From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: linux-i2c@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org,
Wolfram Sang <wsa+renesas@sang-engineering.com>
Subject: [PATCH] i2c: rcar: document HW incapabilities
Date: Mon, 19 Jun 2017 23:41:46 +0200 [thread overview]
Message-ID: <20170619214146.4784-1-wsa+renesas@sang-engineering.com> (raw)
Add recent findings (IGNORE_NAK) and document in a bit more detail why
the feature is not possible.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
drivers/i2c/busses/i2c-rcar.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 048deee674955c..93c1a54981df08 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -783,7 +783,12 @@ static int rcar_unreg_slave(struct i2c_client *slave)
static u32 rcar_i2c_func(struct i2c_adapter *adap)
{
- /* This HW can't do SMBUS_QUICK and NOSTART */
+ /*
+ * This HW can't do:
+ * I2C_SMBUS_QUICK (setting FSB during START didn't work)
+ * I2C_M_NOSTART (automatically sends address after START)
+ * I2C_M_IGNORE_NAK (automatically sends STOP after NAK)
+ */
return I2C_FUNC_I2C | I2C_FUNC_SLAVE |
(I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}
--
2.10.2
next reply other threads:[~2017-06-19 21:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-19 21:41 Wolfram Sang [this message]
2017-06-23 18:31 ` [PATCH] i2c: rcar: document HW incapabilities Wolfram Sang
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