Module: xenomai-3
Branch: wip/drivers
Commit: f2d77932c737e31a3c2abce81ba00436a60ed1f6
URL:
http://git.xenomai.org/?p=xenomai-3.git;a=commit;h=f2d77932c737e31a3c2abce81ba00436a60ed1f6
Author: Philippe Gerum <r...@xenomai.org>
Date: Tue Jun 28 09:58:10 2016 +0200
drivers/spi: enable GPIO-based chip select
---
kernel/drivers/spi/spi-device.c | 38 +++++++++++++++++++++-----------------
kernel/drivers/spi/spi-device.h | 1 +
kernel/drivers/spi/spi-master.c | 18 ++++++++++++++++--
3 files changed, 38 insertions(+), 19 deletions(-)
diff --git a/kernel/drivers/spi/spi-device.c b/kernel/drivers/spi/spi-device.c
index 62482b2..08cf9b0 100644
--- a/kernel/drivers/spi/spi-device.c
+++ b/kernel/drivers/spi/spi-device.c
@@ -43,22 +43,14 @@ int rtdm_spi_add_remote_slave(struct rtdm_spi_remote_slave
*slave,
slave->config.speed_hz = spi->max_speed_hz;
slave->config.mode = spi->mode;
slave->master = master;
- mutex_init(&slave->ctl_lock);
dev = &slave->dev;
dev->driver = &master->driver;
dev->label = kasprintf(GFP_KERNEL, "%s/slave%d.%%d",
dev_name(&kmaster->dev),
kmaster->bus_num);
- if (dev->label == NULL) {
- ret = -ENOMEM;
- goto fail_label;
- }
-
- dev->device_data = master;
- ret = rtdm_dev_register(dev);
- if (ret)
- goto fail_register;
+ if (dev->label == NULL)
+ return -ENOMEM;
if (gpio_is_valid(spi->cs_gpio))
slave->cs_gpio = spi->cs_gpio;
@@ -68,21 +60,30 @@ int rtdm_spi_add_remote_slave(struct rtdm_spi_remote_slave
*slave,
slave->cs_gpio = kmaster->cs_gpios[spi->chip_select];
}
- if (gpio_is_valid(slave->cs_gpio))
- dev_dbg(slave_to_kdev(slave), "using CS GPIO%d\n",
- slave->cs_gpio);
+ if (gpio_is_valid(slave->cs_gpio)) {
+ ret = gpio_request(slave->cs_gpio, dev->label);
+ if (ret)
+ goto fail;
+ slave->cs_gpiod = gpio_to_desc(slave->cs_gpio);
+ if (slave->cs_gpiod == NULL)
+ goto fail;
+ }
+
+ mutex_init(&slave->ctl_lock);
+
+ dev->device_data = master;
+ ret = rtdm_dev_register(dev);
+ if (ret)
+ goto fail;
rtdm_lock_get_irqsave(&master->lock, c);
list_add_tail(&slave->next, &master->slaves);
rtdm_lock_put_irqrestore(&master->lock, c);
return 0;
-
-fail_register:
+fail:
kfree(dev->label);
-fail_label:
-
return ret;
}
EXPORT_SYMBOL_GPL(rtdm_spi_add_remote_slave);
@@ -93,6 +94,9 @@ void rtdm_spi_remove_remote_slave(struct
rtdm_spi_remote_slave *slave)
struct rtdm_device *dev;
rtdm_lockctx_t c;
+ if (gpio_is_valid(slave->cs_gpio))
+ gpio_free(slave->cs_gpio);
+
mutex_destroy(&slave->ctl_lock);
rtdm_lock_get_irqsave(&master->lock, c);
list_del(&slave->next);
diff --git a/kernel/drivers/spi/spi-device.h b/kernel/drivers/spi/spi-device.h
index fcfca90..ee43c38 100644
--- a/kernel/drivers/spi/spi-device.h
+++ b/kernel/drivers/spi/spi-device.h
@@ -30,6 +30,7 @@ struct rtdm_spi_master;
struct rtdm_spi_remote_slave {
u8 chip_select;
int cs_gpio;
+ struct gpio_desc *cs_gpiod;
struct rtdm_device dev;
struct list_head next;
struct rtdm_spi_config config;
diff --git a/kernel/drivers/spi/spi-master.c b/kernel/drivers/spi/spi-master.c
index 132a3b9..fe2ee40 100644
--- a/kernel/drivers/spi/spi-master.c
+++ b/kernel/drivers/spi/spi-master.c
@@ -25,6 +25,7 @@
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/spi/spi.h>
+#include <linux/gpio.h>
#include "spi-master.h"
static inline
@@ -105,6 +106,7 @@ static int do_chip_select(struct rtdm_spi_remote_slave
*slave)
{ /* master->bus_lock held */
struct rtdm_spi_master *master = slave->master;
rtdm_lockctx_t c;
+ int state;
if (slave->config.speed_hz == 0)
return -EINVAL; /* Setup is missing. */
@@ -113,7 +115,11 @@ static int do_chip_select(struct rtdm_spi_remote_slave
*slave)
rtdm_lock_get_irqsave(&master->lock, c);
if (master->cs != slave) {
- master->ops->chip_select(slave, true);
+ if (gpio_is_valid(slave->cs_gpio)) {
+ state = !!(slave->config.mode & SPI_CS_HIGH);
+ gpiod_set_raw_value(slave->cs_gpiod, state);
+ } else
+ master->ops->chip_select(slave, true);
master->cs = slave;
}
@@ -126,10 +132,18 @@ static void do_chip_deselect(struct rtdm_spi_remote_slave
*slave)
{ /* master->bus_lock held */
struct rtdm_spi_master *master = slave->master;
rtdm_lockctx_t c;
+ int state;
rtdm_lock_get_irqsave(&master->lock, c);
- master->ops->chip_select(slave, false);
+
+ if (gpio_is_valid(slave->cs_gpio)) {
+ state = !(slave->config.mode & SPI_CS_HIGH);
+ gpiod_set_raw_value(slave->cs_gpiod, state);
+ } else
+ master->ops->chip_select(slave, false);
+
master->cs = NULL;
+
rtdm_lock_put_irqrestore(&master->lock, c);
}
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