From mboxrd@z Thu Jan  1 00:00:00 1970
From: Magnus Lilja <lilja.magnus@gmail.com>
Date: Fri, 04 Jul 2008 20:28:22 +0200
Subject: [U-Boot-Users] [PATCH 07/10] [ARM] TQMA31: adjust voltage
 regulators in PMIC MC13738
In-Reply-To: <20080704145011.12049.75795.stgit@tq-sewsrv-4.tq-net.de>
References: <20080704144552.12049.55374.stgit@tq-sewsrv-4.tq-net.de>
	<20080704145011.12049.75795.stgit@tq-sewsrv-4.tq-net.de>
Message-ID: <486E6BC6.9020706@gmail.com>
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To: u-boot@lists.denx.de

Hi,

Jens Gehrlein wrote:
> +static int adjust_voltages (void)
> +{
> +	u32 reg;
> +	u32 val;
> +	static struct spi_slave *slave = NULL;
> +
> +	slave = spi_setup_slave(1, 0, 1000000,
> +		SPI_MODE_2 | SPI_CS_HIGH);
> +	if (!slave)
> +		return -1;
> +
> +	if (spi_claim_bus(slave))
> +		return -1;
> +
> +	/* Set PMIC arbitration switchers */
> +	val = 0x000020;
> +	reg = 0x14000000 | val | 0x80000000;

It seems like it's time to create a MC13783 header file containing some helper macros and symbolic names to the 13783's registers so we can write:
reg = MC13783_READ_CMD(MC_REG_FOO);
...
val = something_symbolic | something_symbolic2;
reg = MC13783_WRITE_CMD(MC_REG_FOO, val);
...
etc..


Also, I'm pretty sure some other i.MX31 boards could benefit from changing some voltages in U-boot so perhaps we could have a mc13783-reg.c (-reg as in regulators) file containing stuff like mc13783_set_regulator(MC_VRFDIG, VRFDIG_1V8)?


> +	/*
> +	 * FIXME: switcher settings 0 and 1.
> +	 * Kernel hangs when unpacking itself.
> +	 * Workaround:
> +	 * Up to now CPU can operate at maximum allowed voltage 1.6 V.
> +	 */

I suppose you know that 1.6V is only needed if the CPU is clocked at 532MHz, if it's clocked at 399MHz it can be supplied with 1.2V.


Regards, Magnus