serial: sh-sci: Handle GPIO function requests.

This adds initial support for requesting the various GPIO functions
necessary for certain ports. This just plugs in dumb request/free logic,
but serves as a building block for migrating off of the ->init_pins mess
to a wholly gpiolib backed solution (primarily parts with external
RTS/CTS pins, but will also allow us to clean up RXD pin testing).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 69 insertions, 2 deletions

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 761a800cb483..9e62349b3d9f 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -50,6 +50,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
+#include <linux/gpio.h>
 
 #ifdef CONFIG_SUPERH
 #include <asm/sh_bios.h>
@@ -73,6 +74,7 @@ struct sci_port {
         struct clk              *fclk;
 
         char                    *irqstr[SCIx_NR_IRQS];
+        char                    *gpiostr[SCIx_NR_FNS];
 
         struct dma_chan                 *chan_tx;
         struct dma_chan                 *chan_rx;
@@ -1105,6 +1107,67 @@ static void sci_free_irq(struct sci_port *port)
         }
 }
 
+static const char *sci_gpio_names[SCIx_NR_FNS] = {
+        "sck", "rxd", "txd", "cts", "rts",
+};
+
+static const char *sci_gpio_str(unsigned int index)
+{
+        return sci_gpio_names[index];
+}
+
+static void __devinit sci_init_gpios(struct sci_port *port)
+{
+        struct uart_port *up = &port->port;
+        int i;
+
+        if (!port->cfg)
+                return;
+
+        for (i = 0; i < SCIx_NR_FNS; i++) {
+                const char *desc;
+                int ret;
+
+                if (!port->cfg->gpios[i])
+                        continue;
+
+                desc = sci_gpio_str(i);
+
+                port->gpiostr[i] = kasprintf(GFP_KERNEL, "%s:%s",
+                                             dev_name(up->dev), desc);
+
+                /*
+                 * If we've failed the allocation, we can still continue
+                 * on with a NULL string.
+                 */
+                if (!port->gpiostr[i])
+                        dev_notice(up->dev, "%s string allocation failure\n",
+                                   desc);
+
+                ret = gpio_request(port->cfg->gpios[i], port->gpiostr[i]);
+                if (unlikely(ret != 0)) {
+                        dev_notice(up->dev, "failed %s gpio request\n", desc);
+
+                        /*
+                         * If we can't get the GPIO for whatever reason,
+                         * no point in keeping the verbose string around.
+                         */
+                        kfree(port->gpiostr[i]);
+                }
+        }
+}
+
+static void sci_free_gpios(struct sci_port *port)
+{
+        int i;
+
+        for (i = 0; i < SCIx_NR_FNS; i++)
+                if (port->cfg->gpios[i]) {
+                        gpio_free(port->cfg->gpios[i]);
+                        kfree(port->gpiostr[i]);
+                }
+}
+
 static unsigned int sci_tx_empty(struct uart_port *port)
 {
         unsigned short status = sci_in(port, SCxSR);
@@ -1962,6 +2025,8 @@ static int __devinit sci_init_single(struct platform_device *dev,
         struct uart_port *port = &sci_port->port;
         int ret;
 
+        sci_port->cfg   = p;
+
         port->ops       = &sci_uart_ops;
         port->iotype    = UPIO_MEM;
         port->line      = index;
@@ -2007,6 +2072,8 @@ static int __devinit sci_init_single(struct platform_device *dev,
 
                 port->dev = &dev->dev;
 
+                sci_init_gpios(sci_port);
+
                 pm_runtime_irq_safe(&dev->dev);
                 pm_runtime_enable(&dev->dev);
         }
@@ -2041,8 +2108,6 @@ static int __devinit sci_init_single(struct platform_device *dev,
                 p->error_mask |= (1 << p->overrun_bit);
         }
 
-        sci_port->cfg           = p;
-
         port->mapbase           = p->mapbase;
         port->type              = p->type;
         port->flags             = p->flags;
@@ -2249,6 +2314,8 @@ static int sci_remove(struct platform_device *dev)
         cpufreq_unregister_notifier(&port->freq_transition,
                                     CPUFREQ_TRANSITION_NOTIFIER);
 
+        sci_free_gpios(port);
+
         uart_remove_one_port(&sci_uart_driver, &port->port);
 
         clk_put(port->iclk);