From 94176faf279ba96394f77cde62b1fdb8304ed30d Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Sun, 4 Aug 2013 21:39:23 +0800 Subject: [PATCH] pinctrl: imx: work around select input quirk 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 Tested-by: Peter Chen Signed-off-by: Linus Walleij --- drivers/pinctrl/pinctrl-imx.c | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/drivers/pinctrl/pinctrl-imx.c b/drivers/pinctrl/pinctrl-imx.c index dea739a1c81f..df80ab6d16b9 100644 --- a/drivers/pinctrl/pinctrl-imx.c +++ b/drivers/pinctrl/pinctrl-imx.c @@ -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",