From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Frysinger Subject: [PATCH 1/3 v2] Blackfin I2C/TWI Driver: make sure we don't end up with a CLKDIV=0 Date: Mon, 1 Jun 2009 01:37:50 -0400 Message-ID: <1243834670-32610-1-git-send-email-vapier@gentoo.org> References: <20090527070542.GA3085@pengutronix.de> Return-path: In-Reply-To: <20090527070542.GA3085-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: uclinux-dist-devel-ZG0+EudsQA8dtHy/vicBwGD2FQJk+8+b@public.gmane.org, Michael Hennerich , Bryan Wu List-Id: linux-i2c@vger.kernel.org From: Michael Hennerich 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 Signed-off-by: Mike Frysinger Signed-off-by: Bryan Wu --- v2 - fixup comment grammar pointed out by Wolfram Sang 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 7f95905..1fbfd98 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -297,7 +297,7 @@ 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 3c855ff..ea97723 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) { @@ -676,10 +677,14 @@ 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); -- 1.6.3.1