From 9528d1c7a541b481a0e80301dc8d545848104023 Mon Sep 17 00:00:00 2001
From: Michael Hennerich <michael.hennerich@analog.com>
Date: Mon, 18 May 2009 08:14:41 -0400
Subject: [PATCH] i2c: Blackfin TWI: make sure we don't end up with a CLKDIV=0
Make sure we don't end up with an invalid CLKDIV=0 in case someone
specifies 20kHz SCL or less (5 * 1024 / 20 = 0x100).
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
[ben-linux@fluff.org: shortened subject line]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
---
drivers/i2c/busses/Kconfig | 2 +-
drivers/i2c/busses/i2c-bfin-twi.c | 11 ++++++++---
2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index f1c6ca7e285235..c8460fa9cfac75 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -298,7 +298,7 @@ config I2C_BLACKFIN_TWI
config I2C_BLACKFIN_TWI_CLK_KHZ
int "Blackfin TWI I2C clock (kHz)"
depends on I2C_BLACKFIN_TWI
- range 10 400
+ range 21 400
default 50
help
The unit of the TWI clock is kHz.
diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c
index fc548b3d002e58..77cafb6ba923c3 100644
--- a/drivers/i2c/busses/i2c-bfin-twi.c
+++ b/drivers/i2c/busses/i2c-bfin-twi.c
@@ -614,6 +614,7 @@ static int i2c_bfin_twi_probe(struct platform_device *pdev)
struct i2c_adapter *p_adap;
struct resource *res;
int rc;
+ unsigned int clkhilow;
iface = kzalloc(sizeof(struct bfin_twi_iface), GFP_KERNEL);
if (!iface) {
@@ -675,10 +676,14 @@ static int i2c_bfin_twi_probe(struct platform_device *pdev)
/* Set TWI internal clock as 10MHz */
write_CONTROL(iface, ((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F);
+ /*
+ * We will not end up with a CLKDIV=0 because no one will specify
+ * 20kHz SCL or less in Kconfig now. (5 * 1024 / 20 = 0x100)
+ */
+ clkhilow = 5 * 1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ;
+
/* Set Twi interface clock as specified */
- write_CLKDIV(iface, ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
- << 8) | ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
- & 0xFF));
+ write_CLKDIV(iface, (clkhilow << 8) | clkhilow);
/* Enable TWI */
write_CONTROL(iface, read_CONTROL(iface) | TWI_ENA);
--
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