[RFC PATCH] pinctrl-single: Use of pinctrl-single for external device over I2C
Vaibhav Hiremath
vaibhav.hiremath at linaro.org
Thu Jul 2 09:53:12 PDT 2015
Disclaimer: This is just proof of concept, to trigger discussion on this.
As pinctrl-single driver is used by many platforms, we should be very careful
here.
I have kept couple of print statement delibrately to match regmap.
Summary:
In some usecases, the external device (in my case it PMIC over I2C)
does support pin in multiple configuration, we may need to control/configure them
during boot or runtime.
In my usecase of PMIC 88PM860, as per spec, 88PM860.GPIO_0 can be configured to
000 = GPIO input mode
001 = GPIO output mode
010 = SLEEPOUTN mirror mode
011 = Buck4 FPWM enable
100 = 32 Khz output buffer mode
101 = PMICINTN output mode
110 = HW_RESET1 mode
111 = HW_RESET2 mode
You can get more details on History or past discussion on this subject -
https://lkml.org/lkml/2015/6/23/170
So we discussed about using pinctrl-single driver for this, but as we know,
pinctrl-single driver has some restrictions,
- use raw read/write
- use of raw spin lock api's
I started with writing fresh driver for pinctrl-i2c, but during that I felt
I am just duplicating all the code, so decided to see whether we can reuse
pinctrl-single driver.
So this patch is proof of concept for using pinctrl-single driver for external
devices, over I2C, SPI, etc...
The idea here is,
Represent external device as another 'pinctrl' device, and get hold of it's regmap
using dev_get_regmap() on parent. This works :)
Still I haven't figured out how to handle raw_spic_lock api's as I2C bus
may sleep and you can not disable preemption. So currently it does print anoying BUG
inside pcs_set_mux().
Testing:
- I have tested this on BeagleBone Bloack
- PXA1928 based platform for MMIO (PXA native muxing)
- PMIC 88PM800 muxing (GPIO 0)
Comments are welcome...good, bad, accepted, nacked, acked, suggestions...
Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath at linaro.org>
---
arch/arm64/boot/dts/marvell/pxa1928-helium.dts | 15 +++
drivers/mfd/88pm800.c | 41 +++++++
drivers/pinctrl/pinctrl-single.c | 159 +++++++++++++------------
3 files changed, 140 insertions(+), 75 deletions(-)
diff --git a/arch/arm64/boot/dts/marvell/pxa1928-helium.dts b/arch/arm64/boot/dts/marvell/pxa1928-helium.dts
index 91b7a1a..25967a6 100644
--- a/arch/arm64/boot/dts/marvell/pxa1928-helium.dts
+++ b/arch/arm64/boot/dts/marvell/pxa1928-helium.dts
@@ -138,6 +138,8 @@
status = "okay";
pmic1: 88pm860 at 30 {
compatible = "marvell,88pm800";
+ pinctrl-names = "default";
+ pinctrl-0 = <&gpio0_32khz_pins>;
reg = <0x30>;
interrupts = <0 77 0x4>;
interrupt-parent = <&gic>;
@@ -319,6 +321,19 @@
regulator-max-microvolt = <2800000>;
};
};
+ pinctrl-i2c {
+ compatible = "pinctrl-i2c";
+ status = "okay";
+
+ pinctrl-single,size = <0xff>;
+ pinctrl-single,function-mask = <0xff>;
+ pinctrl-single,register-width = <8>;
+
+ gpio0_32khz_pins: pinmux_gpio0_32khz_pins {
+ pinctrl-single,pins = <0x30 0x8>;
+ };
+
+ };
rtc {
compatible = "marvell,88pm80x-rtc";
status = "okay";
diff --git a/drivers/mfd/88pm800.c b/drivers/mfd/88pm800.c
index ae2fbbd..3ca381e 100644
--- a/drivers/mfd/88pm800.c
+++ b/drivers/mfd/88pm800.c
@@ -128,6 +128,14 @@ static const struct of_device_id pm80x_of_match_table[] = {
{},
};
+static struct mfd_cell pinctrl_devs[] = {
+ {
+ .name = "pinctrl-i2c",
+ .of_compatible = "pinctrl-i2c",
+ .id = -1,
+ },
+};
+
static struct resource rtc_resources[] = {
{
.name = "88pm80x-rtc",
@@ -338,6 +346,21 @@ static int device_onkey_init(struct pm80x_chip *chip,
return 0;
}
+static int device_pinctrl_init(struct pm80x_chip *chip,
+ struct pm80x_platform_data *pdata)
+{
+ int ret;
+
+ ret = mfd_add_devices(chip->dev, 0, &pinctrl_devs[0],
+ ARRAY_SIZE(pinctrl_devs), NULL, 0, NULL);
+ if (ret) {
+ dev_err(chip->dev, "Failed to add pinctrl subdev\n");
+ return ret;
+ }
+
+ return 0;
+}
+
static int device_rtc_init(struct pm80x_chip *chip,
struct pm80x_platform_data *pdata)
{
@@ -602,6 +625,12 @@ static int device_800_init(struct pm80x_chip *chip,
goto out_dev;
}
+ ret = device_pinctrl_init(chip, pdata);
+ if (ret) {
+ dev_err(chip->dev, "Failed to add pinctrl subdev\n");
+ goto out;
+ }
+
ret = device_rtc_init(chip, pdata);
if (ret) {
dev_err(chip->dev, "Failed to add rtc subdev\n");
@@ -751,6 +780,8 @@ static int pm800_probe(struct i2c_client *client,
struct pm80x_platform_data *pdata = dev_get_platdata(&client->dev);
struct device_node *np = client->dev.of_node;
struct pm80x_subchip *subchip;
+ struct pinctrl *p;
+ struct pinctrl_state *state_default;
if (!pdata && !np) {
dev_err(&client->dev,
@@ -775,6 +806,7 @@ static int pm800_probe(struct i2c_client *client,
chip = i2c_get_clientdata(client);
+ printk("%s:%d chip->regmap - %x\n", __func__, __LINE__, chip->regmap);
/* init subchip for PM800 */
subchip =
devm_kzalloc(&client->dev, sizeof(struct pm80x_subchip),
@@ -811,6 +843,15 @@ static int pm800_probe(struct i2c_client *client,
goto err_device_init;
}
+ p = devm_pinctrl_get(&client->dev);
+ if (p) {
+ state_default = pinctrl_lookup_state(p, PINCTRL_STATE_DEFAULT);
+ if (IS_ERR(state_default))
+ dev_info(&client->dev, "missing default pinctrl state\n");
+ else
+ pinctrl_select_state(p, state_default);
+ }
+
/* System reboot notifier and shutdown callback */
chip->reboot_notifier.notifier_call = reboot_notifier_fn;
register_reboot_notifier(&(chip->reboot_notifier));
diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
index b2de09d..26042df 100644
--- a/drivers/pinctrl/pinctrl-single.c
+++ b/drivers/pinctrl/pinctrl-single.c
@@ -16,6 +16,7 @@
#include <linux/err.h>
#include <linux/list.h>
#include <linux/interrupt.h>
+#include <linux/regmap.h>
#include <linux/irqchip/chained_irq.h>
@@ -61,7 +62,7 @@ struct pcs_pingroup {
* @val: register value
*/
struct pcs_func_vals {
- void __iomem *reg;
+ unsigned int reg;
unsigned val;
unsigned mask;
};
@@ -236,6 +237,8 @@ struct pcs_device {
unsigned ngroups;
unsigned nfuncs;
struct pinctrl_desc desc;
+ struct regmap *regmap;
+ struct regmap_config regmap_config;
unsigned (*read)(void __iomem *reg);
void (*write)(unsigned val, void __iomem *reg);
};
@@ -263,34 +266,18 @@ static enum pin_config_param pcs_bias[] = {
* does not help in this case.
*/
-static unsigned __maybe_unused pcs_readb(void __iomem *reg)
+static unsigned pcs_read(struct regmap *map, unsigned int reg)
{
- return readb(reg);
-}
+ unsigned int val;
-static unsigned __maybe_unused pcs_readw(void __iomem *reg)
-{
- return readw(reg);
-}
-
-static unsigned __maybe_unused pcs_readl(void __iomem *reg)
-{
- return readl(reg);
-}
-
-static void __maybe_unused pcs_writeb(unsigned val, void __iomem *reg)
-{
- writeb(val, reg);
-}
+ regmap_read(map, reg, &val);
-static void __maybe_unused pcs_writew(unsigned val, void __iomem *reg)
-{
- writew(val, reg);
+ return val;
}
-static void __maybe_unused pcs_writel(unsigned val, void __iomem *reg)
+static void pcs_write(struct regmap *map, unsigned val, unsigned int reg)
{
- writel(val, reg);
+ regmap_write(map, reg, val);
}
static int pcs_get_groups_count(struct pinctrl_dev *pctldev)
@@ -351,7 +338,7 @@ static void pcs_pin_dbg_show(struct pinctrl_dev *pctldev,
pcs = pinctrl_dev_get_drvdata(pctldev);
mux_bytes = pcs->width / BITS_PER_BYTE;
- val = pcs->read(pcs->base + pin * mux_bytes);
+ val = pcs_read(pcs->regmap, pin * mux_bytes);
seq_printf(s, "%08x %s " , val, DRIVER_NAME);
}
@@ -472,7 +459,7 @@ static int pcs_set_mux(struct pinctrl_dev *pctldev, unsigned fselector,
vals = &func->vals[i];
raw_spin_lock_irqsave(&pcs->lock, flags);
- val = pcs->read(vals->reg);
+ val = pcs_read(pcs->regmap, vals->reg);
if (pcs->bits_per_mux)
mask = vals->mask;
@@ -481,7 +468,7 @@ static int pcs_set_mux(struct pinctrl_dev *pctldev, unsigned fselector,
val &= ~mask;
val |= (vals->val & mask);
- pcs->write(val, vals->reg);
+ pcs_write(pcs->regmap, val, vals->reg);
raw_spin_unlock_irqrestore(&pcs->lock, flags);
}
@@ -507,9 +494,9 @@ static int pcs_request_gpio(struct pinctrl_dev *pctldev,
|| pin < frange->offset)
continue;
mux_bytes = pcs->width / BITS_PER_BYTE;
- data = pcs->read(pcs->base + pin * mux_bytes) & ~pcs->fmask;
+ data = pcs_read(pcs->regmap, pin * mux_bytes) & ~pcs->fmask;
data |= frange->gpiofunc;
- pcs->write(data, pcs->base + pin * mux_bytes);
+ pcs_write(pcs->regmap, data, pin * mux_bytes);
break;
}
return 0;
@@ -579,7 +566,7 @@ static int pcs_pinconf_get(struct pinctrl_dev *pctldev,
}
offset = pin * (pcs->width / BITS_PER_BYTE);
- data = pcs->read(pcs->base + offset) & func->conf[i].mask;
+ data = pcs_read(pcs->regmap, offset) & func->conf[i].mask;
switch (func->conf[i].param) {
/* 4 parameters */
case PIN_CONFIG_BIAS_PULL_DOWN:
@@ -637,7 +624,7 @@ static int pcs_pinconf_set(struct pinctrl_dev *pctldev,
continue;
offset = pin * (pcs->width / BITS_PER_BYTE);
- data = pcs->read(pcs->base + offset);
+ data = pcs_read(pcs->regmap, offset);
arg = pinconf_to_config_argument(configs[j]);
switch (func->conf[i].param) {
/* 2 parameters */
@@ -668,7 +655,7 @@ static int pcs_pinconf_set(struct pinctrl_dev *pctldev,
default:
return -ENOTSUPP;
}
- pcs->write(data, pcs->base + offset);
+ pcs_write(pcs->regmap, data, offset);
break;
}
@@ -757,6 +744,7 @@ static int pcs_add_pin(struct pcs_device *pcs, unsigned offset,
struct pcs_soc_data *pcs_soc = &pcs->socdata;
struct pinctrl_pin_desc *pin;
struct pcs_name *pn;
+ resource_size_t start = 0;
int i;
i = pcs->pins.cur;
@@ -766,22 +754,25 @@ static int pcs_add_pin(struct pcs_device *pcs, unsigned offset,
return -ENOMEM;
}
+ if (pcs->res)
+ start = pcs->res->start;
+
if (pcs_soc->irq_enable_mask) {
unsigned val;
- val = pcs->read(pcs->base + offset);
+ val = pcs_read(pcs->regmap, offset);
if (val & pcs_soc->irq_enable_mask) {
dev_dbg(pcs->dev, "irq enabled at boot for pin at %lx (%x), clearing\n",
- (unsigned long)pcs->res->start + offset, val);
+ (unsigned long)start + offset, val);
val &= ~pcs_soc->irq_enable_mask;
- pcs->write(val, pcs->base + offset);
+ pcs_write(pcs->regmap, val, offset);
}
}
pin = &pcs->pins.pa[i];
pn = &pcs->names[i];
sprintf(pn->name, "%lx.%u",
- (unsigned long)pcs->res->start + offset, pin_pos);
+ (unsigned long)start + offset, pin_pos);
pin->name = pn->name;
pin->number = i;
pcs->pins.cur++;
@@ -1168,7 +1159,7 @@ static int pcs_parse_one_pinctrl_entry(struct pcs_device *pcs,
offset = be32_to_cpup(mux + index++);
val = be32_to_cpup(mux + index++);
- vals[found].reg = pcs->base + offset;
+ vals[found].reg = offset;
vals[found].val = val;
pin = pcs_get_pin_by_offset(pcs, offset);
@@ -1296,7 +1287,7 @@ static int pcs_parse_bits_in_pinctrl_entry(struct pcs_device *pcs,
}
vals[found].mask = submask;
- vals[found].reg = pcs->base + offset;
+ vals[found].reg = offset;
vals[found].val = val_pos;
pin = pcs_get_pin_by_offset(pcs, offset);
@@ -1540,7 +1531,7 @@ static int pcs_add_gpio_func(struct device_node *node, struct pcs_device *pcs)
* @node: list node
*/
struct pcs_interrupt {
- void __iomem *reg;
+ unsigned int reg;
irq_hw_number_t hwirq;
unsigned int irq;
struct list_head node;
@@ -1570,12 +1561,12 @@ static inline void pcs_irq_set(struct pcs_soc_data *pcs_soc,
soc_mask = pcs_soc->irq_enable_mask;
raw_spin_lock(&pcs->lock);
- mask = pcs->read(pcswi->reg);
+ mask = pcs_read(pcs->regmap, pcswi->reg);
if (enable)
mask |= soc_mask;
else
mask &= ~soc_mask;
- pcs->write(mask, pcswi->reg);
+ pcs_write(pcs->regmap, mask, pcswi->reg);
raw_spin_unlock(&pcs->lock);
}
@@ -1644,7 +1635,7 @@ static int pcs_irq_handle(struct pcs_soc_data *pcs_soc)
pcswi = list_entry(pos, struct pcs_interrupt, node);
raw_spin_lock(&pcs->lock);
- mask = pcs->read(pcswi->reg);
+ mask = pcs_read(pcs->regmap, pcswi->reg);
raw_spin_unlock(&pcs->lock);
if (mask & pcs_soc->irq_status_mask) {
generic_handle_irq(irq_find_mapping(pcs->domain,
@@ -1705,7 +1696,7 @@ static int pcs_irqdomain_map(struct irq_domain *d, unsigned int irq,
if (!pcswi)
return -ENOMEM;
- pcswi->reg = pcs->base + hwirq;
+ pcswi->reg = hwirq;
pcswi->hwirq = hwirq;
pcswi->irq = irq;
@@ -1835,6 +1826,7 @@ static int pcs_probe(struct platform_device *pdev)
dev_err(&pdev->dev, "could not allocate\n");
return -ENOMEM;
}
+
pcs->dev = &pdev->dev;
raw_spin_lock_init(&pcs->lock);
mutex_init(&pcs->mutex);
@@ -1868,47 +1860,63 @@ static int pcs_probe(struct platform_device *pdev)
pcs->bits_per_mux = of_property_read_bool(np,
"pinctrl-single,bit-per-mux");
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!res) {
- dev_err(pcs->dev, "could not get resource\n");
- return -ENODEV;
- }
+ if (of_device_is_compatible(np, "pinctrl-i2c")) {
+ pcs->regmap = dev_get_regmap(pdev->dev.parent, NULL);
- pcs->res = devm_request_mem_region(pcs->dev, res->start,
- resource_size(res), DRIVER_NAME);
- if (!pcs->res) {
- dev_err(pcs->dev, "could not get mem_region\n");
- return -EBUSY;
- }
+ PCS_GET_PROP_U32("pinctrl-single,size", &pcs->size,
+ "size not specified\n");
+;
+ } else {
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(pcs->dev, "could not get resource\n");
+ return -ENODEV;
+ }
+
+ pcs->res = devm_request_mem_region(pcs->dev, res->start,
+ resource_size(res), DRIVER_NAME);
+ if (!pcs->res) {
+ dev_err(pcs->dev, "could not get mem_region\n");
+ return -EBUSY;
+ }
+
+ pcs->size = resource_size(pcs->res);
+ pcs->base = devm_ioremap(pcs->dev, pcs->res->start, pcs->size);
+ if (!pcs->base) {
+ dev_err(pcs->dev, "could not ioremap\n");
+ return -ENODEV;
+ }
+
+ switch (pcs->width) {
+ case 8:
+ pcs->regmap_config.reg_bits = 8;
+ pcs->regmap_config.val_bits = 8;
+ pcs->regmap_config.reg_stride = 1;
+ break;
+ case 16:
+ pcs->regmap_config.reg_bits = 16;
+ pcs->regmap_config.val_bits = 16;
+ pcs->regmap_config.reg_stride = 2;
+ break;
+ case 32:
+ pcs->regmap_config.reg_bits = 32;
+ pcs->regmap_config.val_bits = 32;
+ pcs->regmap_config.reg_stride = 4;
+ break;
+ default:
+ break;
+ }
+
+ pcs->regmap = regmap_init_mmio(&pdev->dev, pcs->base, &pcs->regmap_config);
- pcs->size = resource_size(pcs->res);
- pcs->base = devm_ioremap(pcs->dev, pcs->res->start, pcs->size);
- if (!pcs->base) {
- dev_err(pcs->dev, "could not ioremap\n");
- return -ENODEV;
}
+ printk("%s:%d: regmap - %x size - %d\n", __func__ , __LINE__, pcs->regmap, pcs->size);
+
INIT_RADIX_TREE(&pcs->pgtree, GFP_KERNEL);
INIT_RADIX_TREE(&pcs->ftree, GFP_KERNEL);
platform_set_drvdata(pdev, pcs);
- switch (pcs->width) {
- case 8:
- pcs->read = pcs_readb;
- pcs->write = pcs_writeb;
- break;
- case 16:
- pcs->read = pcs_readw;
- pcs->write = pcs_writew;
- break;
- case 32:
- pcs->read = pcs_readl;
- pcs->write = pcs_writel;
- break;
- default:
- break;
- }
-
pcs->desc.name = DRIVER_NAME;
pcs->desc.pctlops = &pcs_pinctrl_ops;
pcs->desc.pmxops = &pcs_pinmux_ops;
@@ -2008,6 +2016,7 @@ static const struct of_device_id pcs_of_match[] = {
{ .compatible = "ti,am437-padconf", .data = &pinctrl_single_am437x },
{ .compatible = "pinctrl-single", .data = &pinctrl_single },
{ .compatible = "pinconf-single", .data = &pinconf_single },
+ { .compatible = "pinctrl-i2c", .data = &pinctrl_single },
{ },
};
MODULE_DEVICE_TABLE(of, pcs_of_match);
--
1.9.1
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