* [U-Boot] [PATCH] mxc_spi: Round up clock divider
[not found] <797579011.2281948.1344624706885.JavaMail.root@advansee.com>
@ 2012-08-10 18:51 ` Benoît Thébaudeau
2012-08-11 10:37 ` Stefano Babic
2012-08-20 7:54 ` Stefano Babic
0 siblings, 2 replies; 4+ messages in thread
From: Benoît Thébaudeau @ 2012-08-10 18:51 UTC (permalink / raw)
To: u-boot
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.
Signed-off-by: Beno?t Th?baudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
---
.../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;
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [U-Boot] [PATCH] mxc_spi: Round up clock divider
2012-08-10 18:51 ` [U-Boot] [PATCH] mxc_spi: Round up clock divider Benoît Thébaudeau
@ 2012-08-11 10:37 ` Stefano Babic
2012-08-11 14:23 ` Benoît Thébaudeau
2012-08-20 7:54 ` Stefano Babic
1 sibling, 1 reply; 4+ messages in thread
From: Stefano Babic @ 2012-08-11 10:37 UTC (permalink / raw)
To: u-boot
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 <benoit.thebaudeau@advansee.com>
> Cc: Wolfgang Denk <wd@denx.de>
> Cc: Stefano Babic <sbabic@denx.de>
> ---
> .../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 <sbabic@denx.de>
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
=====================================================================
^ permalink raw reply [flat|nested] 4+ messages in thread
* [U-Boot] [PATCH] mxc_spi: Round up clock divider
2012-08-11 10:37 ` Stefano Babic
@ 2012-08-11 14:23 ` Benoît Thébaudeau
0 siblings, 0 replies; 4+ messages in thread
From: Benoît Thébaudeau @ 2012-08-11 14:23 UTC (permalink / raw)
To: u-boot
Hi Stefano,
On 08/11/2012 12:37, Stefano Babic wrote:
> 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 <benoit.thebaudeau@advansee.com>
> > Cc: Wolfgang Denk <wd@denx.de>
> > Cc: Stefano Babic <sbabic@denx.de>
> > ---
> > .../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 ?
It was only examining the code. I had many clock issues on i.MX51, so I made a
global review of clock usage that led to that. Most i.MX5 clock functions are
broken. I have a series fixing these that I will post next week.
> Acked-by: Stefano Babic <sbabic@denx.de>
>
> Best regards,
> Stefano Babic
Best regards,
Beno?t
^ permalink raw reply [flat|nested] 4+ messages in thread
* [U-Boot] [PATCH] mxc_spi: Round up clock divider
2012-08-10 18:51 ` [U-Boot] [PATCH] mxc_spi: Round up clock divider Benoît Thébaudeau
2012-08-11 10:37 ` Stefano Babic
@ 2012-08-20 7:54 ` Stefano Babic
1 sibling, 0 replies; 4+ messages in thread
From: Stefano Babic @ 2012-08-20 7:54 UTC (permalink / raw)
To: u-boot
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.
>
> Signed-off-by: Beno?t Th?baudeau <benoit.thebaudeau@advansee.com>
> Cc: Wolfgang Denk <wd@denx.de>
> Cc: Stefano Babic <sbabic@denx.de>
> ---
> .../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;
>
Applied to u-boot-imx, thanks.
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
=====================================================================
^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-08-10 18:51 ` [U-Boot] [PATCH] mxc_spi: Round up clock divider Benoît Thébaudeau
2012-08-11 10:37 ` Stefano Babic
2012-08-11 14:23 ` Benoît Thébaudeau
2012-08-20 7:54 ` Stefano Babic
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