[U-Boot] [PATCH V2 3/4] i2c: rewrite mvtwsi, support orion5x and kirkwood

Albert Aribaud
2010-08-27T00:55:31Z

This rewrite of the mvtwsi driver is 25% smaller and much
faster and simpler than the previous code.

Signed-off-by: Albert Aribaud <albert.aribaud@free.fr>
---
drivers/i2c/mvtwsi.c | 748 +++++++++++++++++++++++---------------------------
1 files changed, 341 insertions(+), 407 deletions(-)

diff --git a/drivers/i2c/mvtwsi.c b/drivers/i2c/mvtwsi.c
index a4409be..456b204 100644
--- a/drivers/i2c/mvtwsi.c
+++ b/drivers/i2c/mvtwsi.c
@@ -1,10 +1,7 @@
/*
- * Driver for the i2c controller on the Marvell line of host bridges
- * (e.g, gt642[46]0, mv643[46]0, mv644[46]0, Orion SoC family),
- * and Kirkwood family.
+ * Driver for the TWSI (i2c) controller on the Marvell orion5x
*
- * Based on:
- * Author: Mark A. Greer <mgreer@mvista.com>
+ * Author: Albert Aribaud <albert.aribaud@free.fr>
* 2005 (c) MontaVista, Software, Inc.
*
* See file CREDITS for list of people who contributed to this
@@ -24,473 +21,410 @@
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
- *
- * ported from Linux to u-boot
- * (C) Copyright 2009
- * Heiko Schocher, DENX Software Engineering, hs at denx.de.
*/
+
#include <common.h>
#include <i2c.h>
-#include <asm/arch/kirkwood.h>
#include <asm/errno.h>
#include <asm/io.h>

-DECLARE_GLOBAL_DATA_PTR;
+/*
+ * include a file that will provide CONFIG_I2C_MVTWSI_BASE
+ * and possibly other settings
+ */

-static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = 0;
-#if defined(CONFIG_I2C_MUX)
-static unsigned int i2c_bus_num_mux __attribute__ ((section ("data"))) = 0;
+#if defined(CONFIG_ORION5X)
+#include <asm/arch/orion5x.h>
+#else
+#error Driver mvtwsi not supported by SoC or board
#endif

-/* Register defines */
-#define KW_I2C_REG_SLAVE_ADDR 0x00
-#define KW_I2C_REG_DATA 0x04
-#define KW_I2C_REG_CONTROL 0x08
-#define KW_I2C_REG_STATUS 0x0c
-#define KW_I2C_REG_BAUD 0x0c
-#define KW_I2C_REG_EXT_SLAVE_ADDR 0x10
-#define KW_I2C_REG_SOFT_RESET 0x1c
-
-#define KW_I2C_REG_CONTROL_ACK 0x00000004
-#define KW_I2C_REG_CONTROL_IFLG 0x00000008
-#define KW_I2C_REG_CONTROL_STOP 0x00000010
-#define KW_I2C_REG_CONTROL_START 0x00000020
-#define KW_I2C_REG_CONTROL_TWSIEN 0x00000040
-#define KW_I2C_REG_CONTROL_INTEN 0x00000080
-
-/* Ctlr status values */
-#define KW_I2C_STATUS_BUS_ERR 0x00
-#define KW_I2C_STATUS_MAST_START 0x08
-#define KW_I2C_STATUS_MAST_REPEAT_START 0x10
-#define KW_I2C_STATUS_MAST_WR_ADDR_ACK 0x18
-#define KW_I2C_STATUS_MAST_WR_ADDR_NO_ACK 0x20
-#define KW_I2C_STATUS_MAST_WR_ACK 0x28
-#define KW_I2C_STATUS_MAST_WR_NO_ACK 0x30
-#define KW_I2C_STATUS_MAST_LOST_ARB 0x38
-#define KW_I2C_STATUS_MAST_RD_ADDR_ACK 0x40
-#define KW_I2C_STATUS_MAST_RD_ADDR_NO_ACK 0x48
-#define KW_I2C_STATUS_MAST_RD_DATA_ACK 0x50
-#define KW_I2C_STATUS_MAST_RD_DATA_NO_ACK 0x58
-#define KW_I2C_STATUS_MAST_WR_ADDR_2_ACK 0xd0
-#define KW_I2C_STATUS_MAST_WR_ADDR_2_NO_ACK 0xd8
-#define KW_I2C_STATUS_MAST_RD_ADDR_2_ACK 0xe0
-#define KW_I2C_STATUS_MAST_RD_ADDR_2_NO_ACK 0xe8
-#define KW_I2C_STATUS_NO_STATUS 0xf8
-
-/* Driver states */
-enum {
- KW_I2C_STATE_INVALID,
- KW_I2C_STATE_IDLE,
- KW_I2C_STATE_WAITING_FOR_START_COND,
- KW_I2C_STATE_WAITING_FOR_ADDR_1_ACK,
- KW_I2C_STATE_WAITING_FOR_ADDR_2_ACK,
- KW_I2C_STATE_WAITING_FOR_SLAVE_ACK,
- KW_I2C_STATE_WAITING_FOR_SLAVE_DATA,
-};
+/*
+ * TWSI register structure
+ */

-/* Driver actions */
-enum {
- KW_I2C_ACTION_INVALID,
- KW_I2C_ACTION_CONTINUE,
- KW_I2C_ACTION_SEND_START,
- KW_I2C_ACTION_SEND_ADDR_1,
- KW_I2C_ACTION_SEND_ADDR_2,
- KW_I2C_ACTION_SEND_DATA,
- KW_I2C_ACTION_RCV_DATA,
- KW_I2C_ACTION_RCV_DATA_STOP,
- KW_I2C_ACTION_SEND_STOP,
+struct mvtwsi_registers {
+ u32 slave_address;
+ u32 data;
+ u32 control;
+ union {
+ u32 status; /* when reading */
+ u32 baudrate; /* when writing */
+ };
+ u32 extended_slave_address;
+ u32 reserved[2];
+ u32 soft_reset;
};

-/* defines to get compatible with Linux driver */
-#define IRQ_NONE 0x0
-#define IRQ_HANDLED 0x01
+/*
+ * Control register fields
+ */

-#define I2C_M_TEN 0x01
-#define I2C_M_RD 0x02
-#define I2C_M_REV_DIR_ADDR 0x04;
+#define MVTWSI_CONTROL_ACK 0x00000004
+#define MVTWSI_CONTROL_IFLG 0x00000008
+#define MVTWSI_CONTROL_STOP 0x00000010
+#define MVTWSI_CONTROL_START 0x00000020
+#define MVTWSI_CONTROL_TWSIEN 0x00000040
+#define MVTWSI_CONTROL_INTEN 0x00000080

-struct i2c_msg {
- u32 addr;
- u32 flags;
- u8 *buf;
- u32 len;
-};
+/*
+ * Status register values -- only those expected in normal master
+ * operation on non-10-bit-address devices; whatever status we don't
+ * expect in nominal conditions (bus errors, arbitration losses,
+ * missing ACKs...) we just pass back to the caller as an error
+ * code.
+ */

-struct kirkwood_i2c_data {
- int irq;
- u32 state;
- u32 action;
- u32 aborting;
- u32 cntl_bits;
- void *reg_base;
- u32 reg_base_p;
- u32 reg_size;
- u32 addr1;
- u32 addr2;
- u32 bytes_left;
- u32 byte_posn;
- u32 block;
- int rc;
- u32 freq_m;
- u32 freq_n;
- struct i2c_msg *msg;
-};
+#define MVTWSI_STATUS_START 0x08
+#define MVTWSI_STATUS_REPEATED_START 0x10
+#define MVTWSI_STATUS_ADDR_W_ACK 0x18
+#define MVTWSI_STATUS_DATA_W_ACK 0x28
+#define MVTWSI_STATUS_ADDR_R_ACK 0x40
+#define MVTWSI_STATUS_ADDR_R_NAK 0x48
+#define MVTWSI_STATUS_DATA_R_ACK 0x50
+#define MVTWSI_STATUS_DATA_R_NAK 0x58
+#define MVTWSI_STATUS_IDLE 0xF8

-static struct kirkwood_i2c_data __drv_data __attribute__ ((section (".data")));
-static struct kirkwood_i2c_data *drv_data = &__drv_data;
-static struct i2c_msg __i2c_msg __attribute__ ((section (".data")));
-static struct i2c_msg *kirkwood_i2c_msg = &__i2c_msg;
+/*
+ * The single instance of the controller we'll be dealing with
+ */
+
+static struct mvtwsi_registers *twsi =
+ (struct mvtwsi_registers *) CONFIG_I2C_MVTWSI_BASE;

/*
- *****************************************************************************
- *
- * Finite State Machine & Interrupt Routines
- *
- *****************************************************************************
+ * Returned statuses are 0 for success and nonzero otherwise.
+ * Currently, cmd_i2c and cmd_eeprom do not interpret an error status.
+ * Thus to ease debugging, the return status contains some debug info:
+ * - bits 31..24 are an error class: 0x01 is timeout, 0x02 is 'status mismatch'.
+ * - bits 23..16 are the last value of the control register.
+ * - bits 15..8 are the last value of the status register.
+ * - bits 7..0 are the expected value of the status register.
*/

-static inline int abs(int n)
+#define MVTWSI_ERROR_WRONG_STATUS 0x01
+#define MVTWSI_ERROR_TIMEOUT 0x02
+
+#define MVTWSI_ERROR(ec, lc, ls, es) (((ec << 24) & 0xFF000000) | \
+ ((lc << 16) & 0x00FF0000) | ((ls<<8) & 0x0000FF00) | (es & 0xFF))
+
+/*
+ * Wait for IFLG to raise, or return 'timeout'; then if status is as expected,
+ * return 0 (ok) or return 'wrong status'.
+ */
+
+static int twsi_wait(int expected_status)
{
- if(n >= 0)
- return n;
- else
- return n * -1;
+ int control, status;
+ int timeout = 1000;
+
+ do {
+ control = readl(&twsi->control);
+ if (control & MVTWSI_CONTROL_IFLG) {
+ status = readl(&twsi->status);
+ if (status == expected_status)
+ return 0;
+ else
+ return MVTWSI_ERROR(
+ MVTWSI_ERROR_WRONG_STATUS,
+ control, status, expected_status);
+ }
+ udelay(10); /* one clock cycle at 100 kHz */
+ } while (timeout--);
+ status = readl(&twsi->status);
+ return MVTWSI_ERROR(
+ MVTWSI_ERROR_TIMEOUT, control, status, expected_status);
}

-static void kirkwood_calculate_speed(int speed)
-{
- int calcspeed;
- int diff;
- int best_diff = CONFIG_SYS_TCLK;
- int best_speed = 0;
- int m, n;
- int tmp[8] = {2, 4, 8, 16, 32, 64, 128, 256};
+/*
+ * These flags are ORed to any write to the control register
+ * They allow global setting of TWSIEN and ACK.
+ * By default none are set.
+ * twsi_start() sets TWSIEN (in case the controller was disabled)
+ * twsi_recv() sets ACK or resets it depending on expected status.
+ */

- for (n = 0; n < 8; n++) {
- for (m = 0; m < 16; m++) {
- calcspeed = CONFIG_SYS_TCLK / (10 * (m + 1) * tmp[n]);
- diff = abs((speed - calcspeed));
- if ( diff < best_diff) {
- best_diff = diff;
- best_speed = calcspeed;
- drv_data->freq_m = m;
- drv_data->freq_n = n;
- }
- }
- }
+static u8 twsi_control_flags = MVTWSI_CONTROL_TWSIEN;
+
+/*
+ * Assert the START condition, either in a single I2C transaction
+ * or inside back-to-back ones (repeated starts).
+ */
+
+static int twsi_start(int expected_status)
+{
+ /* globally set TWSIEN in case it was not */
+ twsi_control_flags |= MVTWSI_CONTROL_TWSIEN;
+ /* assert START */
+ writel(twsi_control_flags | MVTWSI_CONTROL_START, &twsi->control);
+ /* wait for controller to process START */
+ return twsi_wait(expected_status);
}

-/* Reset hardware and initialize FSM */
-static void
-kirkwood_i2c_hw_init(int speed, int slaveadd)
+/*
+ * Send a byte (i2c address or data).
+ */
+
+static int twsi_send(u8 byte, int expected_status)
{
- drv_data->state = KW_I2C_STATE_IDLE;
-
- kirkwood_calculate_speed(speed);
- writel(0, CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_SOFT_RESET);
- writel((((drv_data->freq_m & 0xf) << 3) | (drv_data->freq_n & 0x7)),
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_BAUD);
- writel(slaveadd, CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_SLAVE_ADDR);
- writel(0, CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_EXT_SLAVE_ADDR);
- writel(KW_I2C_REG_CONTROL_TWSIEN | KW_I2C_REG_CONTROL_STOP,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
+ /* put byte in data register for sending */
+ writel(byte, &twsi->data);
+ /* clear any pending interrupt -- that'll cause sending */
+ writel(twsi_control_flags, &twsi->control);
+ /* wait for controller to receive byte and check ACK */
+ return twsi_wait(expected_status);
}

-static void
-kirkwood_i2c_fsm(u32 status)
+/*
+ * Receive a byte.
+ * Global mvtwsi_control_flags variable says if we should ack or nak.
+ */
+
+static int twsi_recv(u8 *byte)
{
- /*
- * If state is idle, then this is likely the remnants of an old
- * operation that driver has given up on or the user has killed.
- * If so, issue the stop condition and go to idle.
- */
- if (drv_data->state == KW_I2C_STATE_IDLE) {
- drv_data->action = KW_I2C_ACTION_SEND_STOP;
- return;
- }
+ int expected_status, status;

- /* The status from the ctlr [mostly] tells us what to do next */
- switch (status) {
- /* Start condition interrupt */
- case KW_I2C_STATUS_MAST_START: /* 0x08 */
- case KW_I2C_STATUS_MAST_REPEAT_START: /* 0x10 */
- drv_data->action = KW_I2C_ACTION_SEND_ADDR_1;
- drv_data->state = KW_I2C_STATE_WAITING_FOR_ADDR_1_ACK;
- break;
-
- /* Performing a write */
- case KW_I2C_STATUS_MAST_WR_ADDR_ACK: /* 0x18 */
- if (drv_data->msg->flags & I2C_M_TEN) {
- drv_data->action = KW_I2C_ACTION_SEND_ADDR_2;
- drv_data->state =
- KW_I2C_STATE_WAITING_FOR_ADDR_2_ACK;
- break;
- }
- /* FALLTHRU */
- case KW_I2C_STATUS_MAST_WR_ADDR_2_ACK: /* 0xd0 */
- case KW_I2C_STATUS_MAST_WR_ACK: /* 0x28 */
- if ((drv_data->bytes_left == 0)
- || (drv_data->aborting
- && (drv_data->byte_posn != 0))) {
- drv_data->action = KW_I2C_ACTION_SEND_STOP;
- drv_data->state = KW_I2C_STATE_IDLE;
- } else {
- drv_data->action = KW_I2C_ACTION_SEND_DATA;
- drv_data->state =
- KW_I2C_STATE_WAITING_FOR_SLAVE_ACK;
- drv_data->bytes_left--;
- }
- break;
-
- /* Performing a read */
- case KW_I2C_STATUS_MAST_RD_ADDR_ACK: /* 40 */
- if (drv_data->msg->flags & I2C_M_TEN) {
- drv_data->action = KW_I2C_ACTION_SEND_ADDR_2;
- drv_data->state =
- KW_I2C_STATE_WAITING_FOR_ADDR_2_ACK;
- break;
- }
- /* FALLTHRU */
- case KW_I2C_STATUS_MAST_RD_ADDR_2_ACK: /* 0xe0 */
- if (drv_data->bytes_left == 0) {
- drv_data->action = KW_I2C_ACTION_SEND_STOP;
- drv_data->state = KW_I2C_STATE_IDLE;
- break;
- }
- /* FALLTHRU */
- case KW_I2C_STATUS_MAST_RD_DATA_ACK: /* 0x50 */
- if (status != KW_I2C_STATUS_MAST_RD_DATA_ACK)
- drv_data->action = KW_I2C_ACTION_CONTINUE;
- else {
- drv_data->action = KW_I2C_ACTION_RCV_DATA;
- drv_data->bytes_left--;
- }
- drv_data->state = KW_I2C_STATE_WAITING_FOR_SLAVE_DATA;
-
- if ((drv_data->bytes_left == 1) || drv_data->aborting)
- drv_data->cntl_bits &= ~KW_I2C_REG_CONTROL_ACK;
- break;
-
- case KW_I2C_STATUS_MAST_RD_DATA_NO_ACK: /* 0x58 */
- drv_data->action = KW_I2C_ACTION_RCV_DATA_STOP;
- drv_data->state = KW_I2C_STATE_IDLE;
- break;
-
- case KW_I2C_STATUS_MAST_WR_ADDR_NO_ACK: /* 0x20 */
- case KW_I2C_STATUS_MAST_WR_NO_ACK: /* 30 */
- case KW_I2C_STATUS_MAST_RD_ADDR_NO_ACK: /* 48 */
- /* Doesn't seem to be a device at other end */
- drv_data->action = KW_I2C_ACTION_SEND_STOP;
- drv_data->state = KW_I2C_STATE_IDLE;
- drv_data->rc = -ENODEV;
- break;
-
- default:
- printf("kirkwood_i2c_fsm: Ctlr Error -- state: 0x%x, "
- "status: 0x%x, addr: 0x%x, flags: 0x%x\n",
- drv_data->state, status, drv_data->msg->addr,
- drv_data->msg->flags);
- drv_data->action = KW_I2C_ACTION_SEND_STOP;
- kirkwood_i2c_hw_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
- drv_data->rc = -EIO;
- }
+ /* compute expected status based on ACK bit in global control flags */
+ if (twsi_control_flags & MVTWSI_CONTROL_ACK)
+ expected_status = MVTWSI_STATUS_DATA_R_ACK;
+ else
+ expected_status = MVTWSI_STATUS_DATA_R_NAK;
+ /* acknowledge *previous state* and launch receive */
+ writel(twsi_control_flags, &twsi->control);
+ /* wait for controller to receive byte and assert ACK or NAK */
+ status = twsi_wait(expected_status);
+ /* if we did receive expected byte then store it */
+ if (status == 0)
+ *byte = readl(&twsi->data);
+ /* return status */
+ return status;
}

-static void
-kirkwood_i2c_do_action(void)
+/*
+ * Assert the STOP condition.
+ * This is also used to force the bus back in idle (SDA=SCL=1).
+ */
+
+static int twsi_stop(int status)
{
- switch(drv_data->action) {
- case KW_I2C_ACTION_CONTINUE:
- writel(drv_data->cntl_bits,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- break;
-
- case KW_I2C_ACTION_SEND_START:
- writel(drv_data->cntl_bits | KW_I2C_REG_CONTROL_START,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- break;
-
- case KW_I2C_ACTION_SEND_ADDR_1:
- writel(drv_data->addr1,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_DATA);
- writel(drv_data->cntl_bits,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- break;
-
- case KW_I2C_ACTION_SEND_ADDR_2:
- writel(drv_data->addr2,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_DATA);
- writel(drv_data->cntl_bits,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- break;
-
- case KW_I2C_ACTION_SEND_DATA:
- writel(drv_data->msg->buf[drv_data->byte_posn++],
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_DATA);
- writel(drv_data->cntl_bits,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- break;
-
- case KW_I2C_ACTION_RCV_DATA:
- drv_data->msg->buf[drv_data->byte_posn++] =
- readl(CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_DATA);
- writel(drv_data->cntl_bits,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- break;
-
- case KW_I2C_ACTION_RCV_DATA_STOP:
- drv_data->msg->buf[drv_data->byte_posn++] =
- readl(CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_DATA);
- drv_data->cntl_bits &= ~KW_I2C_REG_CONTROL_INTEN;
- writel(drv_data->cntl_bits | KW_I2C_REG_CONTROL_STOP,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- drv_data->block = 0;
- break;
-
- case KW_I2C_ACTION_INVALID:
- default:
- printf("kirkwood_i2c_do_action: Invalid action: %d\n",
- drv_data->action);
- drv_data->rc = -EIO;
- /* FALLTHRU */
- case KW_I2C_ACTION_SEND_STOP:
- drv_data->cntl_bits &= ~KW_I2C_REG_CONTROL_INTEN;
- writel(drv_data->cntl_bits | KW_I2C_REG_CONTROL_STOP,
- CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- drv_data->block = 0;
- break;
- }
+ int control, stop_status;
+ int timeout = 1000;
+
+ /* assert STOP */
+ control = MVTWSI_CONTROL_TWSIEN | MVTWSI_CONTROL_STOP;
+ writel(control, &twsi->control);
+ /* wait for IDLE; IFLG won't rise so twsi_wait() is no use. */
+ do {
+ stop_status = readl(&twsi->status);
+ if (stop_status == MVTWSI_STATUS_IDLE)
+ break;
+ udelay(10); /* one clock cycle at 100 kHz */
+ } while (timeout--);
+ control = readl(&twsi->control);
+ if (stop_status != MVTWSI_STATUS_IDLE)
+ if (status == 0)
+ status = MVTWSI_ERROR(
+ MVTWSI_ERROR_TIMEOUT,
+ control, status, MVTWSI_STATUS_IDLE);
+ return status;
}

-static int
-kirkwood_i2c_intr(void)
+/*
+ * Ugly formula to convert m and n values to a frequency comes from
+ * TWSI specifications
+ */
+
+#define TWSI_FREQUENCY(m, n) \
+ ((u8) (CONFIG_SYS_TCLK / (10 * (m + 1) * 2 * (1 << n))))
+
+/*
+ * These are required to be reprogrammed before enabling the controller
+ * because a reset loses them.
+ * Default values come from the spec, but a twsi_reset will change them.
+ * twsi_slave_address left uninitialized lest checkpatch.pl complains.
+ */
+
+static u8 twsi_baud_rate = 0x44;
+static u8 twsi_actual_speed = TWSI_FREQUENCY(4, 4);
+static u8 twsi_slave_address;
+
+/*
+ * Reset controller.
+ * Called@end of i2c_init unsuccessful i2c transactions.
+ * Controller reset also resets the baud rate and slave address, so
+ * re-establish them.
+ */
+
+static void twsi_reset(void)
{
- u32 status;
- u32 ctrl;
- int rc = IRQ_NONE;
-
- ctrl = readl(CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- while ((ctrl & KW_I2C_REG_CONTROL_IFLG) &&
- (drv_data->rc == 0)) {
- status = readl(CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_STATUS);
- kirkwood_i2c_fsm(status);
- kirkwood_i2c_do_action();
- rc = IRQ_HANDLED;
- ctrl = readl(CONFIG_I2C_KW_REG_BASE + KW_I2C_REG_CONTROL);
- udelay(1000);
- }
- return rc;
+ /* ensure controller will be enabled by any twsi*() function */
+ twsi_control_flags = MVTWSI_CONTROL_TWSIEN;
+ /* reset controller */
+ writel(0, &twsi->soft_reset);
+ /* wait 2 ms -- this is what the Marvell LSP does */
+ udelay(20000);
+ /* set baud rate */
+ writel(twsi_baud_rate, &twsi->baudrate);
+ /* set slave address even though we don't use it */
+ writel(twsi_slave_address, &twsi->slave_address);
+ writel(0, &twsi->extended_slave_address);
+ /* assert STOP but don't care for the result */
+ (void) twsi_stop(0);
}

-static void
-kirkwood_i2c_doio(struct i2c_msg *msg)
+/*
+ * I2C init called by cmd_i2c when doing 'i2c reset'.
+ * Sets baud to the highest possible value not exceeding requested one.
+ */
+
+void i2c_init(int requested_speed, int slaveadd)
{
- int ret;
+ int tmp_speed, highest_speed, n, m;
+ int baud = 0x44; /* value at controller reset */

- while ((drv_data->rc == 0) && (drv_data->state != KW_I2C_STATE_IDLE)) {
- /* poll Status register */
- ret = kirkwood_i2c_intr();
- if (ret == IRQ_NONE)
- udelay(10);
+ /* use actual speed to collect progressively higher values */
+ highest_speed = 0;
+ /* compute m, n setting for highest speed not above requested speed */
+ for (n = 0; n < 8; n++) {
+ for (m = 0; m < 16; m++) {
+ tmp_speed = TWSI_FREQUENCY(m, n);
+ if ((tmp_speed <= requested_speed)
+ && (tmp_speed > highest_speed)) {
+ highest_speed = tmp_speed;
+ baud = (m << 3) | n;
+ }
+ }
}
+ /* save baud rate and slave for later calls to twsi_reset */
+ twsi_baud_rate = baud;
+ twsi_actual_speed = highest_speed;
+ twsi_slave_address = slaveadd;
+ /* reset controller */
+ twsi_reset();
}

-static void
-kirkwood_i2c_prepare_for_io(struct i2c_msg *msg)
-{
- u32 dir = 0;
-
- drv_data->msg = msg;
- drv_data->byte_posn = 0;
- drv_data->bytes_left = msg->len;
- drv_data->aborting = 0;
- drv_data->rc = 0;
- /* in u-boot we use no IRQs */
- drv_data->cntl_bits = KW_I2C_REG_CONTROL_ACK | KW_I2C_REG_CONTROL_TWSIEN;
-
- if (msg->flags & I2C_M_RD)
- dir = 1;
- if (msg->flags & I2C_M_TEN) {
- drv_data->addr1 = 0xf0 | (((u32)msg->addr & 0x300) >> 7) | dir;
- drv_data->addr2 = (u32)msg->addr & 0xff;
- } else {
- drv_data->addr1 = ((u32)msg->addr & 0x7f) << 1 | dir;
- drv_data->addr2 = 0;
- }
- /* OK, no start it (from kirkwood_i2c_execute_msg())*/
- drv_data->action = KW_I2C_ACTION_SEND_START;
- drv_data->state = KW_I2C_STATE_WAITING_FOR_START_COND;
- drv_data->block = 1;
- kirkwood_i2c_do_action();
-}
+/*
+ * Begin I2C transaction with expected start status, at given address.
+ * Common to i2c_probe, i2c_read and i2c_write.
+ * Expected address status will derive from direction bit (bit 0) in addr.
+ */

-void
-i2c_init(int speed, int slaveadd)
+static int i2c_begin(int expected_start_status, u8 addr)
{
- kirkwood_i2c_hw_init(speed, slaveadd);
+ int status, expected_addr_status;
+
+ /* compute expected address status from direction bit in addr */
+ if (addr & 1) /* reading */
+ expected_addr_status = MVTWSI_STATUS_ADDR_R_ACK;
+ else /* writing */
+ expected_addr_status = MVTWSI_STATUS_ADDR_W_ACK;
+ /* assert START */
+ status = twsi_start(expected_start_status);
+ /* send out the address if the start went well */
+ if (status == 0)
+ status = twsi_send(addr, expected_addr_status);
+ /* return ok or status of first failure to caller */
+ return status;
}

-int
-i2c_read(u8 dev, uint addr, int alen, u8 *data, int length)
+/*
+ * I2C probe called by cmd_i2c when doing 'i2c probe'.
+ * Begin read, nak data byte, end.
+ */
+
+int i2c_probe(uchar chip)
{
- kirkwood_i2c_msg->buf = data;
- kirkwood_i2c_msg->len = length;
- kirkwood_i2c_msg->addr = dev;
- kirkwood_i2c_msg->flags = I2C_M_RD;
-
- kirkwood_i2c_prepare_for_io(kirkwood_i2c_msg);
- kirkwood_i2c_doio(kirkwood_i2c_msg);
- return drv_data->rc;
+ u8 dummy_byte;
+ int status;
+
+ /* begin i2c read */
+ status = i2c_begin(MVTWSI_STATUS_START, (chip << 1) | 1);
+ /* dummy read was accepted: receive byte but NAK it. */
+ if (status == 0)
+ status = twsi_recv(&dummy_byte);
+ /* Stop transaction */
+ twsi_stop(0);
+ /* return 0 or status of first failure */
+ return status;
}

-int
-i2c_write(u8 dev, uint addr, int alen, u8 *data, int length)
+/*
+ * I2C read called by cmd_i2c when doing 'i2c read' and by cmd_eeprom.c
+ * Begin write, send address byte(s), begin read, receive data bytes, end.
+ *
+ * NOTE: some EEPROMS want a stop right before the second start, while
+ * some will choke if it is there. Deciding which we should do is eeprom
+ * stuff, not i2c, but@the moment the APIs won't let us put it in
+ * cmd_eeprom, so we have to choose here, and for the moment that'll be
+ * a repeated start without a preceding stop.
+ */
+
+int i2c_read(u8 dev, uint addr, int alen, u8 *data, int length)
{
- kirkwood_i2c_msg->buf = data;
- kirkwood_i2c_msg->len = length;
- kirkwood_i2c_msg->addr = dev;
- kirkwood_i2c_msg->flags = 0;
-
- kirkwood_i2c_prepare_for_io(kirkwood_i2c_msg);
- kirkwood_i2c_doio(kirkwood_i2c_msg);
- return drv_data->rc;
+ int status;
+
+ /* begin i2c write to send the address bytes */
+ status = i2c_begin(MVTWSI_STATUS_START, (dev << 1));
+ /* send addr bytes */
+ while ((status == 0) && alen--)
+ status = twsi_send(addr >> (8*alen), MVTWSI_STATUS_DATA_W_ACK);
+ /* begin i2c read to receive eeprom data bytes */
+ if (status == 0)
+ status = i2c_begin(
+ MVTWSI_STATUS_REPEATED_START, (dev << 1) | 1);
+ /* prepare ACK if@least one byte must be received */
+ if (length > 0)
+ twsi_control_flags |= MVTWSI_CONTROL_ACK;
+ /* now receive actual bytes */
+ while ((status == 0) && length--) {
+ /* reset NAK if we if no more to read now */
+ if (length == 0)
+ twsi_control_flags &= ~MVTWSI_CONTROL_ACK;
+ /* read current byte */
+ status = twsi_recv(data++);
+ }
+ /* Stop transaction */
+ status = twsi_stop(status);
+ /* return 0 or status of first failure */
+ return status;
}

-int
-i2c_probe(uchar chip)
+/*
+ * I2C write called by cmd_i2c when doing 'i2c write' and by cmd_eeprom.c
+ * Begin write, send address byte(s), send data bytes, end.
+ */
+
+int i2c_write(u8 dev, uint addr, int alen, u8 *data, int length)
{
- return i2c_read(chip, 0, 0, NULL, 0);
+ int status;
+
+ /* begin i2c write to send the eeprom adress bytes then data bytes */
+ status = i2c_begin(MVTWSI_STATUS_START, (dev << 1));
+ /* send addr bytes */
+ while ((status == 0) && alen--)
+ status = twsi_send(addr >> (8*alen), MVTWSI_STATUS_DATA_W_ACK);
+ /* send data bytes */
+ while ((status == 0) && (length-- > 0))
+ status = twsi_send(*(data++), MVTWSI_STATUS_DATA_W_ACK);
+ /* Stop transaction */
+ status = twsi_stop(status);
+ /* return 0 or status of first failure */
+ return status;
}

+/*
+ * Bus set/get routines: we only support bus 0.
+ */
+
int i2c_set_bus_num(unsigned int bus)
{
-#if defined(CONFIG_I2C_MUX)
- if (bus < CONFIG_SYS_MAX_I2C_BUS) {
- i2c_bus_num = bus;
- } else {
- int ret;
-
- ret = i2x_mux_select_mux(bus);
- if (ret)
- return ret;
- i2c_bus_num = 0;
- }
- i2c_bus_num_mux = bus;
-#else
if (bus > 0) {
return -1;
}
-
- i2c_bus_num = bus;
-#endif
return 0;
}

unsigned int i2c_get_bus_num(void)
{
-#if defined(CONFIG_I2C_MUX)
- return i2c_bus_num_mux;
-#else
- return i2c_bus_num;
-#endif
+ return 0;
}
--
1.7.1