From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Babic Date: Sat, 11 Aug 2012 12:37:57 +0200 Subject: [U-Boot] [PATCH] mxc_spi: Round up clock divider In-Reply-To: <1318215291.2281949.1344624710946.JavaMail.root@advansee.com> References: <1318215291.2281949.1344624710946.JavaMail.root@advansee.com> Message-ID: <50263605.1000601@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 10/08/2012 20:51, Beno?t Th?baudeau wrote: > Since the input frequency of the API is a maximum that should not be exceeded in > order for the devices to operate properly, the SPI clock divider should be > rounded up, not truncated. > Hi Beno?t, > Signed-off-by: Beno?t Th?baudeau > Cc: Wolfgang Denk > Cc: Stefano Babic > --- > .../drivers/spi/mxc_spi.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git u-boot-4d3c95f.orig/drivers/spi/mxc_spi.c u-boot-4d3c95f/drivers/spi/mxc_spi.c > index 2e15318..cf1462f 100644 > --- u-boot-4d3c95f.orig/drivers/spi/mxc_spi.c > +++ u-boot-4d3c95f/drivers/spi/mxc_spi.c > @@ -96,7 +96,7 @@ static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs, > > clk_src = mxc_get_clock(MXC_CSPI_CLK); > > - div = clk_src / max_hz; > + div = DIV_ROUND_UP(clk_src, max_hz); > div = get_cspi_div(div); > > debug("clk %d Hz, div %d, real clk %d Hz\n", > @@ -147,7 +147,7 @@ static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs, > * The following computation is taken directly from Freescale's code. > */ > if (clk_src > max_hz) { > - pre_div = clk_src / max_hz; > + pre_div = DIV_ROUND_UP(clk_src, max_hz); > if (pre_div > 16) { > post_div = pre_div / 16; > pre_div = 15; > Agree - do you also get a case where the divider was too low and the SPI does not work or it was only examining the code ? Acked-by: Stefano Babic Best regards, Stefano Babic -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de =====================================================================