spi: cadence: Allow for GPIO pins to be used as chipselects

[sfrench/cifs-2.6.git] / drivers / spi / spi-cadence.c

diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index 1c57ce64abba029a209fca1caf5495f294c5fa85..f0b5c7b91f37b0921410f599cf485a775152e691 100644 (file)
--- 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;