* START successful, bail out */
+ return 0;
+
+error:
+ /* START failed, try to recover */
+ ret = octeon_i2c_recovery(i2c);
+ return (ret) ? ret : -EAGAIN;
+}
+
+/* send STOP to the bus */
+static void octeon_i2c_stop(struct octeon_i2c *i2c)
+{
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STP);
+}
+
+/**
+ * octeon_i2c_read - receive data from the bus via low-level controller
+ * @i2c: The struct octeon_i2c
+ * @target: Target address
+ * @data: Pointer to the location to store the data
+ * @rlength: Length of the data
+ * @recv_len: flag for length byte
+ *
+ * The address is sent over the bus, then the data is read.
+ *
+ * Returns 0 on success, otherwise a negative errno.
+ */
+static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
+ u8 *data, u16 *rlength, bool recv_len)
+{
+ int i, result, length = *rlength;
+ bool final_read = false;
+
+ octeon_i2c_data_write(i2c, (target << 1) | 1);
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
+
+ result = octeon_i2c_wait(i2c);
+ if (result)
+ return result;
+
+ /* address OK ? */
+ result = octeon_i2c_check_status(i2c, false);
+ if (result)
+ return result;
+
+ for (i = 0; i < length; i++) {
+ /*
+ * For the last byte to receive TWSI_CTL_AAK must not be set.
+ *
+ * A special case is I2C_M_RECV_LEN where we don't know the
+ * additional length yet. If recv_len is set we assume we're
+ * not reading the final byte and therefore need to set
+ * TWSI_CTL_AAK.
+ */
+ if ((i + 1 == length) && !(recv_len && i == 0))
+ final_read = true;
+
+ /* clear iflg to allow next event */
+ if (final_read)
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
+ else
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_AAK);
+
+ result = octeon_i2c_wait(i2c);
+ if (result)
+ return result;
+
+ data[i] = octeon_i2c_data_read(i2c);
+ if (recv_len && i == 0) {
+ if (data[i] > I2C_SMBUS_BLOCK_MAX + 1)
+ return -EPROTO;
+ length += data[i];
+ }
+
+ result = octeon_i2c_check_status(i2c, final_read);
+ if (result)
+ return result;
+ }
+ *rlength = length;
+ return 0;
+}
+
+/**
+ * octeon_i2c_write - send data to the bus via low-level controller
+ * @i2c: The struct octeon_i2c
+ * @target: Target address
+ * @data: Pointer to the data to be sent
+ * @length: Length of the data
+ *
+ * The address is sent over the bus, then the data.
+ *
+ * Returns 0 on success, otherwise a negative errno.
+ */
+static int octeon_i2c_write(struct octeon_i2c *i2c, int target,
+ const u8 *data, int length)
+{
+ int i, result;
+
+ octeon_i2c_data_write(i2c, target << 1);
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
+
+ result = octeon_i2c_wait(i2c);
+ if (result)
+ return result;
+
+ for (i = 0; i < length; i++) {
+ result = octeon_i2c_check_status(i2c, false);
+ if (result)
+ return result;
+
+ octeon_i2c_data_write(i2c, data[i]);
+ octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
+
+ result = octeon_i2c_wait(i2c);
+ if (result)
+ return result;
+ }
+
+ return 0;
+}
+
+/* high-level-controller pure read of up to 8 bytes */
+static int octeon_i2c_hlc_read(struct octeon_i2c *i2c, struct i2c_msg *msgs)
+{
+ int i, j, ret = 0;
+ u64 cmd;
+
+ octeon_i2c_hlc_enable(i2c);
+ octeon_i2c_hlc_int_clear(i2c);
+
+ cmd = SW_TWSI_V | SW_TWSI_R | SW_TWSI_SOVR;
+ /* SIZE */
+ cmd |= (u64)(msgs[0].len - 1) << SW_TWSI_SIZE_SHIFT;
+ /* A */
+ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
+
+ if (msgs[0].flags & I2C_M_TEN)
+ cmd |= SW_TWSI_OP_10;
+ else
+ cmd |= SW_TWSI_OP_7;
+
+ octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI);
+ ret = octeon_i2c_hlc_wait(i2c);
+ if (ret)
+ goto err;
+
+ cmd = __raw_readq(i2c->twsi_base + SW_TWSI);
+ if ((cmd & SW_TWSI_R) == 0)
+ return -EAGAIN;
+
+ for (i = 0, j = msgs[0].len - 1; i < msgs[0].len && i < 4; i++, j--)
+ msgs[0].buf[j] = (cmd >> (8 * i)) & 0xff;
+
+ if (msgs[0].len > 4) {
+ cmd = __raw_readq(i2c->twsi_base + SW_TWSI_EXT);
+ for (i = 0; i < msgs[0].len - 4 && i < 4; i++, j--)
+ msgs[0].buf[j] = (cmd >> (8 * i)) & 0xff;
+ }
+
+err:
+ return ret;
+}
+
+/* high-level-controller pure write of up to 8 bytes */
+static int octeon_i2c_hlc_write(struct octeon_i2c *i2c, struct i2c_msg *msgs)
+{
+ int i, j, ret = 0;
+ u64 cmd;
+
+ octeon_i2c_hlc_enable(i2c);
+ octeon_i2c_hlc_int_clear(i2c);
+
+ cmd = SW_TWSI_V | SW_TWSI_SOVR;
+ /* SIZE */
+ cmd |= (u64)(msgs[0].len - 1) << SW_TWSI_SIZE_SHIFT;
+ /* A */
+ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
+
+ if (msgs[0].flags & I2C_M_TEN)
+ cmd |= SW_TWSI_OP_10;
+ else
+ cmd |= SW_TWSI_OP_7;
+
+ for (i = 0, j = msgs[0].len - 1; i < msgs[0].len && i < 4; i++, j--)
+ cmd |= (u64)msgs[0].buf[j] << (8 * i);
+
+ if (msgs[0].len > 4) {
+ u64 ext = 0;
+
+ for (i = 0; i < msgs[0].len - 4 && i < 4; i++, j--)
+ ext |= (u64)msgs[0].buf[j] << (8 * i);
+ octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT);
+ }
+
+ octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI);
+ ret = octeon_i2c_hlc_wait(i2c);
+ if (ret)
+ goto err;
+
+ cmd = __raw_readq(i2c->twsi_base + SW_TWSI);
+ if ((cmd & SW_TWSI_R) == 0)
+ return -EAGAIN;
+
+ ret = octeon_i2c_check_status(i2c, false);
+
+err:
+ return ret;
+}
+
+/* high-level-controller composite write+read, msg0=addr, msg1=data */
+static int octeon_i2c_hlc_comp_read(struct octeon_i2c *i2c, struct i2c_msg *msgs)
+{
+ int i, j, ret = 0;
+ u64 cmd;
+
+ octeon_i2c_hlc_enable(i2c);
+
+ cmd = SW_TWSI_V | SW_TWSI_R | SW_TWSI_SOVR;
+ /* SIZE */
+ cmd |= (u64)(msgs[1].len - 1) << SW_TWSI_SIZE_SHIFT;
+ /* A */
+ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
+
+ if (msgs[0].flags & I2C_M_TEN)
+ cmd |= SW_TWSI_OP_10_IA;
+ else
+ cmd |= SW_TWSI_OP_7_IA;
+
+ if (msgs[0].len == 2) {
+ u64 ext = 0;
+
+ cmd |= SW_TWSI_EIA;
+ ext = (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
+ cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT;
+ octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT);
+ } else {
+ cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
+ }
+
+ octeon_i2c_hlc_int_clear(i2c);
+ octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI);
+
+ ret = octeon_i2c_hlc_wait(i2c);
+ if (ret)
+ goto err;
+
+ cmd = __raw_readq(i2c->twsi_base + SW_TWSI);
+ if ((cmd & SW_TWSI_R) == 0)
+ return -EAGAIN;
+
+ for (i = 0, j = msgs[1].len - 1; i < msgs[1].len && i < 4; i++, j--)
+ msgs[1].buf[j] = (cmd >> (8 * i)) & 0xff;
+
+ if (msgs[1].len > 4) {
+ cmd = __raw_readq(i2c->twsi_base + SW_TWSI_EXT);
+ for (i = 0; i < msgs[1].len - 4 && i < 4; i++, j--)
+ msgs[1].buf[j] = (cmd >> (8 * i)) & 0xff;
+ }
+
+err:
+ return ret;
+}
+
+/* high-level-controller composite write+write, m[0]len<=2, m[1]len<=8 */
+static int octeon_i2c_hlc_comp_write(struct octeon_i2c *i2c, struct i2c_msg *msgs)
+{
+ bool set_ext = false;
+ int i, j, ret = 0;
+ u64 cmd, ext = 0;
+
+ octeon_i2c_hlc_enable(i2c);
+
+ cmd = SW_TWSI_V | SW_TWSI_SOVR;
+ /* SIZE */
+ cmd |= (u64)(msgs[1].len - 1) << SW_TWSI_SIZE_SHIFT;
+ /* A */
+ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
+
+ if (msgs[0].flags & I2C_M_TEN)
+ cmd |= SW_TWSI_OP_10_IA;
+ else
+ cmd |= SW_TWSI_OP_7_IA;
+
+ if (msgs[0].len == 2) {
+ cmd |= SW_TWSI_EIA;
+ ext |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
+ set_ext = true;
+ cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT;
+ } else {
+ cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
+ }
+
+ for (i = 0, j = msgs[1].len - 1; i < msgs[1].len && i < 4; i++, j--)
+ cmd |= (u64)msgs[1].buf[j] << (8 * i);
+
+ if (msgs[1].len > 4) {
+ for (i = 0; i < msgs[1].len - 4 && i < 4; i++, j--)
+ ext |= (u64)msgs[1].buf[j] << (8 * i);
+ set_ext = true;
+ }
+ if (set_ext)
+ octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT);
+
+ octeon_i2c_hlc_int_clear(i2c);
+ octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI);
+
+ ret = octeon_i2c_hlc_wait(i2c);
+ if (ret)
+ goto err;
+
+ cmd = __raw_readq(i2c->twsi_base + SW_TWSI);
+ if ((cmd & SW_TWSI_R) == 0)
+ return -EAGAIN;
+
+ ret = octeon_i2c_check_status(i2c, false);
+
+err:
+ return ret;
+}
+
+/**
+ * octeon_i2c_xfer - The driver's master_xfer function
+ * @adap: Pointer to the i2c_adapter structure
+ * @msgs: Pointer to the messages to be processed
+ * @num: Length of the MSGS array
+ *
+ * Returns the number of messages processed, or a negative errno on failure.
+ */
+int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+ struct octeon_i2c *i2c = i2c_get_adapdata(adap);
+ int i, ret = 0;
+
+ if (num == 1) {
+ if (msgs[0].len > 0 && msgs[0].len <= 8) {
+ if (msgs[0].flags & I2C_M_RD)
+ ret = octeon_i2c_hlc_read(i2c, msgs);
+ else
+ ret = octeon_i2c_hlc_write(i2c, msgs);
+ goto out;
+ }
+ } else if (num == 2) {
+ if ((msgs[0].flags & I2C_M_RD) == 0 &&
+ (msgs[1].flags & I2C_M_RECV_LEN) == 0 &&
+ msgs[0].len > 0 && msgs[0].len <= 2 &&
+ msgs[1].len > 0 && msgs[1].len <= 8 &&
+ msgs[0].addr == msgs[1].addr) {
+ if (msgs[1].flags & I2C_M_RD)
+ ret = octeon_i2c_hlc_comp_read(i2c, msgs);
+ else
+ ret = octeon_i2c_hlc_comp_write(i2c, msgs);
+ goto out;
+ }
+ }
+
+ for (i = 0; ret == 0 && i < num; i++) {
+ struct i2c_msg *pmsg = &msgs[i];
+
+ /* zero-length messages are not supported */
+ if (!pmsg->len) {
+ ret = -EOPNOTSUPP;
+ break;
+ }
+
+ ret = octeon_i2c_start(i2c);
+ if (ret)
+ return ret;
+
+ if (pmsg->flags & I2C_M_RD)
+ ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf,
+ &pmsg->len, pmsg->flags & I2C_M_RECV_LEN);
+ else
+ ret = octeon_i2c_write(i2c, pmsg->addr, pmsg->buf,
+ pmsg->len);
+ }
+ octeon_i2c_stop(i2c);
+out:
+ return (ret != 0) ? ret : num;
+}
+
+/* calculate and set clock divisors */
+void octeon_i2c_set_clock(struct octeon_i2c *i2c)
+{
+ int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff;
+ int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000;
+
+ for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) {
+ /*
+ * An mdiv value of less than 2 seems to not work well
+ * with ds1337 RTCs, so we constrain it to larger values.
+ */
+ for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) {
+ /*
+ * For given ndiv and mdiv values check the
+ * two closest thp values.
+ */
+ tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10;
+ tclk *= (1 << ndiv_idx);
+ thp_base = (i2c->sys_freq / (tclk * 2)) - 1;
+
+ for (inc = 0; inc <= 1; inc++) {
+ thp_idx = thp_base + inc;
+ if (thp_idx < 5 || thp_idx > 0xff)
+ continue;
+
+ foscl = i2c->sys_freq / (2 * (thp_idx + 1));
+ foscl = foscl / (1 << ndiv_idx);
+ foscl = foscl / (mdiv_idx + 1) / 10;
+ diff = abs(foscl - i2c->twsi_freq);
+ if (diff < delta_hz) {
+ delta_hz = diff;
+ thp = thp_idx;
+ mdiv = mdiv_idx;
+ ndiv = ndiv_idx;
+ }
+ }
+ }
+ }
+ octeon_i2c_reg_write(i2c, SW_TWSI_OP_TWSI_CLK, thp);
+ octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv);
+}
+
+int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c)
+{
+ u8 status = 0;
+ int tries;
+
+ /* reset controller */
+ octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_RST, 0);
+
+ for (tries = 10; tries && status != STAT_IDLE; tries--) {
+ udelay(1);
+ status = octeon_i2c_stat_read(i2c);
+ if (status == STAT_IDLE)
+ break;
+ }
+
+ if (status != STAT_IDLE) {
+ dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n",
+ __func__, status);
+ return -EIO;
+ }
+
+ /* toggle twice to force both teardowns */
+ octeon_i2c_hlc_enable(i2c);
+ octeon_i2c_hlc_disable(i2c);
+ return 0;
+}
+
+static int octeon_i2c_get_scl(struct i2c_adapter *adap)
+{
+ struct octeon_i2c *i2c = i2c_get_adapdata(adap);
+ u64 state;
+
+ state = octeon_i2c_read_int(i2c);
+ return state & TWSI_INT_SCL;
+}
+
+static void octeon_i2c_set_scl(struct i2c_adapter *adap, int val)
+{
+ struct octeon_i2c *i2c = i2c_get_adapdata(adap);
+
+ octeon_i2c_write_int(i2c, TWSI_INT_SCL_OVR);
+}
+
+static int octeon_i2c_get_sda(struct i2c_adapter *adap)
+{
+ struct octeon_i2c *i2c = i2c_get_adapdata(adap);
+ u64 state;
+
+ state = octeon_i2c_read_int(i2c);
+ return state & TWSI_INT_SDA;
+}
+
+static void octeon_i2c_prepare_recovery(struct i2c_adapter *adap)
+{
+ struct octeon_i2c *i2c = i2c_get_adapdata(adap);
+
+ /*
+ * The stop resets the state machine, does not _transmit_ STOP unless
+ * engine was active.
+ */
+ octeon_i2c_stop(i2c);
+
+ octeon_i2c_hlc_disable(i2c);
+ octeon_i2c_write_int(i2c, 0);
+}
+
+static void octeon_i2c_unprepare_recovery(struct i2c_adapter *adap)
+{
+ struct octeon_i2c *i2c = i2c_get_adapdata(adap);
+
+ octeon_i2c_write_int(i2c, 0);
+}
+
+struct i2c_bus_recovery_info octeon_i2c_recovery_info = {
+ .recover_bus = i2c_generic_scl_recovery,
+ .get_scl = octeon_i2c_get_scl,
+ .set_scl = octeon_i2c_set_scl,
+ .get_sda = octeon_i2c_get_sda,
+ .prepare_recovery = octeon_i2c_prepare_recovery,
+ .unprepare_recovery = octeon_i2c_unprepare_recovery,
+};