diff mbox series

[v2,01/13] gpio: Add Elba SoC gpio driver for spi cs control

Message ID 20210329015938.20316-2-brad@pensando.io
State New
Headers show
Series [v2,01/13] gpio: Add Elba SoC gpio driver for spi cs control | expand

Commit Message

Brad Larson March 29, 2021, 1:59 a.m. UTC 
This GPIO driver is for the Pensando Elba SoC which
provides control of four chip selects on two SPI busses.

Signed-off-by: Brad Larson <brad@pensando.io>
---
 drivers/gpio/Kconfig           |   6 ++
 drivers/gpio/Makefile          |   1 +
 drivers/gpio/gpio-elba-spics.c | 114 +++++++++++++++++++++++++++++++++
 3 files changed, 121 insertions(+)
 create mode 100644 drivers/gpio/gpio-elba-spics.c

Comments

Andy Shevchenko March 29, 2021, 10:41 a.m. UTC | #1 
On Mon, Mar 29, 2021 at 5:01 AM Brad Larson <brad@pensando.io> wrote:
>
> This GPIO driver is for the Pensando Elba SoC which
> provides control of four chip selects on two SPI busses.

Same comments as per v1.
NAK from me until we get settled in that discussion.

...

> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Pensando Elba SoC SPI chip-select driver");

It's funny, you told it can't be a module and you add a dead code. Be
somehow consistent, please.
Serge Semin March 31, 2021, 6:10 p.m. UTC | #2 
On Sun, Mar 28, 2021 at 06:59:26PM -0700, Brad Larson wrote:
> This GPIO driver is for the Pensando Elba SoC which
> provides control of four chip selects on two SPI busses.
> 
> Signed-off-by: Brad Larson <brad@pensando.io>
> ---
>  drivers/gpio/Kconfig           |   6 ++
>  drivers/gpio/Makefile          |   1 +
>  drivers/gpio/gpio-elba-spics.c | 114 +++++++++++++++++++++++++++++++++
>  3 files changed, 121 insertions(+)
>  create mode 100644 drivers/gpio/gpio-elba-spics.c
> 
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index e3607ec4c2e8..4720459b24f5 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -241,6 +241,12 @@ config GPIO_EIC_SPRD
>  	help
>  	  Say yes here to support Spreadtrum EIC device.
>  
> +config GPIO_ELBA_SPICS
> +	bool "Pensando Elba SPI chip-select"
> +	depends on (ARCH_PENSANDO_ELBA_SOC || COMPILE_TEST)
> +	help
> +	  Say yes here to support the Penasndo Elba SoC SPI chip-select driver
> +
>  config GPIO_EM
>  	tristate "Emma Mobile GPIO"
>  	depends on (ARCH_EMEV2 || COMPILE_TEST) && OF_GPIO
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index c58a90a3c3b1..c5c7acad371b 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -54,6 +54,7 @@ obj-$(CONFIG_GPIO_DAVINCI)		+= gpio-davinci.o
>  obj-$(CONFIG_GPIO_DLN2)			+= gpio-dln2.o
>  obj-$(CONFIG_GPIO_DWAPB)		+= gpio-dwapb.o
>  obj-$(CONFIG_GPIO_EIC_SPRD)		+= gpio-eic-sprd.o
> +obj-$(CONFIG_GPIO_ELBA_SPICS)		+= gpio-elba-spics.o
>  obj-$(CONFIG_GPIO_EM)			+= gpio-em.o
>  obj-$(CONFIG_GPIO_EP93XX)		+= gpio-ep93xx.o
>  obj-$(CONFIG_GPIO_EXAR)			+= gpio-exar.o
> diff --git a/drivers/gpio/gpio-elba-spics.c b/drivers/gpio/gpio-elba-spics.c
> new file mode 100644
> index 000000000000..351bbaeea033
> --- /dev/null
> +++ b/drivers/gpio/gpio-elba-spics.c
> @@ -0,0 +1,114 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Pensando Elba SoC SPI chip select driver
> + *
> + * Copyright (c) 2020-2021, Pensando Systems Inc.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/gpio.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/init.h>
> +//#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +#include <linux/types.h>
> +
> +/*
> + * pin:	     3		  2	   |	   1		0
> + * bit:	 7------6------5------4----|---3------2------1------0
> + *	cs1  cs1_ovr  cs0  cs0_ovr |  cs1  cs1_ovr  cs0	 cs0_ovr
> + *		   ssi1		   |		 ssi0
> + */
> +#define SPICS_PIN_SHIFT(pin)	(2 * (pin))
> +#define SPICS_MASK(pin)		(0x3 << SPICS_PIN_SHIFT(pin))
> +#define SPICS_SET(pin, val)	((((val) << 1) | 0x1) << SPICS_PIN_SHIFT(pin))
> +
> +struct elba_spics_priv {
> +	void __iomem *base;
> +	spinlock_t lock;
> +	struct gpio_chip chip;
> +};
> +
> +static int elba_spics_get_value(struct gpio_chip *chip, unsigned int pin)
> +{
> +	return -ENOTSUPP;
> +}
> +
> +static void elba_spics_set_value(struct gpio_chip *chip,
> +		unsigned int pin, int value)
> +{
> +	struct elba_spics_priv *p = gpiochip_get_data(chip);
> +	unsigned long flags;
> +	u32 tmp;
> +
> +	/* select chip select from register */
> +	spin_lock_irqsave(&p->lock, flags);
> +	tmp = readl_relaxed(p->base);
> +	tmp = (tmp & ~SPICS_MASK(pin)) | SPICS_SET(pin, value);
> +	writel_relaxed(tmp, p->base);
> +	spin_unlock_irqrestore(&p->lock, flags);
> +}
> +
> +static int elba_spics_direction_input(struct gpio_chip *chip, unsigned int pin)
> +{
> +	return -ENOTSUPP;
> +}
> +
> +static int elba_spics_direction_output(struct gpio_chip *chip,
> +		unsigned int pin, int value)
> +{
> +	elba_spics_set_value(chip, pin, value);
> +	return 0;
> +}
> +
> +static int elba_spics_probe(struct platform_device *pdev)
> +{
> +	struct elba_spics_priv *p;
> +	struct resource *res;
> +	int ret = 0;
> +
> +	p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
> +	if (!p)
> +		return -ENOMEM;
> +

> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	p->base = devm_ioremap_resource(&pdev->dev, res);

In accordance with the DTS-node this is just a single register
0x307c2468-0x307c24C picked from some bigger block, which most likely
belongs to something like a system controller. PCIe node has got
another register from there "0x307c2480-0x307c2484/* MS CFG_WDT */",
and some BSM device too "0x307c2080-0x307c2084". Please consider using
syscon instead of directly requesting the resource here.

-Sergey

> +	if (IS_ERR(p->base))
> +		return PTR_ERR(p->base);
> +	spin_lock_init(&p->lock);
> +	platform_set_drvdata(pdev, p);
> +
> +	p->chip.ngpio = 4;	/* 2 cs pins for spi0, and 2 for spi1 */
> +	p->chip.base = -1;
> +	p->chip.direction_input = elba_spics_direction_input;
> +	p->chip.direction_output = elba_spics_direction_output;
> +	p->chip.get = elba_spics_get_value;
> +	p->chip.set = elba_spics_set_value;
> +	p->chip.label = dev_name(&pdev->dev);
> +	p->chip.parent = &pdev->dev;
> +	p->chip.owner = THIS_MODULE;
> +
> +	ret = devm_gpiochip_add_data(&pdev->dev, &p->chip, p);
> +	if (ret)
> +		dev_err(&pdev->dev, "unable to add gpio chip\n");
> +	return ret;
> +}
> +
> +static const struct of_device_id elba_spics_of_match[] = {
> +	{ .compatible = "pensando,elba-spics" },
> +	{}
> +};
> +
> +static struct platform_driver elba_spics_driver = {
> +	.probe = elba_spics_probe,
> +	.driver = {
> +		.name = "pensando-elba-spics",
> +		.of_match_table = elba_spics_of_match,
> +	},
> +};
> +module_platform_driver(elba_spics_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Pensando Elba SoC SPI chip-select driver");
> -- 
> 2.17.1
>
Brad Larson Aug. 23, 2021, 1:22 a.m. UTC | #3 
Hi Andy,

On Mon, Mar 29, 2021 at 3:41 AM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>

> On Mon, Mar 29, 2021 at 5:01 AM Brad Larson <brad@pensando.io> wrote:

> >

> > This GPIO driver is for the Pensando Elba SoC which

> > provides control of four chip selects on two SPI busses.

[...]
> > +MODULE_LICENSE("GPL v2");

> > +MODULE_DESCRIPTION("Pensando Elba SoC SPI chip-select driver");

>

> It's funny, you told it can't be a module and you add a dead code. Be

> somehow consistent, please.


Yes the code was not consistent with statement that the module cannot
being loadable in my reply.  I had not used builtin_platform_driver()
previously.  The updated patchset will be changed to this for the
driver.

-module_platform_driver(elba_spics_driver);
-
-MODULE_LICENSE("GPL v2");
-MODULE_DESCRIPTION("Elba SPI chip-select driver");
+builtin_platform_driver(elba_spics_driver);

where drivers/gpio/Kconfig could be changed to this

--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -241,10 +241,8 @@ config GPIO_EIC_SPRD
          Say yes here to support Spreadtrum EIC device.

 config GPIO_ELBA_SPICS
-       bool "Pensando Elba SPI chip-select"
+       def_bool y
        depends on ARCH_PENSANDO_ELBA_SOC || COMPILE_TEST
-       help
-         Say yes here to support the Pensando Elba SoC SPI chip-select driver

Regards,
Brad
Brad Larson Aug. 23, 2021, 1:24 a.m. UTC | #4 
Hi Sergey,

On Wed, Mar 31, 2021 at 11:10 AM Serge Semin <fancer.lancer@gmail.com> wrote:
>

> On Sun, Mar 28, 2021 at 06:59:26PM -0700, Brad Larson wrote:

> > This GPIO driver is for the Pensando Elba SoC which

> > provides control of four chip selects on two SPI busses.

[...]
> > +static int elba_spics_probe(struct platform_device *pdev)

> > +{

> > +     struct elba_spics_priv *p;

> > +     struct resource *res;

> > +     int ret = 0;

> > +

> > +     p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);

> > +     if (!p)

> > +             return -ENOMEM;

> > +

>

> > +     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

> > +     p->base = devm_ioremap_resource(&pdev->dev, res);

>

> In accordance with the DTS-node this is just a single register

> 0x307c2468-0x307c24C picked from some bigger block, which most likely

> belongs to something like a system controller. PCIe node has got

> another register from there "0x307c2480-0x307c2484/* MS CFG_WDT */",

> and some BSM device too "0x307c2080-0x307c2084". Please consider using

> syscon instead of directly requesting the resource here.

>

> -Sergey


I've looked into a few syscon based implementations which resulted in
a regressions to include Elba spi probe failure and host machine check
trying to perform PCIe access to Elba SoC.  I like the idea of
refactoring to use syscon but I don't have a functional solution to do
so.

Regards,
Brad
diff mbox series

Patch

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e3607ec4c2e8..4720459b24f5 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -241,6 +241,12 @@  config GPIO_EIC_SPRD
 	help
 	  Say yes here to support Spreadtrum EIC device.
 
+config GPIO_ELBA_SPICS
+	bool "Pensando Elba SPI chip-select"
+	depends on (ARCH_PENSANDO_ELBA_SOC || COMPILE_TEST)
+	help
+	  Say yes here to support the Penasndo Elba SoC SPI chip-select driver
+
 config GPIO_EM
 	tristate "Emma Mobile GPIO"
 	depends on (ARCH_EMEV2 || COMPILE_TEST) && OF_GPIO
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index c58a90a3c3b1..c5c7acad371b 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -54,6 +54,7 @@  obj-$(CONFIG_GPIO_DAVINCI)		+= gpio-davinci.o
 obj-$(CONFIG_GPIO_DLN2)			+= gpio-dln2.o
 obj-$(CONFIG_GPIO_DWAPB)		+= gpio-dwapb.o
 obj-$(CONFIG_GPIO_EIC_SPRD)		+= gpio-eic-sprd.o
+obj-$(CONFIG_GPIO_ELBA_SPICS)		+= gpio-elba-spics.o
 obj-$(CONFIG_GPIO_EM)			+= gpio-em.o
 obj-$(CONFIG_GPIO_EP93XX)		+= gpio-ep93xx.o
 obj-$(CONFIG_GPIO_EXAR)			+= gpio-exar.o
diff --git a/drivers/gpio/gpio-elba-spics.c b/drivers/gpio/gpio-elba-spics.c
new file mode 100644
index 000000000000..351bbaeea033
--- /dev/null
+++ b/drivers/gpio/gpio-elba-spics.c
@@ -0,0 +1,114 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Pensando Elba SoC SPI chip select driver
+ *
+ * Copyright (c) 2020-2021, Pensando Systems Inc.
+ */
+
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/init.h>
+//#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+/*
+ * pin:	     3		  2	   |	   1		0
+ * bit:	 7------6------5------4----|---3------2------1------0
+ *	cs1  cs1_ovr  cs0  cs0_ovr |  cs1  cs1_ovr  cs0	 cs0_ovr
+ *		   ssi1		   |		 ssi0
+ */
+#define SPICS_PIN_SHIFT(pin)	(2 * (pin))
+#define SPICS_MASK(pin)		(0x3 << SPICS_PIN_SHIFT(pin))
+#define SPICS_SET(pin, val)	((((val) << 1) | 0x1) << SPICS_PIN_SHIFT(pin))
+
+struct elba_spics_priv {
+	void __iomem *base;
+	spinlock_t lock;
+	struct gpio_chip chip;
+};
+
+static int elba_spics_get_value(struct gpio_chip *chip, unsigned int pin)
+{
+	return -ENOTSUPP;
+}
+
+static void elba_spics_set_value(struct gpio_chip *chip,
+		unsigned int pin, int value)
+{
+	struct elba_spics_priv *p = gpiochip_get_data(chip);
+	unsigned long flags;
+	u32 tmp;
+
+	/* select chip select from register */
+	spin_lock_irqsave(&p->lock, flags);
+	tmp = readl_relaxed(p->base);
+	tmp = (tmp & ~SPICS_MASK(pin)) | SPICS_SET(pin, value);
+	writel_relaxed(tmp, p->base);
+	spin_unlock_irqrestore(&p->lock, flags);
+}
+
+static int elba_spics_direction_input(struct gpio_chip *chip, unsigned int pin)
+{
+	return -ENOTSUPP;
+}
+
+static int elba_spics_direction_output(struct gpio_chip *chip,
+		unsigned int pin, int value)
+{
+	elba_spics_set_value(chip, pin, value);
+	return 0;
+}
+
+static int elba_spics_probe(struct platform_device *pdev)
+{
+	struct elba_spics_priv *p;
+	struct resource *res;
+	int ret = 0;
+
+	p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	p->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(p->base))
+		return PTR_ERR(p->base);
+	spin_lock_init(&p->lock);
+	platform_set_drvdata(pdev, p);
+
+	p->chip.ngpio = 4;	/* 2 cs pins for spi0, and 2 for spi1 */
+	p->chip.base = -1;
+	p->chip.direction_input = elba_spics_direction_input;
+	p->chip.direction_output = elba_spics_direction_output;
+	p->chip.get = elba_spics_get_value;
+	p->chip.set = elba_spics_set_value;
+	p->chip.label = dev_name(&pdev->dev);
+	p->chip.parent = &pdev->dev;
+	p->chip.owner = THIS_MODULE;
+
+	ret = devm_gpiochip_add_data(&pdev->dev, &p->chip, p);
+	if (ret)
+		dev_err(&pdev->dev, "unable to add gpio chip\n");
+	return ret;
+}
+
+static const struct of_device_id elba_spics_of_match[] = {
+	{ .compatible = "pensando,elba-spics" },
+	{}
+};
+
+static struct platform_driver elba_spics_driver = {
+	.probe = elba_spics_probe,
+	.driver = {
+		.name = "pensando-elba-spics",
+		.of_match_table = elba_spics_of_match,
+	},
+};
+module_platform_driver(elba_spics_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Pensando Elba SoC SPI chip-select driver");