[PATCH 1/2] powerpc/5200: Export port-config

[Eric Millbrandt]

Allow device drivers to safely modify port-config.  This allows device drivers
access to gpio pins to manually bit-bang slave devices.

Signed-off-by: Eric Millbrandt <emillbrandt at dekaresearch.com>
---
 arch/powerpc/include/asm/mpc52xx.h           |    2 +
 arch/powerpc/platforms/52xx/mpc52xx_common.c |   61 ++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/mpc52xx.h b/arch/powerpc/include/asm/mpc52xx.h
index b664ce7..ebc5a3b 100644
--- a/arch/powerpc/include/asm/mpc52xx.h
+++ b/arch/powerpc/include/asm/mpc52xx.h
@@ -274,7 +274,9 @@ extern void mpc52xx_declare_of_platform_devices(void);
 extern void mpc52xx_map_common_devices(void);
 extern int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv);
 extern unsigned int mpc52xx_get_xtal_freq(struct device_node *node);
+extern unsigned int mpc52xx_read_port_config(void);
 extern void mpc52xx_restart(char *cmd);
+extern int mpc52xx_write_port_config(u32 mux, int operation);

 /* mpc52xx_gpt.c */
 struct mpc52xx_gpt_priv;
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_common.c b/arch/powerpc/platforms/52xx/mpc52xx_common.c
index a46bad0..77c685a 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_common.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_common.c
@@ -37,6 +37,11 @@ static struct of_device_id mpc52xx_bus_ids[] __initdata = {
        {}
 };

+static struct of_device_id mpc52xx_gpio_simple[] = {
+       { .compatible = "fsl,mpc5200-gpio", },
+       {}
+};
+
 /*
  * This variable is mapped in mpc52xx_map_wdt() and used in mpc52xx_restart().
  * Permanent mapping is required because mpc52xx_restart() can be called
@@ -82,6 +87,15 @@ mpc5200_setup_xlb_arbiter(void)
        iounmap(xlb);
 }

+/*
+ * This variable is mapped in mpc52xx_write_port_config() and
+ * mpc52xx_read_port_config().  Permanent mapping is required because
+ * mpc52xx_map_and_lock_port_config() can be called from interrupt context
+ * while node mapping (which calls ioremap()) cannot be used at such point.
+ */
+static DEFINE_SPINLOCK(mpc52xx_port_config_lock);
+static u32 __iomem *port_config;
+
 /**
  * mpc52xx_declare_of_platform_devices: register internal devices and children
  *                                     of the localplus bus to the of_platform
@@ -117,6 +131,7 @@ void __init
 mpc52xx_map_common_devices(void)
 {
        struct device_node *np;
+       const u32 *regaddr;

        /* mpc52xx_wdt is mapped here and used in mpc52xx_restart,
         * possibly from a interrupt context. wdt is only implement
@@ -135,6 +150,13 @@ mpc52xx_map_common_devices(void)
        np = of_find_matching_node(NULL, mpc52xx_cdm_ids);
        mpc52xx_cdm = of_iomap(np, 0);
        of_node_put(np);
+
+       /* port_config register */
+       np = of_find_matching_node(NULL, mpc52xx_gpio_simple);
+       regaddr = of_get_address(np, 0, NULL, NULL);
+       port_config = ioremap((u32) of_translate_address(np, regaddr), 0x4);
+
+       of_node_put(np);
 }

 /**
@@ -233,3 +255,42 @@ mpc52xx_restart(char *cmd)

        while (1);
 }
+
+/**
+ * mpc52xx_write_port_config: Allow mutually exclusive access to the
+ * port_config register
+ *
+ * @newmux: value to write to port_config
+ * @operation: set to 0 for | or 1 for &
+ */
+int mpc52xx_write_port_config(u32 newmux, int operation)
+{
+       unsigned long flags;
+       u32 mux;
+
+       if (!port_config)
+               return -ENODEV;
+
+       spin_lock_irqsave(&mpc52xx_port_config_lock, flags);
+       mux = in_be32(port_config);
+       if (operation)
+               out_be32(port_config, mux & newmux);
+       else
+               out_be32(port_config, mux | newmux);
+       spin_unlock_irqrestore(&mpc52xx_port_config_lock, flags);
+
+       return 0;
+}
+EXPORT_SYMBOL(mpc52xx_write_port_config);
+
+/**
+ * mpc52xx_read_port_config: Return the value of port_config
+ */
+unsigned int mpc52xx_read_port_config(void)
+{
+       if (!port_config)
+               return -ENODEV;
+
+       return in_be32(port_config);
+}
+EXPORT_SYMBOL(mpc52xx_read_port_config);
--
1.6.3.1


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