u-boot-brain/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c
Masahiro Yamada fdd15b6a86 pinctrl: uniphier: set input-enable before pin-muxing
While IECTRL is disabled, input signals are pulled-down internally.
If pin-muxing is set up first, glitch signals (Low to High transition)
might be input to hardware blocks.

Bad case scenario:
[1] The hardware block is already running before pinctrl is handled.
   (the reset is de-asserted by default or by a firmware, for example)
[2] The pin-muxing is set up.  The input signals to hardware block
   are pulled-down by the chip-internal biasing.
[3] The pins are input-enabled.  The signals from the board reach the
    hardware block.

Actually, one invalid character is input to the UART blocks for such
SoCs as PH1-LD4, PH1-sLD8, where UART devices start to run at the
power on reset.

To avoid such problems, pins should be input-enabled before muxing.

[ ported from Linux commit bac7f4c1bf5e7c6ccd5bb71edc015b26c77f7460 ]

Fixes: 5dc626f836 ("pinctrl: uniphier: add UniPhier pinctrl core support")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2016-03-09 01:10:52 +09:00

155 lines
3.8 KiB
C

/*
* Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <mapmem.h>
#include <linux/io.h>
#include <linux/err.h>
#include <dm/device.h>
#include <dm/pinctrl.h>
#include "pinctrl-uniphier.h"
DECLARE_GLOBAL_DATA_PTR;
static int uniphier_pinctrl_get_groups_count(struct udevice *dev)
{
struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
return priv->socdata->groups_count;
}
static const char *uniphier_pinctrl_get_group_name(struct udevice *dev,
unsigned selector)
{
struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
return priv->socdata->groups[selector].name;
}
static int uniphier_pinmux_get_functions_count(struct udevice *dev)
{
struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
return priv->socdata->functions_count;
}
static const char *uniphier_pinmux_get_function_name(struct udevice *dev,
unsigned selector)
{
struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
return priv->socdata->functions[selector];
}
static void uniphier_pinconf_input_enable(struct udevice *dev, unsigned pin)
{
struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
int pins_count = priv->socdata->pins_count;
const struct uniphier_pinctrl_pin *pins = priv->socdata->pins;
int i;
for (i = 0; i < pins_count; i++) {
if (pins[i].number == pin) {
unsigned int iectrl;
u32 tmp;
iectrl = uniphier_pin_get_iectrl(pins[i].data);
tmp = readl(priv->base + UNIPHIER_PINCTRL_IECTRL);
tmp |= 1 << iectrl;
writel(tmp, priv->base + UNIPHIER_PINCTRL_IECTRL);
}
}
}
static void uniphier_pinmux_set_one(struct udevice *dev, unsigned pin,
unsigned muxval)
{
struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
unsigned mux_bits = priv->socdata->mux_bits;
unsigned reg_stride = priv->socdata->reg_stride;
unsigned reg, reg_end, shift, mask;
u32 tmp;
/* some pins need input-enabling */
uniphier_pinconf_input_enable(dev, pin);
reg = UNIPHIER_PINCTRL_PINMUX_BASE + pin * mux_bits / 32 * reg_stride;
reg_end = reg + reg_stride;
shift = pin * mux_bits % 32;
mask = (1U << mux_bits) - 1;
/*
* If reg_stride is greater than 4, the MSB of each pinsel shall be
* stored in the offset+4.
*/
for (; reg < reg_end; reg += 4) {
tmp = readl(priv->base + reg);
tmp &= ~(mask << shift);
tmp |= (mask & muxval) << shift;
writel(tmp, priv->base + reg);
muxval >>= mux_bits;
}
if (priv->socdata->load_pinctrl)
writel(1, priv->base + UNIPHIER_PINCTRL_LOAD_PINMUX);
}
static int uniphier_pinmux_group_set(struct udevice *dev,
unsigned group_selector,
unsigned func_selector)
{
struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
const struct uniphier_pinctrl_group *grp =
&priv->socdata->groups[group_selector];
int i;
for (i = 0; i < grp->num_pins; i++)
uniphier_pinmux_set_one(dev, grp->pins[i], grp->muxvals[i]);
return 0;
}
const struct pinctrl_ops uniphier_pinctrl_ops = {
.get_groups_count = uniphier_pinctrl_get_groups_count,
.get_group_name = uniphier_pinctrl_get_group_name,
.get_functions_count = uniphier_pinmux_get_functions_count,
.get_function_name = uniphier_pinmux_get_function_name,
.pinmux_group_set = uniphier_pinmux_group_set,
.set_state = pinctrl_generic_set_state,
};
int uniphier_pinctrl_probe(struct udevice *dev,
struct uniphier_pinctrl_socdata *socdata)
{
struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
fdt_addr_t addr;
fdt_size_t size;
addr = fdtdec_get_addr_size(gd->fdt_blob, dev->of_offset, "reg",
&size);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
priv->base = map_sysmem(addr, size);
if (!priv->base)
return -ENOMEM;
priv->socdata = socdata;
return 0;
}
int uniphier_pinctrl_remove(struct udevice *dev)
{
struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
unmap_sysmem(priv->base);
return 0;
}