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Message-Id: <1416326695-13083-4-git-send-email-wsa@the-dreams.de>
Date: Tue, 18 Nov 2014 17:04:55 +0100
From: Wolfram Sang <wsa@...-dreams.de>
To: linux-i2c@...r.kernel.org
Cc: linux-sh@...r.kernel.org, Wolfram Sang <wsa@...-dreams.de>,
Magnus Damm <magnus.damm@...il.com>,
Simon Horman <horms@...ge.net.au>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Jean Delvare <jdelvare@...e.de>
Subject: [PATCH 3/3] i2c: rcar: add slave support
From: Wolfram Sang <wsa+renesas@...g-engineering.com>
The first I2C slave provider using the new generic interface.
Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
---
Changes since RFC:
* no runtime_pm for slaves
* don't use NULL in i2c_slave_event
drivers/i2c/busses/i2c-rcar.c | 125 +++++++++++++++++++++++++++++++++++++++---
1 file changed, 116 insertions(+), 9 deletions(-)
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index d826e82dd997..369ef747fb81 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -48,6 +48,12 @@
#define ICMAR 0x20 /* master address */
#define ICRXTX 0x24 /* data port */
+/* ICSCR */
+#define SDBS (1 << 3) /* slave data buffer select */
+#define SIE (1 << 2) /* slave interface enable */
+#define GCAE (1 << 1) /* general call address enable */
+#define FNA (1 << 0) /* forced non acknowledgement */
+
/* ICMCR */
#define MDBS (1 << 7) /* non-fifo mode switch */
#define FSCL (1 << 6) /* override SCL pin */
@@ -58,6 +64,15 @@
#define FSB (1 << 1) /* force stop bit */
#define ESG (1 << 0) /* en startbit gen */
+/* ICSSR (also for ICSIER) */
+#define GCAR (1 << 6) /* general call received */
+#define STM (1 << 5) /* slave transmit mode */
+#define SSR (1 << 4) /* stop received */
+#define SDE (1 << 3) /* slave data empty */
+#define SDT (1 << 2) /* slave data transmitted */
+#define SDR (1 << 1) /* slave data received */
+#define SAR (1 << 0) /* slave addr received */
+
/* ICMSR (also for ICMIE) */
#define MNR (1 << 6) /* nack received */
#define MAL (1 << 5) /* arbitration lost */
@@ -103,6 +118,7 @@ struct rcar_i2c_priv {
u32 icccr;
u32 flags;
enum rcar_i2c_type devtype;
+ struct i2c_client *slave;
};
#define rcar_i2c_priv_to_dev(p) ((p)->adap.dev.parent)
@@ -126,15 +142,6 @@ static u32 rcar_i2c_read(struct rcar_i2c_priv *priv, int reg)
static void rcar_i2c_init(struct rcar_i2c_priv *priv)
{
- /*
- * reset slave mode.
- * slave mode is not used on this driver
- */
- rcar_i2c_write(priv, ICSIER, 0);
- rcar_i2c_write(priv, ICSAR, 0);
- rcar_i2c_write(priv, ICSCR, 0);
- rcar_i2c_write(priv, ICSSR, 0);
-
/* reset master mode */
rcar_i2c_write(priv, ICMIER, 0);
rcar_i2c_write(priv, ICMCR, 0);
@@ -360,6 +367,63 @@ static int rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
return 0;
}
+static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
+{
+ u32 ssr_raw, ssr_filtered;
+ u8 value;
+
+ ssr_raw = rcar_i2c_read(priv, ICSSR) & 0xff;
+ ssr_filtered = ssr_raw & rcar_i2c_read(priv, ICSIER);
+
+ if (!ssr_filtered)
+ return false;
+
+ /* address detected */
+ if (ssr_filtered & SAR) {
+ /* read or write request */
+ if (ssr_raw & STM) {
+ i2c_slave_event(priv->slave, I2C_SLAVE_REQ_READ_START, &value);
+ rcar_i2c_write(priv, ICRXTX, value);
+ rcar_i2c_write(priv, ICSIER, SDE | SSR | SAR);
+ } else {
+ i2c_slave_event(priv->slave, I2C_SLAVE_REQ_WRITE_START, &value);
+ rcar_i2c_read(priv, ICRXTX); /* dummy read */
+ rcar_i2c_write(priv, ICSIER, SDR | SSR | SAR);
+ }
+
+ rcar_i2c_write(priv, ICSSR, ~SAR & 0xff);
+ }
+
+ /* master sent stop */
+ if (ssr_filtered & SSR) {
+ i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value);
+ rcar_i2c_write(priv, ICSIER, SAR | SSR);
+ rcar_i2c_write(priv, ICSSR, ~SSR & 0xff);
+ }
+
+ /* master wants to write to us */
+ if (ssr_filtered & SDR) {
+ int ret;
+
+ value = rcar_i2c_read(priv, ICRXTX);
+ ret = i2c_slave_event(priv->slave, I2C_SLAVE_REQ_WRITE_END, &value);
+ /* Send NACK in case of error */
+ rcar_i2c_write(priv, ICSCR, SIE | SDBS | (ret < 0 ? FNA : 0));
+ i2c_slave_event(priv->slave, I2C_SLAVE_REQ_WRITE_START, &value);
+ rcar_i2c_write(priv, ICSSR, ~SDR & 0xff);
+ }
+
+ /* master wants to read from us */
+ if (ssr_filtered & SDE) {
+ i2c_slave_event(priv->slave, I2C_SLAVE_REQ_READ_END, &value);
+ i2c_slave_event(priv->slave, I2C_SLAVE_REQ_READ_START, &value);
+ rcar_i2c_write(priv, ICRXTX, value);
+ rcar_i2c_write(priv, ICSSR, ~SDE & 0xff);
+ }
+
+ return true;
+}
+
static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
{
struct rcar_i2c_priv *priv = ptr;
@@ -369,6 +433,9 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
/*-------------- spin lock -----------------*/
spin_lock(&priv->lock);
+ if (rcar_i2c_slave_irq(priv))
+ goto exit;
+
msr = rcar_i2c_read(priv, ICMSR);
/* Only handle interrupts that are currently enabled */
@@ -499,6 +566,44 @@ out:
return ret;
}
+
+static int rcar_reg_slave(struct i2c_client *slave)
+{
+ struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
+
+ if (priv->slave)
+ return -EBUSY;
+
+ if (slave->flags & I2C_CLIENT_TEN)
+ return -EAFNOSUPPORT;
+
+ pm_runtime_forbid(rcar_i2c_priv_to_dev(priv));
+
+ priv->slave = slave;
+ rcar_i2c_write(priv, ICSAR, slave->addr);
+ rcar_i2c_write(priv, ICSSR, 0);
+ rcar_i2c_write(priv, ICSIER, SAR | SSR);
+ rcar_i2c_write(priv, ICSCR, SIE | SDBS);
+
+ return 0;
+}
+
+static int rcar_unreg_slave(struct i2c_client *slave)
+{
+ struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
+
+ WARN_ON(!priv->slave);
+
+ rcar_i2c_write(priv, ICSIER, 0);
+ rcar_i2c_write(priv, ICSCR, 0);
+
+ priv->slave = NULL;
+
+ pm_runtime_allow(rcar_i2c_priv_to_dev(priv));
+
+ return 0;
+}
+
static u32 rcar_i2c_func(struct i2c_adapter *adap)
{
/* This HW can't do SMBUS_QUICK and NOSTART */
@@ -508,6 +613,8 @@ static u32 rcar_i2c_func(struct i2c_adapter *adap)
static const struct i2c_algorithm rcar_i2c_algo = {
.master_xfer = rcar_i2c_master_xfer,
.functionality = rcar_i2c_func,
+ .reg_slave = rcar_reg_slave,
+ .unreg_slave = rcar_unreg_slave,
};
static const struct of_device_id rcar_i2c_dt_ids[] = {
--
2.1.1
--
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