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Message-ID: <1539858268-9648-1-git-send-email-j-keerthy@ti.com>
Date: Thu, 18 Oct 2018 15:54:28 +0530
From: Keerthy <j-keerthy@...com>
To: <aaro.koskinen@....fi>, <tony@...mide.com>
CC: <linux-omap@...r.kernel.org>, <linux-i2c@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <vigneshr@...com>,
<t-kristo@...com>, <j-keerthy@...com>
Subject: [RFC PATCH] i2c: busses: omap: Add the master_xfer_irqless hook
From: Tero Kristo <t-kristo@...com>
Add the master_xfer_irqless hook to enable i2c transactions
in irq disabled contexts like the poweroff case.
Signed-off-by: Tero Kristo <t-kristo@...com>
Signed-off-by: Keerthy <j-keerthy@...com>
---
This is based on Wolfam's series:
https://www.spinics.net/lists/linux-renesas-soc/msg33215.html
Tested on AM572X-IDK for poweroff
drivers/i2c/busses/i2c-omap.c | 79 ++++++++++++++++++++++++++++++++++++-------
1 file changed, 66 insertions(+), 13 deletions(-)
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index b1086bf..1fe4b17 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -269,6 +269,8 @@ struct omap_i2c_dev {
[OMAP_I2C_IP_V2_IRQENABLE_CLR] = 0x30,
};
+static int omap_i2c_xfer_data(struct omap_i2c_dev *omap);
+
static inline void omap_i2c_write_reg(struct omap_i2c_dev *omap,
int reg, u16 val)
{
@@ -648,15 +650,28 @@ static void omap_i2c_resize_fifo(struct omap_i2c_dev *omap, u8 size, bool is_rx)
(1000 * omap->speed / 8);
}
+static void omap_i2c_wait(struct omap_i2c_dev *omap)
+{
+ u16 stat;
+ u16 mask = omap_i2c_read_reg(omap, OMAP_I2C_IE_REG);
+ int count = 0;
+
+ do {
+ stat = omap_i2c_read_reg(omap, OMAP_I2C_STAT_REG);
+ count++;
+ } while (!(stat & mask) && count < 5);
+}
+
/*
* Low level master read/write transaction.
*/
static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
- struct i2c_msg *msg, int stop)
+ struct i2c_msg *msg, int stop, bool polling)
{
struct omap_i2c_dev *omap = i2c_get_adapdata(adap);
unsigned long timeout;
u16 w;
+ int ret;
dev_dbg(omap->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
msg->addr, msg->len, msg->flags, stop);
@@ -680,7 +695,8 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;
omap_i2c_write_reg(omap, OMAP_I2C_BUF_REG, w);
- reinit_completion(&omap->cmd_complete);
+ if (!polling)
+ reinit_completion(&omap->cmd_complete);
omap->cmd_err = 0;
w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
@@ -732,8 +748,21 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
* REVISIT: We should abort the transfer on signals, but the bus goes
* into arbitration and we're currently unable to recover from it.
*/
- timeout = wait_for_completion_timeout(&omap->cmd_complete,
- OMAP_I2C_TIMEOUT);
+ if (!polling) {
+ timeout = wait_for_completion_timeout(&omap->cmd_complete,
+ OMAP_I2C_TIMEOUT);
+ } else {
+ do {
+ omap_i2c_wait(omap);
+ ret = omap_i2c_xfer_data(omap);
+ } while (ret == -EAGAIN);
+
+ if (!ret)
+ timeout = 1;
+ else
+ timeout = 0;
+ }
+
if (timeout == 0) {
dev_err(omap->dev, "controller timed out\n");
omap_i2c_reset(omap);
@@ -772,7 +801,8 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
* to do the work during IRQ processing.
*/
static int
-omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+omap_i2c_xfer_common(struct i2c_adapter *adap, struct i2c_msg msgs[], int num,
+ bool polling)
{
struct omap_i2c_dev *omap = i2c_get_adapdata(adap);
int i;
@@ -794,7 +824,8 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
omap->set_mpu_wkup_lat(omap->dev, omap->latency);
for (i = 0; i < num; i++) {
- r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
+ r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)),
+ polling);
if (r != 0)
break;
}
@@ -813,6 +844,18 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
return r;
}
+static int
+omap_i2c_xfer_irq(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+ return omap_i2c_xfer_common(adap, msgs, num, false);
+}
+
+static int
+omap_i2c_xfer_polling(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+ return omap_i2c_xfer_common(adap, msgs, num, true);
+}
+
static u32
omap_i2c_func(struct i2c_adapter *adap)
{
@@ -1035,10 +1078,8 @@ static int omap_i2c_transmit_data(struct omap_i2c_dev *omap, u8 num_bytes,
return ret;
}
-static irqreturn_t
-omap_i2c_isr_thread(int this_irq, void *dev_id)
+static int omap_i2c_xfer_data(struct omap_i2c_dev *omap)
{
- struct omap_i2c_dev *omap = dev_id;
u16 bits;
u16 stat;
int err = 0, count = 0;
@@ -1056,7 +1097,8 @@ static int omap_i2c_transmit_data(struct omap_i2c_dev *omap, u8 num_bytes,
if (!stat) {
/* my work here is done */
- goto out;
+ err = -EAGAIN;
+ break;
}
dev_dbg(omap->dev, "IRQ (ISR = 0x%04x)\n", stat);
@@ -1165,14 +1207,25 @@ static int omap_i2c_transmit_data(struct omap_i2c_dev *omap, u8 num_bytes,
}
} while (stat);
- omap_i2c_complete_cmd(omap, err);
+ return err;
+}
+
+static irqreturn_t
+omap_i2c_isr_thread(int this_irq, void *dev_id)
+{
+ int ret;
+ struct omap_i2c_dev *omap = dev_id;
+
+ ret = omap_i2c_xfer_data(omap);
+ if (ret != -EAGAIN)
+ omap_i2c_complete_cmd(omap, ret);
-out:
return IRQ_HANDLED;
}
static const struct i2c_algorithm omap_i2c_algo = {
- .master_xfer = omap_i2c_xfer,
+ .master_xfer = omap_i2c_xfer_irq,
+ .master_xfer_irqless = omap_i2c_xfer_polling,
.functionality = omap_i2c_func,
};
--
1.9.1
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