On Wed, Jun 12, 2013 at 9:12 PM, Stefano Babic <sba...@denx.de> wrote: > Hi Dirk, > > On 12/06/2013 07:28, Dirk Behme wrote: >> On 11.05.2013 07:25, Dirk Behme wrote: >>> The spi clock divisor is of the form x * (2**y), or x << y, where x is >>> 1 to 16, and y is 0 to 15. Note the similarity with floating point >>> numbers. >>> Convert the desired divisor to the smallest number which is >= desired >>> divisor, >>> and can be represented in this form. The previous algorithm chose a >>> divisor >>> which could be almost twice as large as needed. >>> >>> Signed-off-by: Troy Kisky <troy.ki...@boundarydevices.com> >>> Signed-off-by: Dirk Behme <dirk.be...@gmail.com> >> >> While we are talking about a first -rc now, could we get these two patches >> >> http://patchwork.ozlabs.org/patch/242709/ >> >> http://patchwork.ozlabs.org/patch/243113/ > > Sorry to come late with these two patches - after a first glance when > you post then, I put the patches at the bottom of my queue and I never > checked again. > > I will work them before end of the week. > > Best regards, > Stefano Babic > > >> >> applied? >> >> Thanks >> >> Dirk >> >>> --- >>> >>> Notes: >>> >>> - Changes in v2: Make the alogrithm simpler by removing the -1 as >>> proposed >>> by Troy. Make the pre_div and post_div u32. >>> >>> - This replaces v1 of this patch and depends on the previous sent patch >>> http://patchwork.ozlabs.org/patch/242709/ >>> >>> drivers/spi/mxc_spi.c | 30 ++++++++++++------------------ >>> 1 file changed, 12 insertions(+), 18 deletions(-) >>> >>> diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c >>> index 3e903b3..e87b899 100644 >>> --- a/drivers/spi/mxc_spi.c >>> +++ b/drivers/spi/mxc_spi.c >>> @@ -128,8 +128,8 @@ static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, >>> unsigned int cs, >>> unsigned int max_hz, unsigned int mode) >>> { >>> u32 clk_src = mxc_get_clock(MXC_CSPI_CLK); >>> - s32 pre_div = 1, post_div = 0, i, reg_ctrl, reg_config; >>> - u32 ss_pol = 0, sclkpol = 0, sclkpha = 0; >>> + s32 reg_ctrl, reg_config; >>> + u32 ss_pol = 0, sclkpol = 0, sclkpha = 0, pre_div = 0, post_div = 0; >>> struct cspi_regs *regs = (struct cspi_regs *)mxcs->base; >>> >>> if (max_hz == 0) { >>> @@ -147,26 +147,20 @@ static s32 spi_cfg_mxc(struct mxc_spi_slave >>> *mxcs, unsigned int cs, >>> reg_ctrl |= MXC_CSPICTRL_EN; >>> reg_write(®s->ctrl, reg_ctrl); >>> >>> - /* >>> - * The following computation is taken directly from Freescale's >>> code. >>> - */ >>> if (clk_src > max_hz) { >>> - pre_div = DIV_ROUND_UP(clk_src, max_hz); >>> - if (pre_div > 16) { >>> - post_div = pre_div / 16; >>> - pre_div = 16; >>> - } >>> - if (post_div != 0) { >>> - for (i = 0; i < 16; i++) { >>> - if ((1 << i) >= post_div) >>> - break; >>> - } >>> - if (i == 16) { >>> + pre_div = (clk_src - 1) / max_hz; >>> + /* fls(1) = 1, fls(0x80000000) = 32, fls(16) = 5 */ >>> + post_div = fls(pre_div); >>> + if (post_div > 4) { >>> + post_div -= 4; >>> + if (post_div >= 16) { >>> printf("Error: no divider for the freq: %d\n", >>> max_hz); >>> return -1; >>> } >>> - post_div = i; >>> + pre_div >>= post_div; >>> + } else { >>> + post_div = 0; >>> } >>> } >>> >>> @@ -174,7 +168,7 @@ static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, >>> unsigned int cs, >>> reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_SELCHAN(3)) | >>> MXC_CSPICTRL_SELCHAN(cs); >>> reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_PREDIV(0x0F)) | >>> - MXC_CSPICTRL_PREDIV(pre_div - 1); >>> + MXC_CSPICTRL_PREDIV(pre_div); >>> reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_POSTDIV(0x0F)) | >>> MXC_CSPICTRL_POSTDIV(post_div); >>> >>> >> >> >> > > > -- > ===================================================================== > 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: sba...@denx.de > ===================================================================== > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > http://lists.denx.de/mailman/listinfo/u-boot
Sorry, i didn't understand the conversation here, was this fix applied? Could you please explain. -- Thanks, Jagan. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
