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memory: omap-gpmc: wait pin additions 

This patch introduces support for setting the wait-pin polarity as well
as using the same wait-pin for different CS regions.

The waitpin polarity can be configured via the WAITPIN<X>POLARITY bits
in the GPMC_CONFIG register. This is currently not supported by the
driver. This patch adds support for setting the required register bits
with the "ti,wait-pin-polarity" dt-property.

The wait-pin can also be shared between different CS regions for special
usecases. Therefore GPMC must keep track of wait-pin allocations, so it
knows that either GPMC itself or another driver has the ownership.

Signed-off-by: Benedikt Niedermayr <benedikt.niedermayr@siemens.com>
Link: https://lore.kernel.org/r/20221102133047.1654449-2-benedikt.niedermayr@siemens.com
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
This commit is contained in:
Benedikt Niedermayr 2022-11-02 14:30:46 +01:00 committed by Krzysztof Kozlowski
parent 3821e96a01
commit 89aed3cd5c
2 changed files with 117 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

122
drivers/memory/omap-gpmc.c
View File

@ -134,6 +134,7 @@
#define GPMC_CONFIG_DEV_SIZE 0x00000002
#define GPMC_CONFIG_DEV_TYPE 0x00000003
#define GPMC_CONFIG_WAITPINPOLARITY(pin) (BIT(pin) << 8)
#define GPMC_CONFIG1_WRAPBURST_SUPP (1 << 31)
#define GPMC_CONFIG1_READMULTIPLE_SUPP (1 << 30)
#define GPMC_CONFIG1_READTYPE_ASYNC (0 << 29)
@ -229,6 +230,12 @@ struct omap3_gpmc_regs {
struct gpmc_cs_config cs_context[GPMC_CS_NUM];
};
struct gpmc_waitpin {
u32 pin;
u32 polarity;
struct gpio_desc *desc;
};
struct gpmc_device {
struct device *dev;
int irq;
@ -236,6 +243,7 @@ struct gpmc_device {
struct gpio_chip gpio_chip;
struct notifier_block nb;
struct omap3_gpmc_regs context;
struct gpmc_waitpin *waitpins;
int nirqs;
unsigned int is_suspended:1;
struct resource *data;
@ -1035,6 +1043,62 @@ void gpmc_cs_free(int cs)
}
EXPORT_SYMBOL(gpmc_cs_free);
static bool gpmc_is_valid_waitpin(u32 waitpin)
{
return waitpin >= 0 && waitpin < gpmc_nr_waitpins;
}
static int gpmc_alloc_waitpin(struct gpmc_device *gpmc,
struct gpmc_settings *p)
{
int ret;
struct gpmc_waitpin *waitpin;
struct gpio_desc *waitpin_desc;
if (!gpmc_is_valid_waitpin(p->wait_pin))
return -EINVAL;
waitpin = &gpmc->waitpins[p->wait_pin];
if (!waitpin->desc) {
/* Reserve the GPIO for wait pin usage.
* GPIO polarity doesn't matter here. Wait pin polarity
* is set in GPMC_CONFIG register.
*/
waitpin_desc = gpiochip_request_own_desc(&gpmc->gpio_chip,
p->wait_pin, "WAITPIN",
GPIO_ACTIVE_HIGH,
GPIOD_IN);
ret = PTR_ERR(waitpin_desc);
if (IS_ERR(waitpin_desc) && ret != -EBUSY)
return ret;
/* New wait pin */
waitpin->desc = waitpin_desc;
waitpin->pin = p->wait_pin;
waitpin->polarity = p->wait_pin_polarity;
} else {
/* Shared wait pin */
if (p->wait_pin_polarity != waitpin->polarity ||
p->wait_pin != waitpin->pin) {
dev_err(gpmc->dev,
"shared-wait-pin: invalid configuration\n");
return -EINVAL;
}
dev_info(gpmc->dev, "shared wait-pin: %d\n", waitpin->pin);
}
return 0;
}
static void gpmc_free_waitpin(struct gpmc_device *gpmc,
int wait_pin)
{
if (gpmc_is_valid_waitpin(wait_pin))
gpiochip_free_own_desc(gpmc->waitpins[wait_pin].desc);
}
/**
* gpmc_configure - write request to configure gpmc
* @cmd: command type
@ -1886,6 +1950,17 @@ int gpmc_cs_program_settings(int cs, struct gpmc_settings *p)
gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, config1);
if (p->wait_pin_polarity != GPMC_WAITPINPOLARITY_INVALID) {
config1 = gpmc_read_reg(GPMC_CONFIG);
if (p->wait_pin_polarity == GPMC_WAITPINPOLARITY_ACTIVE_LOW)
config1 &= ~GPMC_CONFIG_WAITPINPOLARITY(p->wait_pin);
else if (p->wait_pin_polarity == GPMC_WAITPINPOLARITY_ACTIVE_HIGH)
config1 |= GPMC_CONFIG_WAITPINPOLARITY(p->wait_pin);
gpmc_write_reg(GPMC_CONFIG, config1);
}
return 0;
}
@ -1975,7 +2050,25 @@ void gpmc_read_settings_dt(struct device_node *np, struct gpmc_settings *p)
__func__);
}
p->wait_pin = GPMC_WAITPIN_INVALID;
p->wait_pin_polarity = GPMC_WAITPINPOLARITY_INVALID;
if (!of_property_read_u32(np, "gpmc,wait-pin", &p->wait_pin)) {
if (!gpmc_is_valid_waitpin(p->wait_pin)) {
pr_err("%s: Invalid wait-pin (%d)\n", __func__, p->wait_pin);
p->wait_pin = GPMC_WAITPIN_INVALID;
}
if (!of_property_read_u32(np, "ti,wait-pin-polarity",
&p->wait_pin_polarity)) {
if (p->wait_pin_polarity != GPMC_WAITPINPOLARITY_ACTIVE_HIGH &&
p->wait_pin_polarity != GPMC_WAITPINPOLARITY_ACTIVE_LOW) {
pr_err("%s: Invalid wait-pin-polarity (%d)\n",
__func__, p->wait_pin_polarity);
p->wait_pin_polarity = GPMC_WAITPINPOLARITY_INVALID;
}
}
p->wait_on_read = of_property_read_bool(np,
"gpmc,wait-on-read");
p->wait_on_write = of_property_read_bool(np,
@ -2080,7 +2173,6 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
const char *name;
int ret, cs;
u32 val;
struct gpio_desc *waitpin_desc = NULL;
struct gpmc_device *gpmc = platform_get_drvdata(pdev);
if (of_property_read_u32(child, "reg", &cs) < 0) {
@ -2208,17 +2300,9 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
/* Reserve wait pin if it is required and valid */
if (gpmc_s.wait_on_read || gpmc_s.wait_on_write) {
unsigned int wait_pin = gpmc_s.wait_pin;
waitpin_desc = gpiochip_request_own_desc(&gpmc->gpio_chip,
wait_pin, "WAITPIN",
GPIO_ACTIVE_HIGH,
GPIOD_IN);
if (IS_ERR(waitpin_desc)) {
dev_err(&pdev->dev, "invalid wait-pin: %d\n", wait_pin);
ret = PTR_ERR(waitpin_desc);
ret = gpmc_alloc_waitpin(gpmc, &gpmc_s);
if (ret < 0)
goto err;
}
}
gpmc_cs_show_timings(cs, "before gpmc_cs_program_settings");
@ -2260,7 +2344,7 @@ err_child_fail:
ret = -ENODEV;
err_cs:
gpiochip_free_own_desc(waitpin_desc);
gpmc_free_waitpin(gpmc, gpmc_s.wait_pin);
err:
gpmc_cs_free(cs);
@ -2489,7 +2573,7 @@ static int omap_gpmc_context_notifier(struct notifier_block *nb,
static int gpmc_probe(struct platform_device *pdev)
{
int rc;
int rc, i;
u32 l;
struct resource *res;
struct gpmc_device *gpmc;
@ -2545,6 +2629,15 @@ static int gpmc_probe(struct platform_device *pdev)
gpmc_nr_waitpins = GPMC_NR_WAITPINS;
}
gpmc->waitpins = devm_kzalloc(&pdev->dev,
gpmc_nr_waitpins * sizeof(struct gpmc_waitpin),
GFP_KERNEL);
if (!gpmc->waitpins)
return -ENOMEM;
for (i = 0; i < gpmc_nr_waitpins; i++)
gpmc->waitpins[i].pin = GPMC_WAITPIN_INVALID;
pm_runtime_enable(&pdev->dev);
pm_runtime_get_sync(&pdev->dev);
@ -2598,9 +2691,12 @@ gpio_init_failed:
static int gpmc_remove(struct platform_device *pdev)
{
int i;
struct gpmc_device *gpmc = platform_get_drvdata(pdev);
cpu_pm_unregister_notifier(&gpmc->nb);
for (i = 0; i < gpmc_nr_waitpins; i++)
gpmc_free_waitpin(gpmc, i);
gpmc_free_irq(gpmc);
gpmc_mem_exit();
pm_runtime_put_sync(&pdev->dev);

8
include/linux/platform_data/gpmc-omap.h
View File

@ -136,6 +136,13 @@ struct gpmc_device_timings {
#define GPMC_MUX_AAD 1 /* Addr-Addr-Data multiplex */
#define GPMC_MUX_AD 2 /* Addr-Data multiplex */
/* Wait pin polarity values */
#define GPMC_WAITPINPOLARITY_INVALID -1
#define GPMC_WAITPINPOLARITY_ACTIVE_LOW 0
#define GPMC_WAITPINPOLARITY_ACTIVE_HIGH 1
#define GPMC_WAITPIN_INVALID -1
struct gpmc_settings {
bool burst_wrap; /* enables wrap bursting */
bool burst_read; /* enables read page/burst mode */
@ -149,6 +156,7 @@ struct gpmc_settings {
u32 device_width; /* device bus width (8 or 16 bit) */
u32 mux_add_data; /* multiplex address & data */
u32 wait_pin; /* wait-pin to be used */
u32 wait_pin_polarity;
};
/* Data for each chip select */