Hi, Marek, On Wed, Aug 10, 2011 at 3:11 PM, Marek Vasut <marek.va...@gmail.com> wrote: > On Wednesday, August 10, 2011 08:26:05 AM Jason Hui wrote: >> On Wed, Aug 10, 2011 at 1:59 PM, Marek Vasut <marek.va...@gmail.com> wrote: >> > On Saturday, July 30, 2011 12:52:53 PM Marek Vasut wrote: >> >> On Saturday, July 30, 2011 08:42:19 AM Jason Hui wrote: >> >> > Hi, Marek, >> >> > >> >> > On Sat, Jul 30, 2011 at 1:09 AM, Marek Vasut <marek.va...@gmail.com> > wrote: >> >> > > On Friday, July 29, 2011 01:24:49 PM Jason Hui wrote: >> >> > >> Hi, Marek, >> >> > >> >> >> > >> On Fri, Jul 29, 2011 at 5:32 PM, Marek Vasut >> >> > >> <marek.va...@gmail.com> >> > >> > wrote: >> >> > >> > Rewrite the mxc_i2c driver. >> >> > >> > >> >> > >> > * This version is much closer to Linux implementation. >> >> > >> > * Fixes IPG_PERCLK being incorrectly used as clock source >> >> > >> > * Fixes behaviour of the driver on iMX51 >> >> > >> > * Clean up coding style a bit ;-) >> >> > >> >> >> > >> I don't think you did the right thing by chaning IPG_PERCLK to >> >> > >> IPG_CLK As I said, the IPG_CLK is for IP register clock, while >> >> > >> IPG_PERCLK is for i2c function clock. >> >> > >> >> >> > >> if you run clock command from mx51evk, you will get: >> >> > >> ... >> >> > >> ipg clock : 66500000Hz >> >> > >> ipg per clock : 665000000Hz >> >> > >> MX51EVK U-Boot > >> >> > >> >> >> > >> It will give you that ipg per clock is 665M, which seems too big. >> >> > >> It is due to we configure >> >> > >> the pre-divider/pos-devider for perclk to zero, which leads to >> >> > >> ipg_per clock to be same as pll2 clock. >> >> > >> But I don't think this will have some issue. >> >> > > >> >> > > Yes it will, the divider will be computed to be maximum in all cases >> >> > > ... you won't be able it divide 665MHz by anything from the table >> >> > > 40-7 in MX51RM to achieve any reasonable frequency. >> >> > > >> >> > > On the contrary, 66.5MHz does give fine results. >> >> > >> >> > it that, we can change the ipg_perclk to low freq, but we should not >> >> > change the i2c clock to ipg_clk, this is not correct. >> >> > >> >> > >> BTW, I have applied your patch and test on mx53evk board, it seems >> >> > >> the i2c does not work correctly. >> >> > > >> >> > > Great. The clock used by the I2C module for this task are likely the >> >> > > module_clock, which are -- like on MX51 -- 66.5MHz. What do you get >> >> > > when you run the "clock" command on MX53EVK ? >> >> > >> >> > I'm not in the office for the whole next week, thus, I can't give you >> >> > the clock output for >> >> > mx53evk, but I'm sure the ipg_perclk on mx53evk is not set at 66.5Mhz. >> >> >> >> Yes, it's 33.3MHz on iMX53. I got a (remote) hand of a MX53 board. The >> >> IPG clock, on the other hand, are 66.5MHz on both MX51 and MX53. Maybe >> >> the issue with PMIC you're seeing is something else? >> >> >> >> btw. how did you obtain these results ? Can you check the FDR divider >> >> value with and without this patch? >> >> You can use the clock command to get it. As for the FDR, you want me to >> check it on i.mx53evk board right? > > Yes please. I hope to get my hands on mx53 system in the evening probably, but > I'd still be grateful if you could test it.
The clock for i2c should be ipg_perclk, the linux kernel code has been fixed by the following commit: commit 9d73242458d9a2fe26e2e240488063d414eacb1c Author: Lothar Waßmann <l...@karo-electronics.de> Date: Mon Jul 4 15:52:17 2011 +0200 mach-mx5: fix the I2C clock parents The clock from which the I2C timing is derived is the ipg_perclk not ipg_clk. I2C bus frequency was lower by a factor of ~8 due to the clock divider calculation being based on 66.5MHz IPG clock while the bus actually uses 8MHz ipg_perclk. Kernel version: 3.0.0-rc2 branch 'imx-for-next' of git://git.pengutronix.de/git/imx/linux-2.6 Signed-off-by: Lothar Waßmann <l...@karo-electronics.de> Signed-off-by: Sascha Hauer <s.ha...@pengutronix.de> Jason > >> >> Jason >> >> >> Thanks >> >> >> >> > Jason >> >> > >> >> > > Thanks >> >> > > >> >> > >> After apply your patch: >> >> > >> MX53EVK U-Boot > pmic dump 30 >> >> > >> PMIC ID: 0x0000ffff [Rev: unknown] >> >> > >> >> >> > >> 0x00: 0001ffff 00ffffff 0039ffff 0000ffff 00ffffff 0000ffff >> >> > >> 0000ffff 0000ffff 0x08: 0000ffff 0000ffff 0000ffff 0000ffff >> >> > >> 0000ffff 0000ffff 0000ffff 0040ffff 0x10: 0000ffff 0000ffff >> >> > >> 0000ffff 0000ffff 0000ffff 0001ffff 0000ffff 0000ffff 0x18: >> >> > >> 0045ffff 0045ffff 0000ffff 0080ffff 0021ffff 0000ffff 0002ffff >> >> > >> 0000ffff 0x20: 0004ffff 0000ffff 0021ffff 0000ffff 0000ffff >> >> > >> 0000ffff 0000ffff 0000ffff 0x28: 0000ffff 0000ffff 0000ffff >> >> > >> 0000ffff 0000ffff 0004ffff 0000ffff 00aeffff >> >> > >> >> >> > >> The old: >> >> > >> MX53EVK U-Boot > pmic dump 30 >> >> > >> PMIC ID: 0x000045d0 [Rev: 2.0] >> >> > >> >> >> > >> 0x00: 00015088 00ffffff 00395208 00000081 00fff7ff 0000401c >> >> > >> 00000418 000045d0 0x08: 00000000 00000000 00000001 00000000 >> >> > >> 00000000 00000040 00000000 00400000 0x10: 00000000 00000000 >> >> > >> 00000000 00000000 00000011 0001ffff 00000000 00007fff 0x18: >> >> > >> 00454a52 00456739 0000631a 0080739c 0021284a 00000a0a 00024fd0 >> >> > >> 000001d8 0x20: 00049208 00000000 00218000 00000000 00000000 >> >> > >> 00000000 00000000 00000000 0x28: 00000000 00000000 00000000 >> >> > >> 00008000 00000000 00046046 000001c0 00aeeaee >> >> > >> >> >> > >> Jason > _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot