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path: root/drivers/i2c/busses/i2c-sh_mobile.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-sh_mobile.c')
-rw-r--r--drivers/i2c/busses/i2c-sh_mobile.c271
1 files changed, 208 insertions, 63 deletions
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 840e634fa31..640cbb23732 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -31,13 +31,84 @@
#include <linux/clk.h>
#include <linux/io.h>
+/* Transmit operation: */
+/* */
+/* 0 byte transmit */
+/* BUS: S A8 ACK P */
+/* IRQ: DTE WAIT */
+/* ICIC: */
+/* ICCR: 0x94 0x90 */
+/* ICDR: A8 */
+/* */
+/* 1 byte transmit */
+/* BUS: S A8 ACK D8(1) ACK P */
+/* IRQ: DTE WAIT WAIT */
+/* ICIC: -DTE */
+/* ICCR: 0x94 0x90 */
+/* ICDR: A8 D8(1) */
+/* */
+/* 2 byte transmit */
+/* BUS: S A8 ACK D8(1) ACK D8(2) ACK P */
+/* IRQ: DTE WAIT WAIT WAIT */
+/* ICIC: -DTE */
+/* ICCR: 0x94 0x90 */
+/* ICDR: A8 D8(1) D8(2) */
+/* */
+/* 3 bytes or more, +---------+ gets repeated */
+/* */
+/* */
+/* Receive operation: */
+/* */
+/* 0 byte receive - not supported since slave may hold SDA low */
+/* */
+/* 1 byte receive [TX] | [RX] */
+/* BUS: S A8 ACK | D8(1) ACK P */
+/* IRQ: DTE WAIT | WAIT DTE */
+/* ICIC: -DTE | +DTE */
+/* ICCR: 0x94 0x81 | 0xc0 */
+/* ICDR: A8 | D8(1) */
+/* */
+/* 2 byte receive [TX]| [RX] */
+/* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P */
+/* IRQ: DTE WAIT | WAIT WAIT DTE */
+/* ICIC: -DTE | +DTE */
+/* ICCR: 0x94 0x81 | 0xc0 */
+/* ICDR: A8 | D8(1) D8(2) */
+/* */
+/* 3 byte receive [TX] | [RX] */
+/* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */
+/* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */
+/* ICIC: -DTE | +DTE */
+/* ICCR: 0x94 0x81 | 0xc0 */
+/* ICDR: A8 | D8(1) D8(2) D8(3) */
+/* */
+/* 4 bytes or more, this part is repeated +---------+ */
+/* */
+/* */
+/* Interrupt order and BUSY flag */
+/* ___ _ */
+/* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
+/* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
+/* */
+/* S D7 D6 D5 D4 D3 D2 D1 D0 P */
+/* ___ */
+/* WAIT IRQ ________________________________/ \___________ */
+/* TACK IRQ ____________________________________/ \_______ */
+/* DTE IRQ __________________________________________/ \_ */
+/* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
+/* _______________________________________________ */
+/* BUSY __/ \_ */
+/* */
+
enum sh_mobile_i2c_op {
OP_START = 0,
- OP_TX_ONLY,
+ OP_TX_FIRST,
+ OP_TX,
OP_TX_STOP,
OP_TX_TO_RX,
- OP_RX_ONLY,
+ OP_RX,
OP_RX_STOP,
+ OP_RX_STOP_DATA,
};
struct sh_mobile_i2c_data {
@@ -127,25 +198,34 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
spin_lock_irqsave(&pd->lock, flags);
switch (op) {
- case OP_START:
+ case OP_START: /* issue start and trigger DTE interrupt */
iowrite8(0x94, ICCR(pd));
break;
- case OP_TX_ONLY:
+ case OP_TX_FIRST: /* disable DTE interrupt and write data */
+ iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE, ICIC(pd));
iowrite8(data, ICDR(pd));
break;
- case OP_TX_STOP:
+ case OP_TX: /* write data */
iowrite8(data, ICDR(pd));
- iowrite8(0x90, ICCR(pd));
- iowrite8(ICIC_ALE | ICIC_TACKE, ICIC(pd));
break;
- case OP_TX_TO_RX:
+ case OP_TX_STOP: /* write data and issue a stop afterwards */
iowrite8(data, ICDR(pd));
+ iowrite8(0x90, ICCR(pd));
+ break;
+ case OP_TX_TO_RX: /* select read mode */
iowrite8(0x81, ICCR(pd));
break;
- case OP_RX_ONLY:
+ case OP_RX: /* just read data */
ret = ioread8(ICDR(pd));
break;
- case OP_RX_STOP:
+ case OP_RX_STOP: /* enable DTE interrupt, issue stop */
+ iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
+ ICIC(pd));
+ iowrite8(0xc0, ICCR(pd));
+ break;
+ case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
+ iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
+ ICIC(pd));
ret = ioread8(ICDR(pd));
iowrite8(0xc0, ICCR(pd));
break;
@@ -157,58 +237,120 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
return ret;
}
+static int sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
+{
+ if (pd->pos == -1)
+ return 1;
+
+ return 0;
+}
+
+static int sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
+{
+ if (pd->pos == (pd->msg->len - 1))
+ return 1;
+
+ return 0;
+}
+
+static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
+ unsigned char *buf)
+{
+ switch (pd->pos) {
+ case -1:
+ *buf = (pd->msg->addr & 0x7f) << 1;
+ *buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
+ break;
+ default:
+ *buf = pd->msg->buf[pd->pos];
+ }
+}
+
+static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
+{
+ unsigned char data;
+
+ if (pd->pos == pd->msg->len)
+ return 1;
+
+ sh_mobile_i2c_get_data(pd, &data);
+
+ if (sh_mobile_i2c_is_last_byte(pd))
+ i2c_op(pd, OP_TX_STOP, data);
+ else if (sh_mobile_i2c_is_first_byte(pd))
+ i2c_op(pd, OP_TX_FIRST, data);
+ else
+ i2c_op(pd, OP_TX, data);
+
+ pd->pos++;
+ return 0;
+}
+
+static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
+{
+ unsigned char data;
+ int real_pos;
+
+ do {
+ if (pd->pos <= -1) {
+ sh_mobile_i2c_get_data(pd, &data);
+
+ if (sh_mobile_i2c_is_first_byte(pd))
+ i2c_op(pd, OP_TX_FIRST, data);
+ else
+ i2c_op(pd, OP_TX, data);
+ break;
+ }
+
+ if (pd->pos == 0) {
+ i2c_op(pd, OP_TX_TO_RX, 0);
+ break;
+ }
+
+ real_pos = pd->pos - 2;
+
+ if (pd->pos == pd->msg->len) {
+ if (real_pos < 0) {
+ i2c_op(pd, OP_RX_STOP, 0);
+ break;
+ }
+ data = i2c_op(pd, OP_RX_STOP_DATA, 0);
+ } else
+ data = i2c_op(pd, OP_RX, 0);
+
+ pd->msg->buf[real_pos] = data;
+ } while (0);
+
+ pd->pos++;
+ return pd->pos == (pd->msg->len + 2);
+}
+
static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
{
struct platform_device *dev = dev_id;
struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
- struct i2c_msg *msg = pd->msg;
- unsigned char data, sr;
- int wakeup = 0;
+ unsigned char sr;
+ int wakeup;
sr = ioread8(ICSR(pd));
- pd->sr |= sr;
+ pd->sr |= sr; /* remember state */
dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
- (msg->flags & I2C_M_RD) ? "read" : "write",
- pd->pos, msg->len);
+ (pd->msg->flags & I2C_M_RD) ? "read" : "write",
+ pd->pos, pd->msg->len);
if (sr & (ICSR_AL | ICSR_TACK)) {
- iowrite8(0, ICIC(pd)); /* disable interrupts */
- wakeup = 1;
- goto do_wakeup;
- }
+ /* don't interrupt transaction - continue to issue stop */
+ iowrite8(sr & ~(ICSR_AL | ICSR_TACK), ICSR(pd));
+ wakeup = 0;
+ } else if (pd->msg->flags & I2C_M_RD)
+ wakeup = sh_mobile_i2c_isr_rx(pd);
+ else
+ wakeup = sh_mobile_i2c_isr_tx(pd);
- if (pd->pos == msg->len) {
- i2c_op(pd, OP_RX_ONLY, 0);
- wakeup = 1;
- goto do_wakeup;
- }
+ if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
+ iowrite8(sr & ~ICSR_WAIT, ICSR(pd));
- if (pd->pos == -1) {
- data = (msg->addr & 0x7f) << 1;
- data |= (msg->flags & I2C_M_RD) ? 1 : 0;
- } else
- data = msg->buf[pd->pos];
-
- if ((pd->pos == -1) || !(msg->flags & I2C_M_RD)) {
- if (msg->flags & I2C_M_RD)
- i2c_op(pd, OP_TX_TO_RX, data);
- else if (pd->pos == (msg->len - 1)) {
- i2c_op(pd, OP_TX_STOP, data);
- wakeup = 1;
- } else
- i2c_op(pd, OP_TX_ONLY, data);
- } else {
- if (pd->pos == (msg->len - 1))
- data = i2c_op(pd, OP_RX_STOP, 0);
- else
- data = i2c_op(pd, OP_RX_ONLY, 0);
-
- msg->buf[pd->pos] = data;
- }
- pd->pos++;
-
- do_wakeup:
if (wakeup) {
pd->sr |= SW_DONE;
wake_up(&pd->wait);
@@ -219,6 +361,11 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
{
+ if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
+ dev_err(pd->dev, "Unsupported zero length i2c read\n");
+ return -EIO;
+ }
+
/* Initialize channel registers */
iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
@@ -233,9 +380,8 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
pd->pos = -1;
pd->sr = 0;
- /* Enable all interrupts except wait */
- iowrite8(ioread8(ICIC(pd)) | ICIC_ALE | ICIC_TACKE | ICIC_DTEE,
- ICIC(pd));
+ /* Enable all interrupts to begin with */
+ iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, ICIC(pd));
return 0;
}
@@ -268,25 +414,18 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
if (!k)
dev_err(pd->dev, "Transfer request timed out\n");
- retry_count = 10;
+ retry_count = 1000;
again:
val = ioread8(ICSR(pd));
dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
- if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
- err = -EIO;
- break;
- }
-
/* the interrupt handler may wake us up before the
* transfer is finished, so poll the hardware
* until we're done.
*/
-
- if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) &&
- (val & ICSR_SDAM))) {
- msleep(1);
+ if (val & ICSR_BUSY) {
+ udelay(10);
if (retry_count--)
goto again;
@@ -294,6 +433,12 @@ again:
dev_err(pd->dev, "Polling timed out\n");
break;
}
+
+ /* handle missing acknowledge and arbitration lost */
+ if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
+ err = -EIO;
+ break;
+ }
}
deactivate_ch(pd);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-05 06:40:40 +0000