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@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 at 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 at 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 at 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; }