Re: [PATCH v5 2/2] pinctrl: qcom: Add sm8250 lpass lpi pinctrl driver

Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx> · Wed, 2 Dec 2020 09:56:35 +0000

Thanks Bjorn for the review,

On 01/12/2020 19:48, Bjorn Andersson wrote:
On Tue 01 Dec 08:28 CST 2020, Srinivas Kandagatla wrote:

Add initial pinctrl driver to support pin configuration for
LPASS (Low Power Audio SubSystem) LPI (Low Power Island) pinctrl
on SM8250.

This IP is an additional pin control block for Audio Pins on top the
existing SoC Top level pin-controller.
Hardware setup looks like:

TLMM GPIO[146 - 159] --> LPASS LPI GPIO [0 - 13]

This pin controller has some similarities compared to Top level
msm SoC Pin controller like 'each pin belongs to a single group'
and so on. However this one is intended to control only audio
pins in particular, which can not be configured/touched by the
Top level SoC pin controller except setting them as gpios.
Apart from this, slew rate is also available in this block for
certain pins which are connected to SLIMbus or SoundWire Bus.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
---
  drivers/pinctrl/qcom/Kconfig             |   8 +
  drivers/pinctrl/qcom/Makefile            |   1 +
  drivers/pinctrl/qcom/pinctrl-lpass-lpi.c | 727 +++++++++++++++++++++++
  3 files changed, 736 insertions(+)
  create mode 100644 drivers/pinctrl/qcom/pinctrl-lpass-lpi.c

diff --git a/drivers/pinctrl/qcom/Kconfig b/drivers/pinctrl/qcom/Kconfig
index 5fe7b8aaf69d..d3e4e89c2810 100644
--- a/drivers/pinctrl/qcom/Kconfig
+++ b/drivers/pinctrl/qcom/Kconfig
@@ -236,4 +236,12 @@ config PINCTRL_SM8250
  	  Qualcomm Technologies Inc TLMM block found on the Qualcomm
  	  Technologies Inc SM8250 platform.
  
+config PINCTRL_LPASS_LPI
+	tristate "Qualcomm Technologies Inc LPASS LPI pin controller driver"
+	depends on GPIOLIB
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SoCs.
+
  endif
diff --git a/drivers/pinctrl/qcom/Makefile b/drivers/pinctrl/qcom/Makefile
index 9e3d9c91a444..c8520155fb1b 100644
--- a/drivers/pinctrl/qcom/Makefile
+++ b/drivers/pinctrl/qcom/Makefile
@@ -28,3 +28,4 @@ obj-$(CONFIG_PINCTRL_SDM660)   += pinctrl-sdm660.o
  obj-$(CONFIG_PINCTRL_SDM845) += pinctrl-sdm845.o
  obj-$(CONFIG_PINCTRL_SM8150) += pinctrl-sm8150.o
  obj-$(CONFIG_PINCTRL_SM8250) += pinctrl-sm8250.o
+obj-$(CONFIG_PINCTRL_LPASS_LPI) += pinctrl-lpass-lpi.o
diff --git a/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c b/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c
new file mode 100644
index 000000000000..96c63a33fc99
--- /dev/null
+++ b/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c
@@ -0,0 +1,727 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2016-2019, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2020 Linaro Ltd.
+ */
+
+#include <linux/bitops.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/gpio/driver.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include "../core.h"
+#include "../pinctrl-utils.h"
+
+#define LPI_GPIO_CFG_REG		0x00
+#define LPI_GPIO_VALUE_REG		0x04
+#define LPI_SLEW_RATE_CTL_REG		0xa000
+#define LPI_SLEW_RATE_MAX		0x03
+#define LPI_SLEW_BITS_SIZE		0x02
+#define LPI_GPIO_PULL_SHIFT		0x0
+#define LPI_GPIO_PULL_MASK		GENMASK(1, 0)
+#define LPI_GPIO_FUNCTION_SHIFT		0x2
+#define LPI_GPIO_FUNCTION_MASK	GENMASK(5, 2)
+#define LPI_GPIO_OUT_STRENGTH_SHIFT	0x6
+#define LPI_GPIO_OUT_STRENGTH_MASK	GENMASK(8, 6)
+#define LPI_GPIO_OE_SHIFT		0x9
+#define LPI_GPIO_OE_MASK		BIT(9)
+#define LPI_GPIO_DIR_SHIFT		0x1
+#define LPI_GPIO_DIR_MASK		0x2

The naming of these two constants no longer relates the their register.
And you no longer use the MASK, so please drop this.

Yes, most of these defines are redundant can be removed, I will clean 
that up!

That said the use of "shift" still doesn't give away the obvious fact
that this is a single bit specifying if the output should be high or
low. You would capture this by doing something like:

#define LPI_GPIO_VALUE_HIGH	BIT(1)

Sure will make this explicit!

+#define LPI_GPIO_BIAS_DISABLE		0x0
+#define LPI_GPIO_PULL_DOWN		0x1
+#define LPI_GPIO_KEEPER			0x2
+#define LPI_GPIO_PULL_UP		0x3
+#define LPI_GPIO_DS_TO_VAL(v) ((v / 2 - 1) << LPI_GPIO_OUT_STRENGTH_SHIFT)
+#define NO_SLEW				-1
+
+#define LPI_FUNCTION(fname)			                \
+	[LPI_MUX_##fname] = {		                \
+		.name = #fname,				\
+		.groups = fname##_groups,               \
+		.ngroups = ARRAY_SIZE(fname##_groups),	\
+	}
+

+
+static int lpi_gpio_set_mux(struct pinctrl_dev *pctldev, unsigned int function,
+			    unsigned int group_num)
+{
+	struct lpi_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
+	const struct lpi_pingroup *g = &pctrl->data->groups[group_num];
+	u32 val;
+	int i, pin = g->pin;
+
+	for (i = 0; i < g->nfuncs; i++) {
+		if (g->funcs[i] == function)
+			break;
+	}
+
+	if (WARN_ON(i == g->nfuncs))
+		return -EINVAL;
+
+	val = lpi_gpio_read(pctrl, pin, LPI_GPIO_CFG_REG);
+	u32p_replace_bits(&val, i, LPI_GPIO_FUNCTION_MASK);

I really meant FIELD_SET(), but now realize that there's only
FIELD_PREP() and FIELD_GET() in linux/bitfields.h. I think that should
be corrected, but this seems to do the trick...

I knew that FILED_SET does not exists, Howeever using FIELD_* macros 
here to modify bits would still require 2 lines, one to manually clear 
the bits and then use FILED_SET.

replace_bits() api does nicely!

+	lpi_gpio_write(pctrl, pin, LPI_GPIO_CFG_REG, val);
+
+	return 0;
+}
+
+static const struct pinmux_ops lpi_gpio_pinmux_ops = {
+	.get_functions_count	= lpi_gpio_get_functions_count,
+	.get_function_name	= lpi_gpio_get_function_name,
+	.get_function_groups	= lpi_gpio_get_function_groups,
+	.set_mux		= lpi_gpio_set_mux,
+};
+
+static int lpi_config_get(struct pinctrl_dev *pctldev,
+			  unsigned int pin, unsigned long *config)
+{
+	unsigned int param = pinconf_to_config_param(*config);
+	struct lpi_pinctrl *state = dev_get_drvdata(pctldev->dev);
+	unsigned int arg = 0;
+	int is_out;
+	int pull;
+	u32 ctl_reg;
+
+	ctl_reg = lpi_gpio_read(state, pin, LPI_GPIO_CFG_REG);
+	is_out = ctl_reg & LPI_GPIO_OE_MASK;
+	pull = (ctl_reg & LPI_GPIO_PULL_MASK) >> LPI_GPIO_PULL_SHIFT;
+
+	switch (param) {
+	case PIN_CONFIG_BIAS_DISABLE:
+		if (pull == LPI_GPIO_BIAS_DISABLE)
+			arg = 1;
+		break;
+	case PIN_CONFIG_BIAS_PULL_DOWN:
+		if (pull == LPI_GPIO_PULL_DOWN)
+			arg = 1;
+		break;
+	case PIN_CONFIG_BIAS_BUS_HOLD:
+		if (pull == LPI_GPIO_KEEPER)
+			arg = 1;
+		break;
+	case PIN_CONFIG_BIAS_PULL_UP:
+		if (pull == LPI_GPIO_PULL_UP)
+			arg = 1;
+		break;
+	case PIN_CONFIG_INPUT_ENABLE:
+	case PIN_CONFIG_OUTPUT:
+		if (is_out)
+			arg = 1;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	*config = pinconf_to_config_packed(param, arg);
+	return 0;
+}
+
+static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group,
+			  unsigned long *configs, unsigned int nconfs)
+{
+	struct lpi_pinctrl *pctrl = dev_get_drvdata(pctldev->dev);
+	unsigned int param, arg, pullup, strength;
+	bool value, output_enabled = false;
+	const struct lpi_pingroup *g;
+	unsigned long sval;
+	int i, slew_offset;
+	u32 val;
+
+	g = &pctrl->data->groups[group];
+	for (i = 0; i < nconfs; i++) {
+		param = pinconf_to_config_param(configs[i]);
+		arg = pinconf_to_config_argument(configs[i]);
+
+		switch (param) {
+		case PIN_CONFIG_BIAS_DISABLE:
+			pullup = LPI_GPIO_BIAS_DISABLE;
+			break;
+		case PIN_CONFIG_BIAS_PULL_DOWN:
+			pullup = LPI_GPIO_PULL_DOWN;
+			break;
+		case PIN_CONFIG_BIAS_BUS_HOLD:
+			pullup = LPI_GPIO_KEEPER;
+			break;
+		case PIN_CONFIG_BIAS_PULL_UP:
+			pullup = LPI_GPIO_PULL_UP;
+			break;
+		case PIN_CONFIG_INPUT_ENABLE:
+			output_enabled = false;
+			break;
+		case PIN_CONFIG_OUTPUT:
+			output_enabled = true;
+			value = arg;
+			break;
+		case PIN_CONFIG_DRIVE_STRENGTH:
+			strength = arg;
+			break;
+		case PIN_CONFIG_SLEW_RATE:
+			if (arg > LPI_SLEW_RATE_MAX) {
+				dev_err(pctldev->dev, "invalid slew rate %u for pin: %d\n",
+					arg, group);
+				return -EINVAL;
+			}
+
+			slew_offset = g->slew_offset;
+			if (slew_offset == NO_SLEW)
+				break;
+
+			mutex_lock(&pctrl->slew_access_lock);
+			sval = ioread32(pctrl->slew_base + LPI_SLEW_RATE_CTL_REG);
+
+			for (i = 0; i < LPI_SLEW_BITS_SIZE; i++) {
+				assign_bit(slew_offset, &sval, arg & 0x01);
+				slew_offset++;
+				arg = arg >> 1;
+			}

Isn't this loop just the same as

	FIELD_SET(3 << slew_offset, arg & 3, sval)

This will not work FIELD_SET will not clear any bits wich are already 
set! assing_bit will work, but we could do better by adding slew_mask 
per pin rather than slew_offset which should allow us to use 
replace_bits straight away.


And as you already checked arg agains LPI_SLEW_RATE_MAX you should be
able to drop the & 3 there in the middle.

+
+			iowrite32(sval, pctrl->slew_base + LPI_SLEW_RATE_CTL_REG);
+
+			mutex_unlock(&pctrl->slew_access_lock);
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	val = lpi_gpio_read(pctrl, group, LPI_GPIO_CFG_REG);
+
+	u32p_replace_bits(&val, pullup, LPI_GPIO_PULL_MASK);
+	u32p_replace_bits(&val, LPI_GPIO_DS_TO_VAL(strength),
+			  LPI_GPIO_OUT_STRENGTH_MASK);
+	u32p_replace_bits(&val, output_enabled, LPI_GPIO_OE_MASK);
+
+	lpi_gpio_write(pctrl, group, LPI_GPIO_CFG_REG, val);
+
+	if (output_enabled)
+		lpi_gpio_write(pctrl, group, LPI_GPIO_VALUE_REG,
+			       value << LPI_GPIO_DIR_SHIFT);
+
+	return 0;
+}
+
+static const struct pinconf_ops lpi_gpio_pinconf_ops = {
+	.is_generic			= true,
+	.pin_config_group_get		= lpi_config_get,
+	.pin_config_group_set		= lpi_config_set,
+};
+
+static int lpi_gpio_direction_input(struct gpio_chip *chip, unsigned int pin)
+{
+	struct lpi_pinctrl *state = gpiochip_get_data(chip);
+	unsigned long config;
+
+	config = pinconf_to_config_packed(PIN_CONFIG_INPUT_ENABLE, 1);
+
+	return lpi_config_set(state->ctrl, pin, &config, 1);
+}
+
+static int lpi_gpio_direction_output(struct gpio_chip *chip,
+				     unsigned int pin, int val)
+{
+	struct lpi_pinctrl *state = gpiochip_get_data(chip);
+	unsigned long config;
+
+	config = pinconf_to_config_packed(PIN_CONFIG_OUTPUT, val);
+
+	return lpi_config_set(state->ctrl, pin, &config, 1);
+}
+
+static int lpi_gpio_get(struct gpio_chip *chip, unsigned int pin)
+{
+	struct lpi_pinctrl *state = gpiochip_get_data(chip);
+	int value;
+
+	value = lpi_gpio_read(state, pin, LPI_GPIO_CFG_REG);
+	return value;

I must have missed this last round, gpio_get() should return the current
value of the pin, i.e:

Thanks I missed this one as well!
	return lpi_gpio_read(state, pin, LPI_GPIO_VALUE_REG) & BIT(0);

+}
+
+static void lpi_gpio_set(struct gpio_chip *chip, unsigned int pin, int value)
+{
+	struct lpi_pinctrl *state = gpiochip_get_data(chip);
+	unsigned long config;
+
+	config = pinconf_to_config_packed(PIN_CONFIG_OUTPUT, value);
+
+	lpi_config_set(state->ctrl, pin, &config, 1);
+}
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/seq_file.h>
+
+static unsigned int lpi_regval_to_drive(u32 val)
+{
+	return (val + 1) * 2;
+}
+
+static void lpi_gpio_dbg_show_one(struct seq_file *s,
+				  struct pinctrl_dev *pctldev,
+				  struct gpio_chip *chip,
+				  unsigned int offset,
+				  unsigned int gpio)
+{
+	struct lpi_pinctrl *state = gpiochip_get_data(chip);
+	struct pinctrl_pin_desc pindesc;
+	unsigned int func;
+	int is_out;
+	int drive;
+	int pull;
+	u32 ctl_reg;
+
+	static const char * const pulls[] = {
+		"no pull",
+		"pull down",
+		"keeper",
+		"pull up"
+	};
+
+	pctldev = pctldev ? : state->ctrl;
+	pindesc = pctldev->desc->pins[offset];
+	ctl_reg = lpi_gpio_read(state, offset, LPI_GPIO_CFG_REG);
+	is_out = ctl_reg & LPI_GPIO_OE_MASK;
+
+	func = (ctl_reg & LPI_GPIO_FUNCTION_MASK) >> LPI_GPIO_FUNCTION_SHIFT;

func = FIELD_GET(LPI_GPIO_FUNCTION_MASK, ctl_reg);

+	drive = (ctl_reg & LPI_GPIO_OUT_STRENGTH_MASK) >>
+		 LPI_GPIO_OUT_STRENGTH_SHIFT;

drive = FIELD_GET(LPI_GPIO_OUT_STRENGTH_MASK, ctl_reg);

+	pull = (ctl_reg & LPI_GPIO_PULL_MASK) >> LPI_GPIO_PULL_SHIFT;

pull = FIELD_GET(LPI_GPIO_PULL_MASK, ctl_reg);

Make sense, will do it!


+
+	seq_printf(s, " %-8s: %-3s %d",
+		   pindesc.name, is_out ? "out" : "in", func);

This line doesn't need to be broken.


thanks,
srini

Regards,
Bjorn







