From: Moritz Fischer <mdf@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: linux-spi@vger.kernel.org, broonie@kernel.org,
moritz.fischer@ettus.com, alex.williams@ni.com,
Moritz Fischer <mdf@kernel.org>
Subject: [PATCH] spi: cadence: Allow for GPIO pins to be used as chipselects
Date: Tue, 25 Apr 2017 11:30:14 -0700 [thread overview]
Message-ID: <1493145014-3163-1-git-send-email-mdf@kernel.org> (raw)
This adds support for using GPIOs for chipselects as described by the
default dt-bindings.
Signed-off-by: Moritz Fischer <mdf@kernel.org>
---
Hi Mark,
I've tested this on my Zynq-7000 based system with
GPIO and non-gpio based chipselects mixed.
Thanks for your time,
Moritz
---
drivers/spi/spi-cadence.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index 1c57ce6..f0b5c7b 100644
--- a/drivers/spi/spi-cadence.c
+++ b/drivers/spi/spi-cadence.c
@@ -13,6 +13,7 @@
#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
@@ -127,6 +128,10 @@ struct cdns_spi {
u32 is_decoded_cs;
};
+struct cdns_spi_device_data {
+ bool gpio_requested;
+};
+
/* Macros for the SPI controller read/write */
static inline u32 cdns_spi_read(struct cdns_spi *xspi, u32 offset)
{
@@ -456,6 +461,64 @@ static int cdns_unprepare_transfer_hardware(struct spi_master *master)
return 0;
}
+static int cdns_spi_setup(struct spi_device *spi)
+{
+
+ int ret = -EINVAL;
+ struct cdns_spi_device_data *cdns_spi_data = spi_get_ctldata(spi);
+
+ /* this is a pin managed by the controller, leave it alone */
+ if (spi->cs_gpio == -ENOENT)
+ return 0;
+
+ /* this seems to be the first time we're here */
+ if (!cdns_spi_data) {
+ cdns_spi_data = kzalloc(sizeof(*cdns_spi_data), GFP_KERNEL);
+ if (!cdns_spi_data)
+ return -ENOMEM;
+ cdns_spi_data->gpio_requested = false;
+ spi_set_ctldata(spi, cdns_spi_data);
+ }
+
+ /* if we haven't done so, grab the gpio */
+ if (!cdns_spi_data->gpio_requested && gpio_is_valid(spi->cs_gpio)) {
+ ret = gpio_request_one(spi->cs_gpio,
+ (spi->mode & SPI_CS_HIGH) ?
+ GPIOF_OUT_INIT_LOW : GPIOF_OUT_INIT_HIGH,
+ dev_name(&spi->dev));
+ if (ret)
+ dev_err(&spi->dev, "can't request chipselect gpio %d\n",
+ spi->cs_gpio);
+ else
+ cdns_spi_data->gpio_requested = true;
+ } else {
+ if (gpio_is_valid(spi->cs_gpio)) {
+ int mode = ((spi->mode & SPI_CS_HIGH) ?
+ GPIOF_OUT_INIT_LOW : GPIOF_OUT_INIT_HIGH);
+
+ ret = gpio_direction_output(spi->cs_gpio, mode);
+ if (ret)
+ dev_err(&spi->dev, "chipselect gpio %d setup failed (%d)\n",
+ spi->cs_gpio, ret);
+ }
+ }
+
+ return ret;
+}
+
+static void cdns_spi_cleanup(struct spi_device *spi)
+{
+ struct cdns_spi_device_data *cdns_spi_data = spi_get_ctldata(spi);
+
+ if (cdns_spi_data) {
+ if (cdns_spi_data->gpio_requested)
+ gpio_free(spi->cs_gpio);
+ kfree(cdns_spi_data);
+ spi_set_ctldata(spi, NULL);
+ }
+
+}
+
/**
* cdns_spi_probe - Probe method for the SPI driver
* @pdev: Pointer to the platform_device structure
@@ -555,6 +618,8 @@ static int cdns_spi_probe(struct platform_device *pdev)
master->transfer_one = cdns_transfer_one;
master->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware;
master->set_cs = cdns_spi_chipselect;
+ master->setup = cdns_spi_setup;
+ master->cleanup = cdns_spi_cleanup;
master->auto_runtime_pm = true;
master->mode_bits = SPI_CPOL | SPI_CPHA;
--
2.7.4
next reply other threads:[~2017-04-25 18:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-25 18:30 Moritz Fischer [this message]
2017-04-26 14:50 ` Applied "spi: cadence: Allow for GPIO pins to be used as chipselects" to the spi tree Mark Brown
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