[ARM] 3578/1: AT91RM9200 Clock update

Patch from Andrew Victor

Some updates to the clock infrastructure for the AT91RM9200.

1. Hard-coded values replaced with names defined in at91rm9200_sys.h.
2. Added the four PIO clocks, which are enabled at startup.
3. At startup, disable all unused clocks.
4. Minor bugfix for usage counts associated with MCK. [Patch from David
Brownell]
5. Added at91_clock_associate() function to associate device & function
with a particular clock.  [Patch from David Brownell]

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 101 insertions, 20 deletions

diff --git a/arch/arm/mach-at91rm9200/clock.c b/arch/arm/mach-at91rm9200/clock.c
index 8b95467c6d61..30042d2bac5f 100644
--- a/arch/arm/mach-at91rm9200/clock.c
+++ b/arch/arm/mach-at91rm9200/clock.c
@@ -32,8 +32,6 @@
 
 #include "generic.h"
 
-#undef  DEBUG
-
 /*
  * There's a lot more which can be done with clocks, including cpufreq
  * integration, slow clock mode support (for system suspend), letting
@@ -41,7 +39,9 @@
  */
 
 struct clk {
-        const char      *name;
+        const char      *name;          /* unique clock name */
+        const char      *function;      /* function of the clock */
+        struct device   *dev;           /* device associated with function */
         unsigned long   rate_hz;
         struct clk      *parent;
         u32             pmc_mask;
@@ -71,15 +71,14 @@ static struct clk clk32k = {
 };
 static struct clk main_clk = {
         .name           = "main",
-        .pmc_mask       = 1 << 0,       /* in PMC_SR */
-        .users          = 1,
+        .pmc_mask       = AT91_PMC_MOSCS,       /* in PMC_SR */
         .id             = 1,
         .primary        = 1,
 };
 static struct clk plla = {
         .name           = "plla",
         .parent         = &main_clk,
-        .pmc_mask       = 1 << 1,       /* in PMC_SR */
+        .pmc_mask       = AT91_PMC_LOCKA,       /* in PMC_SR */
         .id             = 2,
         .primary        = 1,
         .pll            = 1,
@@ -105,7 +104,7 @@ static void pllb_mode(struct clk *clk, int is_on)
 static struct clk pllb = {
         .name           = "pllb",
         .parent         = &main_clk,
-        .pmc_mask       = 1 << 2,       /* in PMC_SR */
+        .pmc_mask       = AT91_PMC_LOCKB,       /* in PMC_SR */
         .mode           = pllb_mode,
         .id             = 3,
         .primary        = 1,
@@ -177,8 +176,7 @@ static struct clk pck3 = {
  */
 static struct clk mck = {
         .name           = "mck",
-        .pmc_mask       = 1 << 3,       /* in PMC_SR */
-        .users          = 1,            /* (must be) always on */
+        .pmc_mask       = AT91_PMC_MCKRDY,      /* in PMC_SR */
 };
 
 static void pmc_periph_mode(struct clk *clk, int is_on)
@@ -249,6 +247,30 @@ static struct clk spi_clk = {
         .pmc_mask       = 1 << AT91_ID_SPI,
         .mode           = pmc_periph_mode,
 };
+static struct clk pioA_clk = {
+        .name           = "pioA_clk",
+        .parent         = &mck,
+        .pmc_mask       = 1 << AT91_ID_PIOA,
+        .mode           = pmc_periph_mode,
+};
+static struct clk pioB_clk = {
+        .name           = "pioB_clk",
+        .parent         = &mck,
+        .pmc_mask       = 1 << AT91_ID_PIOB,
+        .mode           = pmc_periph_mode,
+};
+static struct clk pioC_clk = {
+        .name           = "pioC_clk",
+        .parent         = &mck,
+        .pmc_mask       = 1 << AT91_ID_PIOC,
+        .mode           = pmc_periph_mode,
+};
+static struct clk pioD_clk = {
+        .name           = "pioD_clk",
+        .parent         = &mck,
+        .pmc_mask       = 1 << AT91_ID_PIOD,
+        .mode           = pmc_periph_mode,
+};
 
 static struct clk *const clock_list[] = {
         /* four primary clocks -- MUST BE FIRST! */
@@ -279,21 +301,46 @@ static struct clk *const clock_list[] = {
         &udc_clk,
         &twi_clk,
         &spi_clk,
+        &pioA_clk,
+        &pioB_clk,
+        &pioC_clk,
+        &pioD_clk,
         // ssc0..ssc2
         // tc0..tc5
+        // irq0..irq6
         &ohci_clk,
         &ether_clk,
 };
 
 
+/*
+ * Associate a particular clock with a function (eg, "uart") and device.
+ * The drivers can then request the same 'function' with several different
+ * devices and not care about which clock name to use.
+ */
+void __init at91_clock_associate(const char *id, struct device *dev, const char *func)
+{
+        struct clk *clk = clk_get(NULL, id);
+
+        if (!dev || !clk || !IS_ERR(clk_get(dev, func)))
+                return;
+
+        clk->function = func;
+        clk->dev = dev;
+}
+
 /* clocks are all static for now; no refcounting necessary */
 struct clk *clk_get(struct device *dev, const char *id)
 {
         int i;
 
         for (i = 0; i < ARRAY_SIZE(clock_list); i++) {
-                if (strcmp(id, clock_list[i]->name) == 0)
-                        return clock_list[i];
+                struct clk *clk = clock_list[i];
+
+                if (strcmp(id, clk->name) == 0)
+                        return clk;
+                if (clk->function && (dev == clk->dev) && strcmp(id, clk->function) == 0)
+                        return clk;
         }
 
         return ERR_PTR(-ENOENT);
@@ -593,6 +640,30 @@ fail:
         return 0;
 }
 
+
+/*
+ * Several unused clocks may be active.  Turn them off.
+ */
+static void at91_periphclk_reset(void)
+{
+        unsigned long reg;
+        int i;
+
+        reg = at91_sys_read(AT91_PMC_PCSR);
+
+        for (i = 0; i < ARRAY_SIZE(clock_list); i++) {
+                struct clk      *clk = clock_list[i];
+
+                if (clk->mode != pmc_periph_mode)
+                        continue;
+
+                if (clk->users > 0)
+                        reg &= ~clk->pmc_mask;
+        }
+
+        at91_sys_write(AT91_PMC_PCDR, reg);
+}
+
 int __init at91_clock_init(unsigned long main_clock)
 {
         unsigned tmp, freq, mckr;
@@ -626,7 +697,6 @@ int __init at91_clock_init(unsigned long main_clock)
          */
         at91_pllb_usb_init = at91_pll_calc(main_clock, 48000000 * 2) | AT91_PMC_USB96M;
         pllb.rate_hz = at91_pll_rate(&pllb, main_clock, at91_pllb_usb_init);
-        at91_sys_write(AT91_PMC_PCDR, (1 << AT91_ID_UHP) | (1 << AT91_ID_UDP));
         at91_sys_write(AT91_PMC_SCDR, AT91_PMC_UHP | AT91_PMC_UDP);
         at91_sys_write(AT91_CKGR_PLLBR, 0);
         at91_sys_write(AT91_PMC_SCER, AT91_PMC_MCKUDP);
@@ -640,11 +710,13 @@ int __init at91_clock_init(unsigned long main_clock)
          */
         mckr = at91_sys_read(AT91_PMC_MCKR);
         mck.parent = clock_list[mckr & AT91_PMC_CSS];
-        mck.parent->users++;
         freq = mck.parent->rate_hz;
         freq /= (1 << ((mckr >> 2) & 3));               /* prescale */
         mck.rate_hz = freq / (1 + ((mckr >> 8) & 3));   /* mdiv */
 
+        /* MCK and CPU clock are "always on" */
+        clk_enable(&mck);
+
         printk("Clocks: CPU %u MHz, master %u MHz, main %u.%03u MHz\n",
                 freq / 1000000, (unsigned) mck.rate_hz / 1000000,
                 (unsigned) main_clock / 1000000,
@@ -663,19 +735,28 @@ int __init at91_clock_init(unsigned long main_clock)
                         continue;
 
                 pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
-                parent = clock_list[pckr & 3];
+                parent = clock_list[pckr & AT91_PMC_CSS];
                 clk->parent = parent;
                 clk->rate_hz = parent->rate_hz / (1 << ((pckr >> 2) & 3));
+
+                if (clk->users == 0) {
+                        /* not being used, so switch it off */
+                        at91_sys_write(AT91_PMC_SCDR, clk->pmc_mask);
+                }
         }
 #else
-        /* disable unused clocks */
+        /* disable all programmable clocks */
         at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK0 | AT91_PMC_PCK1 | AT91_PMC_PCK2 | AT91_PMC_PCK3);
-#endif  /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
+#endif
 
-        /* FIXME several unused clocks may still be active...  provide
-         * a CONFIG option to turn off all unused clocks at some point
-         * before driver init starts.
-         */
+        /* enable the PIO clocks */
+        clk_enable(&pioA_clk);
+        clk_enable(&pioB_clk);
+        clk_enable(&pioC_clk);
+        clk_enable(&pioD_clk);
+
+        /* disable all other unused peripheral clocks */
+        at91_periphclk_reset();
 
         return 0;
 }