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i2c: rcar: add support for I2C_M_RECV_LEN 

With this feature added, SMBus Block reads and Proc calls are now
supported. This patch is the best of two independent developments by
Wolfram and Bhuvanesh + Andrew, refactored again by Wolfram.

Signed-off-by: Bhuvanesh Surachari <bhuvanesh_surachari@mentor.com>
Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
This commit is contained in:
Wolfram Sang 2022-04-05 12:07:56 +02:00 committed by Wolfram Sang
parent c562570e00
commit 633c0e7559
1 changed files with 27 additions and 4 deletions
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31
drivers/i2c/busses/i2c-rcar.c
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@ -105,6 +105,7 @@
#define ID_DONE (1 << 2)
#define ID_ARBLOST (1 << 3)
#define ID_NACK (1 << 4)
#define ID_EPROTO (1 << 5)
/* persistent flags */
#define ID_P_HOST_NOTIFY BIT(28)
#define ID_P_REP_AFTER_RD BIT(29)
@ -522,6 +523,7 @@ static void rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
static void rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
{
struct i2c_msg *msg = priv->msg;
bool recv_len_init = priv->pos == 0 && msg->flags & I2C_M_RECV_LEN;
/* FIXME: sometimes, unknown interrupt happened. Do nothing */
if (!(msr & MDR))
@ -535,12 +537,29 @@ static void rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
rcar_i2c_dma(priv);
} else if (priv->pos < msg->len) {
/* get received data */
msg->buf[priv->pos] = rcar_i2c_read(priv, ICRXTX);
u8 data = rcar_i2c_read(priv, ICRXTX);
msg->buf[priv->pos] = data;
if (recv_len_init) {
if (data == 0 || data > I2C_SMBUS_BLOCK_MAX) {
priv->flags |= ID_DONE | ID_EPROTO;
return;
}
msg->len += msg->buf[0];
/* Enough data for DMA? */
if (rcar_i2c_dma(priv))
return;
/* new length after RECV_LEN now properly initialized */
recv_len_init = false;
}
priv->pos++;
}
/* If next received data is the _LAST_, go to new phase. */
if (priv->pos + 1 == msg->len) {
/*
* If next received data is the _LAST_ and we are not waiting for a new
* length because of RECV_LEN, then go to a new phase.
*/
if (priv->pos + 1 == msg->len && !recv_len_init) {
if (priv->flags & ID_LAST_MSG) {
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
} else {
@ -847,6 +866,8 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
ret = -ENXIO;
} else if (priv->flags & ID_ARBLOST) {
ret = -EAGAIN;
} else if (priv->flags & ID_EPROTO) {
ret = -EPROTO;
} else {
ret = num - priv->msgs_left; /* The number of transfer */
}
@ -909,6 +930,8 @@ static int rcar_i2c_master_xfer_atomic(struct i2c_adapter *adap,
ret = -ENXIO;
} else if (priv->flags & ID_ARBLOST) {
ret = -EAGAIN;
} else if (priv->flags & ID_EPROTO) {
ret = -EPROTO;
} else {
ret = num - priv->msgs_left; /* The number of transfer */
}
@ -975,7 +998,7 @@ static u32 rcar_i2c_func(struct i2c_adapter *adap)
* I2C_M_IGNORE_NAK (automatically sends STOP after NAK)
*/
u32 func = I2C_FUNC_I2C | I2C_FUNC_SLAVE |
(I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
(I2C_FUNC_SMBUS_EMUL_ALL & ~I2C_FUNC_SMBUS_QUICK);
if (priv->flags & ID_P_HOST_NOTIFY)
func |= I2C_FUNC_SMBUS_HOST_NOTIFY;