[PATCH] pinctrl: aspeed-g5: Delay acquisition of regmaps

From: Andrew Jeffery
Date: Wed Jul 24 2019 - 04:02:19 EST

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While sorting out some devicetree issues I found that the pinctrl driver
was failing to acquire its GFX regmap even though the phandle was
present in the devicetree:

[ 0.124190] aspeed-g5-pinctrl 1e6e2000.syscon:pinctrl: No GFX phandle found, some mux configurations may fail

Without access to the GFX regmap we fail to configure the mux for the
VPO function:

[ 1.548866] pinctrl core: add 1 pinctrl maps
[ 1.549826] aspeed-g5-pinctrl 1e6e2000.syscon:pinctrl: found group selector 164 for VPO
[ 1.550638] aspeed-g5-pinctrl 1e6e2000.syscon:pinctrl: request pin 144 (V20) for 1e6e6000.display
[ 1.551346] aspeed-g5-pinctrl 1e6e2000.syscon:pinctrl: request pin 145 (U19) for 1e6e6000.display
...
[ 1.562057] aspeed-g5-pinctrl 1e6e2000.syscon:pinctrl: request pin 218 (T22) for 1e6e6000.display
[ 1.562541] aspeed-g5-pinctrl 1e6e2000.syscon:pinctrl: request pin 219 (R20) for 1e6e6000.display
[ 1.563113] Muxing pin 144 for VPO
[ 1.563456] Want SCU8C[0x00000001]=0x1, got 0x0 from 0x00000000
[ 1.564624] aspeed_gfx 1e6e6000.display: Error applying setting, reverse things back

This turned out to be a simple problem of timing: The ASPEED pinctrl
driver is probed during arch_initcall(), while GFX is processed much
later. As such the GFX syscon is not yet registered during the pinctrl
probe() and we get an -EPROBE_DEFER when we try to look it up, however
we must not defer probing the pinctrl driver for the inability to mux
some GFX-related functions.

Switch to lazily grabbing the regmaps when they're first required by the
mux configuration. This generates a bit of noise in the patch as we have
to drop the `const` qualifier on arguments for several function
prototypes, but has the benefit of working.

I've smoke tested this for the ast2500-evb under qemu with a dummy
graphics device. We now succeed in our attempts to configure the SoC's
VPO pinmux function.

Fixes: 7d29ed88acbb ("pinctrl: aspeed: Read and write bits in LPC and GFX controllers")
Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx>
---
drivers/pinctrl/aspeed/pinctrl-aspeed-g4.c | 2 +-
drivers/pinctrl/aspeed/pinctrl-aspeed-g5.c | 92 +++++++++++++++-------
drivers/pinctrl/aspeed/pinctrl-aspeed.c | 12 ++-
drivers/pinctrl/aspeed/pinmux-aspeed.h | 5 +-
4 files changed, 74 insertions(+), 37 deletions(-)

diff --git a/drivers/pinctrl/aspeed/pinctrl-aspeed-g4.c b/drivers/pinctrl/aspeed/pinctrl-aspeed-g4.c
index 384396cbb22d..22256576b69a 100644
--- a/drivers/pinctrl/aspeed/pinctrl-aspeed-g4.c
+++ b/drivers/pinctrl/aspeed/pinctrl-aspeed-g4.c
@@ -2412,7 +2412,7 @@ static const struct aspeed_pin_config aspeed_g4_configs[] = {
{ PIN_CONFIG_INPUT_DEBOUNCE, { C14, B14 }, SCUA8, 27 },
};

-static int aspeed_g4_sig_expr_set(const struct aspeed_pinmux_data *ctx,
+static int aspeed_g4_sig_expr_set(struct aspeed_pinmux_data *ctx,
const struct aspeed_sig_expr *expr,
bool enable)
{
diff --git a/drivers/pinctrl/aspeed/pinctrl-aspeed-g5.c b/drivers/pinctrl/aspeed/pinctrl-aspeed-g5.c
index 053101f795a2..ba6438ac4d72 100644
--- a/drivers/pinctrl/aspeed/pinctrl-aspeed-g5.c
+++ b/drivers/pinctrl/aspeed/pinctrl-aspeed-g5.c
@@ -2507,6 +2507,61 @@ static struct aspeed_pin_config aspeed_g5_configs[] = {
{ PIN_CONFIG_INPUT_DEBOUNCE, { A20, B19 }, SCUA8, 27 },
};

+static struct regmap *aspeed_g5_acquire_regmap(struct aspeed_pinmux_data *ctx,
+ int ip)
+{
+ if (ip == ASPEED_IP_SCU) {
+ WARN(!ctx->maps[ip], "Missing SCU syscon!");
+ return ctx->maps[ip];
+ }
+
+ if (ip >= ASPEED_NR_PINMUX_IPS)
+ return ERR_PTR(-EINVAL);
+
+ if (likely(ctx->maps[ip]))
+ return ctx->maps[ip];
+
+ if (ip == ASPEED_IP_GFX) {
+ struct device_node *node;
+ struct regmap *map;
+
+ node = of_parse_phandle(ctx->dev->of_node,
+ "aspeed,external-nodes", 0);
+ if (node) {
+ map = syscon_node_to_regmap(node);
+ of_node_put(node);
+ if (IS_ERR(map))
+ return map;
+ } else
+ return ERR_PTR(-ENODEV);
+
+ ctx->maps[ASPEED_IP_GFX] = map;
+ dev_dbg(ctx->dev, "Acquired GFX regmap");
+ return map;
+ }
+
+ if (ip == ASPEED_IP_LPC) {
+ struct device_node *node;
+ struct regmap *map;
+
+ node = of_parse_phandle(ctx->dev->of_node,
+ "aspeed,external-nodes", 1);
+ if (node) {
+ map = syscon_node_to_regmap(node->parent);
+ of_node_put(node);
+ if (IS_ERR(map))
+ return map;
+ } else
+ map = ERR_PTR(-ENODEV);
+
+ ctx->maps[ASPEED_IP_LPC] = map;
+ dev_dbg(ctx->dev, "Acquired LPC regmap");
+ return map;
+ }
+
+ return ERR_PTR(-EINVAL);
+}
+
/**
* Configure a pin's signal by applying an expression's descriptor state for
* all descriptors in the expression.
@@ -2520,7 +2575,7 @@ static struct aspeed_pin_config aspeed_g5_configs[] = {
* Return: 0 if the expression is configured as requested and a negative error
* code otherwise
*/
-static int aspeed_g5_sig_expr_set(const struct aspeed_pinmux_data *ctx,
+static int aspeed_g5_sig_expr_set(struct aspeed_pinmux_data *ctx,
const struct aspeed_sig_expr *expr,
bool enable)
{
@@ -2531,9 +2586,15 @@ static int aspeed_g5_sig_expr_set(const struct aspeed_pinmux_data *ctx,
const struct aspeed_sig_desc *desc = &expr->descs[i];
u32 pattern = enable ? desc->enable : desc->disable;
u32 val = (pattern << __ffs(desc->mask));
+ struct regmap *map;

- if (!ctx->maps[desc->ip])
- return -ENODEV;
+ map = aspeed_g5_acquire_regmap(ctx, desc->ip);
+ if (IS_ERR(map)) {
+ dev_err(ctx->dev,
+ "Failed to acquire regmap for IP block %d\n",
+ desc->ip);
+ return PTR_ERR(map);
+ }

/*
* Strap registers are configured in hardware or by early-boot
@@ -2641,34 +2702,11 @@ static struct pinctrl_desc aspeed_g5_pinctrl_desc = {
static int aspeed_g5_pinctrl_probe(struct platform_device *pdev)
{
int i;
- struct regmap *map;
- struct device_node *node;

for (i = 0; i < ARRAY_SIZE(aspeed_g5_pins); i++)
aspeed_g5_pins[i].number = i;

- node = of_parse_phandle(pdev->dev.of_node, "aspeed,external-nodes", 0);
- map = syscon_node_to_regmap(node);
- of_node_put(node);
- if (IS_ERR(map)) {
- dev_warn(&pdev->dev, "No GFX phandle found, some mux configurations may fail\n");
- map = NULL;
- }
- aspeed_g5_pinctrl_data.pinmux.maps[ASPEED_IP_GFX] = map;
-
- node = of_parse_phandle(pdev->dev.of_node, "aspeed,external-nodes", 1);
- if (node) {
- map = syscon_node_to_regmap(node->parent);
- if (IS_ERR(map)) {
- dev_warn(&pdev->dev, "LHC parent is not a syscon, some mux configurations may fail\n");
- map = NULL;
- }
- } else {
- dev_warn(&pdev->dev, "No LHC phandle found, some mux configurations may fail\n");
- map = NULL;
- }
- of_node_put(node);
- aspeed_g5_pinctrl_data.pinmux.maps[ASPEED_IP_LPC] = map;
+ aspeed_g5_pinctrl_data.pinmux.dev = &pdev->dev;

return aspeed_pinctrl_probe(pdev, &aspeed_g5_pinctrl_desc,
&aspeed_g5_pinctrl_data);
diff --git a/drivers/pinctrl/aspeed/pinctrl-aspeed.c b/drivers/pinctrl/aspeed/pinctrl-aspeed.c
index 535db3de490b..54933665b5f8 100644
--- a/drivers/pinctrl/aspeed/pinctrl-aspeed.c
+++ b/drivers/pinctrl/aspeed/pinctrl-aspeed.c
@@ -71,7 +71,7 @@ int aspeed_pinmux_get_fn_groups(struct pinctrl_dev *pctldev,
return 0;
}

-static int aspeed_sig_expr_enable(const struct aspeed_pinmux_data *ctx,
+static int aspeed_sig_expr_enable(struct aspeed_pinmux_data *ctx,
const struct aspeed_sig_expr *expr)
{
int ret;
@@ -86,7 +86,7 @@ static int aspeed_sig_expr_enable(const struct aspeed_pinmux_data *ctx,
return 0;
}

-static int aspeed_sig_expr_disable(const struct aspeed_pinmux_data *ctx,
+static int aspeed_sig_expr_disable(struct aspeed_pinmux_data *ctx,
const struct aspeed_sig_expr *expr)
{
int ret;
@@ -109,7 +109,7 @@ static int aspeed_sig_expr_disable(const struct aspeed_pinmux_data *ctx,
*
* Return: 0 if all expressions are disabled, otherwise a negative error code
*/
-static int aspeed_disable_sig(const struct aspeed_pinmux_data *ctx,
+static int aspeed_disable_sig(struct aspeed_pinmux_data *ctx,
const struct aspeed_sig_expr **exprs)
{
int ret = 0;
@@ -217,8 +217,7 @@ int aspeed_pinmux_set_mux(struct pinctrl_dev *pctldev, unsigned int function,
{
int i;
int ret;
- const struct aspeed_pinctrl_data *pdata =
- pinctrl_dev_get_drvdata(pctldev);
+ struct aspeed_pinctrl_data *pdata = pinctrl_dev_get_drvdata(pctldev);
const struct aspeed_pin_group *pgroup = &pdata->pinmux.groups[group];
const struct aspeed_pin_function *pfunc =
&pdata->pinmux.functions[function];
@@ -306,8 +305,7 @@ int aspeed_gpio_request_enable(struct pinctrl_dev *pctldev,
unsigned int offset)
{
int ret;
- const struct aspeed_pinctrl_data *pdata =
- pinctrl_dev_get_drvdata(pctldev);
+ struct aspeed_pinctrl_data *pdata = pinctrl_dev_get_drvdata(pctldev);
const struct aspeed_pin_desc *pdesc = pdata->pins[offset].drv_data;
const struct aspeed_sig_expr ***prios, **funcs, *expr;

diff --git a/drivers/pinctrl/aspeed/pinmux-aspeed.h b/drivers/pinctrl/aspeed/pinmux-aspeed.h
index 329d54d48667..52d299b59ce2 100644
--- a/drivers/pinctrl/aspeed/pinmux-aspeed.h
+++ b/drivers/pinctrl/aspeed/pinmux-aspeed.h
@@ -702,11 +702,12 @@ struct aspeed_pin_function {
struct aspeed_pinmux_data;

struct aspeed_pinmux_ops {
- int (*set)(const struct aspeed_pinmux_data *ctx,
+ int (*set)(struct aspeed_pinmux_data *ctx,
const struct aspeed_sig_expr *expr, bool enabled);
};

struct aspeed_pinmux_data {
+ struct device *dev;
struct regmap *maps[ASPEED_NR_PINMUX_IPS];

const struct aspeed_pinmux_ops *ops;
@@ -725,7 +726,7 @@ int aspeed_sig_expr_eval(const struct aspeed_pinmux_data *ctx,
const struct aspeed_sig_expr *expr,
bool enabled);

-static inline int aspeed_sig_expr_set(const struct aspeed_pinmux_data *ctx,
+static inline int aspeed_sig_expr_set(struct aspeed_pinmux_data *ctx,
const struct aspeed_sig_expr *expr,
bool enabled)
{
--
2.20.1

Next message: Michael S. Tsirkin: "Re: WARNING in __mmdrop"
Previous message: Dmitry Vyukov: "Re: Reminder: 3 open syzbot bugs in "net/ax25" subsystem"
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