1 files changed, 83 insertions, 18 deletions

diff --git a/drivers/spi/spi_gpio.c b/drivers/spi/spi_gpio.c
index 82b480cc9637..e24a63498acb 100644
--- a/drivers/spi/spi_gpio.c
+++ b/drivers/spi/spi_gpio.c
@@ -167,6 +167,44 @@ static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,
         return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
 }
 
+/*
+ * These functions do not call setmosi or getmiso if respective flag
+ * (SPI_MASTER_NO_RX or SPI_MASTER_NO_TX) is set, so they are safe to
+ * call when such pin is not present or defined in the controller.
+ * A separate set of callbacks is defined to get highest possible
+ * speed in the generic case (when both MISO and MOSI lines are
+ * available), as optimiser will remove the checks when argument is
+ * constant.
+ */
+
+static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi,
+                unsigned nsecs, u32 word, u8 bits)
+{
+        unsigned flags = spi->master->flags;
+        return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
+}
+
+static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,
+                unsigned nsecs, u32 word, u8 bits)
+{
+        unsigned flags = spi->master->flags;
+        return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
+}
+
+static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,
+                unsigned nsecs, u32 word, u8 bits)
+{
+        unsigned flags = spi->master->flags;
+        return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
+}
+
+static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,
+                unsigned nsecs, u32 word, u8 bits)
+{
+        unsigned flags = spi->master->flags;
+        return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
+}
+
 /*----------------------------------------------------------------------*/
 
 static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
@@ -232,19 +270,30 @@ static int __init spi_gpio_alloc(unsigned pin, const char *label, bool is_in)
 }
 
 static int __init
-spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label)
+spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label,
+        u16 *res_flags)
 {
         int value;
 
         /* NOTE:  SPI_*_GPIO symbols may reference "pdata" */
 
-        value = spi_gpio_alloc(SPI_MOSI_GPIO, label, false);
-        if (value)
-                goto done;
+        if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI) {
+                value = spi_gpio_alloc(SPI_MOSI_GPIO, label, false);
+                if (value)
+                        goto done;
+        } else {
+                /* HW configuration without MOSI pin */
+                *res_flags |= SPI_MASTER_NO_TX;
+        }
 
-        value = spi_gpio_alloc(SPI_MISO_GPIO, label, true);
-        if (value)
-                goto free_mosi;
+        if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO) {
+                value = spi_gpio_alloc(SPI_MISO_GPIO, label, true);
+                if (value)
+                        goto free_mosi;
+        } else {
+                /* HW configuration without MISO pin */
+                *res_flags |= SPI_MASTER_NO_RX;
+        }
 
         value = spi_gpio_alloc(SPI_SCK_GPIO, label, false);
         if (value)
@@ -253,9 +302,11 @@ spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label)
         goto done;
 
 free_miso:
-        gpio_free(SPI_MISO_GPIO);
+        if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
+                gpio_free(SPI_MISO_GPIO);
 free_mosi:
-        gpio_free(SPI_MOSI_GPIO);
+        if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
+                gpio_free(SPI_MOSI_GPIO);
 done:
         return value;
 }
@@ -266,6 +317,7 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
         struct spi_master               *master;
         struct spi_gpio                 *spi_gpio;
         struct spi_gpio_platform_data   *pdata;
+        u16 master_flags = 0;
 
         pdata = pdev->dev.platform_data;
 #ifdef GENERIC_BITBANG
@@ -273,7 +325,7 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
                 return -ENODEV;
 #endif
 
-        status = spi_gpio_request(pdata, dev_name(&pdev->dev));
+        status = spi_gpio_request(pdata, dev_name(&pdev->dev), &master_flags);
         if (status < 0)
                 return status;
 
@@ -289,6 +341,7 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
         if (pdata)
                 spi_gpio->pdata = *pdata;
 
+        master->flags = master_flags;
         master->bus_num = pdev->id;
         master->num_chipselect = SPI_N_CHIPSEL;
         master->setup = spi_gpio_setup;
@@ -296,10 +349,18 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
 
         spi_gpio->bitbang.master = spi_master_get(master);
         spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
-        spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
-        spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;
-        spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;
-        spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;
+
+        if ((master_flags & (SPI_MASTER_NO_RX | SPI_MASTER_NO_RX)) == 0) {
+                spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
+                spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;
+                spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;
+                spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;
+        } else {
+                spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;
+                spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1;
+                spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2;
+                spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;
+        }
         spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer;
         spi_gpio->bitbang.flags = SPI_CS_HIGH;
 
@@ -307,8 +368,10 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
         if (status < 0) {
                 spi_master_put(spi_gpio->bitbang.master);
 gpio_free:
-                gpio_free(SPI_MISO_GPIO);
-                gpio_free(SPI_MOSI_GPIO);
+                if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
+                        gpio_free(SPI_MISO_GPIO);
+                if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
+                        gpio_free(SPI_MOSI_GPIO);
                 gpio_free(SPI_SCK_GPIO);
                 spi_master_put(master);
         }
@@ -331,8 +394,10 @@ static int __exit spi_gpio_remove(struct platform_device *pdev)
 
         platform_set_drvdata(pdev, NULL);
 
-        gpio_free(SPI_MISO_GPIO);
-        gpio_free(SPI_MOSI_GPIO);
+        if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
+                gpio_free(SPI_MISO_GPIO);
+        if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
+                gpio_free(SPI_MOSI_GPIO);
         gpio_free(SPI_SCK_GPIO);
 
         return status;