[PATCH 3/3] [U300] Set f_max to 24 MHz for MMC

[PATCH 3/3] [U300] Set f_max to 24 MHz for MMC

[Linus Walleij]

This employs the frequency setting mechanism introduced to the
MMCI to specify that this system can actually be clocked at 24 MHz.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
---
 arch/arm/mach-u300/mmc.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-u300/mmc.c b/arch/arm/mach-u300/mmc.c
index 8bf466b..5681563 100644
--- a/arch/arm/mach-u300/mmc.c
+++ b/arch/arm/mach-u300/mmc.c
@@ -104,6 +104,7 @@ int __devinit mmc_init(struct amba_device *adev)
 	 * we have a regulator we can control instead.
 	 */
 	/* Nominally 2.85V on our platform */
+	mmci_card->mmc0_plat_data.f_max = 24*1024*1024;
 	mmci_card->mmc0_plat_data.status = mmc_status;
 	mmci_card->mmc0_plat_data.gpio_wp = -1;
 	mmci_card->mmc0_plat_data.gpio_cd = -1;
-- 
1.6.3.3

Re: [PATCH 3/3] [U300] Set f_max to 24 MHz for MMC

[David Vrabel]

Linus Walleij wrote:
> 
> +	mmci_card->mmc0_plat_data.f_max = 24*1024*1024;

Is the frequency really 25165824 Hz and not 24000000 Hz?

David
-- 
David Vrabel, Senior Software Engineer, Drivers
CSR, Churchill House, Cambridge Business Park,  Tel: +44 (0)1223 692562
Cowley Road, Cambridge, CB4 0WZ                 http://www.csr.com/


Member of the CSR plc group of companies. CSR plc registered in England and Wales, registered number 4187346, registered office Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, United Kingdom

RE: [PATCH 3/3] [U300] Set f_max to 24 MHz for MMC

[Linus Walleij]

[David Vrabel]

> Linus Walleij wrote:
> > 
> > +	mmci_card->mmc0_plat_data.f_max = 24*1024*1024;
> 
> Is the frequency really 25165824 Hz and not 24000000 Hz?

It's actually 18900000 Hz. This f_max is a physical
limitation and a property of the SoC, so that figure
comes from some semiconductor person.

When combined with the U300 clock framework, the
min() function will resolve to min(18900000, 24000000)
i.e. 18900000 Hz.

Linus Walleij

RE: [PATCH 3/3] [U300] Set f_max to 24 MHz for MMC

[Linus Walleij]

[David Vrabel]

> Linus Walleij wrote:
> > 
> > +	mmci_card->mmc0_plat_data.f_max = 24*1024*1024;
> 
> Is the frequency really 25165824 Hz and not 24000000 Hz?

Or, yes it is 24000000, as was your question, hm,
the 1024 was probably out of habit, I'll change to
24*1000*1000.

Sorry for getting it all backwards, I need vacation.

Linus Walleij