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pinctrl: imx: work around select input quirk

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The select input for some pin may not be implemented using the regular
select input register but the general purpose register.  A real example
is that imx6q designers found the select input for USB OTG ID pin is
missing at the very late stage, and can not add a new select input
register but have to use a general purpose register bit to implement it.

The patch adds a workaround for such select input quirk by interpreting
the input_val cell of pin function ID in a different way, so that all
the info that needed for setting up select input bits in general purpose
register could be decoded from there.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Shawn Guo 2013-08-04 21:39:23 +08:00 committed by Linus Walleij
parent 3efa921d5b
commit 94176faf27
1 changed files with 32 additions and 2 deletions
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34
drivers/pinctrl/pinctrl-imx.c
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@ -239,8 +239,38 @@ static int imx_pmx_enable(struct pinctrl_dev *pctldev, unsigned selector,
dev_dbg(ipctl->dev, "write: offset 0x%x val 0x%x\n",
pin_reg->mux_reg, mux[i]);
/* some pins also need select input setting, set it if found */
if (input_reg[i]) {
/*
* If the select input value begins with 0xff, it's a quirky
* select input and the value should be interpreted as below.
* 31 23 15 7 0
* | 0xff | shift | width | select |
* It's used to work around the problem that the select
* input for some pin is not implemented in the select
* input register but in some general purpose register.
* We encode the select input value, width and shift of
* the bit field into input_val cell of pin function ID
* in device tree, and then decode them here for setting
* up the select input bits in general purpose register.
*/
if (input_val[i] >> 24 == 0xff) {
u32 val = input_val[i];
u8 select = val & 0xff;
u8 width = (val >> 8) & 0xff;
u8 shift = (val >> 16) & 0xff;
u32 mask = ((1 << width) - 1) << shift;
/*
* The input_reg[i] here is actually some IOMUXC general
* purpose register, not regular select input register.
*/
val = readl(ipctl->base + input_reg[i]);
val &= ~mask;
val |= select << shift;
writel(val, ipctl->base + input_reg[i]);
} else if (input_reg[i]) {
/*
* Regular select input register can never be at offset
* 0, and we only print register value for regular case.
*/
writel(input_val[i], ipctl->base + input_reg[i]);
dev_dbg(ipctl->dev,
"==>select_input: offset 0x%x val 0x%x\n",