clk: at91: fix programmable clock for sama5d2

The prescaler formula of the programmable clock has changed for sama5d2.
Update the driver accordingly.

Fixes: 3d9194a755f8 ("clk: at91: add sama5d2 PMC driver")
Cc: <stable@vger.kernel.org> # v4.20+
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
[nicolas.ferre@microchip.com: adapt the prescaler range,
		fix clk_programmable_recalc_rate, split patch]
Signed-off-by: Matthias Wieloch <matthias.wieloch@few-bauer.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
index 89d6f3736dbf605036e4eefb70efd2ef2ee4f386..f8edbb65eda3564cf99623c852fe474a93803123 100644 (file)
--- a/drivers/clk/at91/clk-programmable.c
+++ b/drivers/clk/at91/clk-programmable.c
@@ -20,8 +20,7 @@
 #define PROG_ID_MAX            7
 
 #define PROG_STATUS_MASK(id)   (1 << ((id) + 8))
-#define PROG_PRES_MASK         0x7
-#define PROG_PRES(layout, pckr)        ((pckr >> layout->pres_shift) & PROG_PRES_MASK)
+#define PROG_PRES(layout, pckr)        ((pckr >> layout->pres_shift) & layout->pres_mask)
 #define PROG_MAX_RM9200_CSS    3
 
 struct clk_programmable {
@@ -37,20 +36,29 @@ static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
                                                  unsigned long parent_rate)
 {
        struct clk_programmable *prog = to_clk_programmable(hw);
+       const struct clk_programmable_layout *layout = prog->layout;
        unsigned int pckr;
+       unsigned long rate;
 
        regmap_read(prog->regmap, AT91_PMC_PCKR(prog->id), &pckr);
 
-       return parent_rate >> PROG_PRES(prog->layout, pckr);
+       if (layout->is_pres_direct)
+               rate = parent_rate / (PROG_PRES(layout, pckr) + 1);
+       else
+               rate = parent_rate >> PROG_PRES(layout, pckr);
+
+       return rate;
 }
 
 static int clk_programmable_determine_rate(struct clk_hw *hw,
                                           struct clk_rate_request *req)
 {
+       struct clk_programmable *prog = to_clk_programmable(hw);
+       const struct clk_programmable_layout *layout = prog->layout;
        struct clk_hw *parent;
        long best_rate = -EINVAL;
        unsigned long parent_rate;
-       unsigned long tmp_rate;
+       unsigned long tmp_rate = 0;
        int shift;
        int i;
 
@@ -60,10 +68,18 @@ static int clk_programmable_determine_rate(struct clk_hw *hw,
                        continue;
 
                parent_rate = clk_hw_get_rate(parent);
-               for (shift = 0; shift < PROG_PRES_MASK; shift++) {
-                       tmp_rate = parent_rate >> shift;
-                       if (tmp_rate <= req->rate)
-                               break;
+               if (layout->is_pres_direct) {
+                       for (shift = 0; shift <= layout->pres_mask; shift++) {
+                               tmp_rate = parent_rate / (shift + 1);
+                               if (tmp_rate <= req->rate)
+                                       break;
+                       }
+               } else {
+                       for (shift = 0; shift < layout->pres_mask; shift++) {
+                               tmp_rate = parent_rate >> shift;
+                               if (tmp_rate <= req->rate)
+                                       break;
+                       }
                }
 
                if (tmp_rate > req->rate)
@@ -137,16 +153,23 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
        if (!div)
                return -EINVAL;
 
-       shift = fls(div) - 1;
+       if (layout->is_pres_direct) {
+               shift = div - 1;
 
-       if (div != (1 << shift))
-               return -EINVAL;
+               if (shift > layout->pres_mask)
+                       return -EINVAL;
+       } else {
+               shift = fls(div) - 1;
 
-       if (shift >= PROG_PRES_MASK)
-               return -EINVAL;
+               if (div != (1 << shift))
+                       return -EINVAL;
+
+               if (shift >= layout->pres_mask)
+                       return -EINVAL;
+       }
 
        regmap_update_bits(prog->regmap, AT91_PMC_PCKR(prog->id),
-                          PROG_PRES_MASK << layout->pres_shift,
+                          layout->pres_mask << layout->pres_shift,
                           shift << layout->pres_shift);
 
        return 0;
@@ -202,19 +225,25 @@ at91_clk_register_programmable(struct regmap *regmap,
 }
 
 const struct clk_programmable_layout at91rm9200_programmable_layout = {
+       .pres_mask = 0x7,
        .pres_shift = 2,
        .css_mask = 0x3,
        .have_slck_mck = 0,
+       .is_pres_direct = 0,
 };
 
 const struct clk_programmable_layout at91sam9g45_programmable_layout = {
+       .pres_mask = 0x7,
        .pres_shift = 2,
        .css_mask = 0x3,
        .have_slck_mck = 1,
+       .is_pres_direct = 0,
 };
 
 const struct clk_programmable_layout at91sam9x5_programmable_layout = {
+       .pres_mask = 0x7,
        .pres_shift = 4,
        .css_mask = 0x7,
        .have_slck_mck = 0,
+       .is_pres_direct = 0,
 };

diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index 672a79bda88c960d7655a600834705152f5a4eaf..a0e5ce9c9b9ea6981948ed102be4f8a870e6a99c 100644 (file)
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -71,9 +71,11 @@ struct clk_pll_characteristics {
 };
 
 struct clk_programmable_layout {
+       u8 pres_mask;
        u8 pres_shift;
        u8 css_mask;
        u8 have_slck_mck;
+       u8 is_pres_direct;
 };
 
 extern const struct clk_programmable_layout at91rm9200_programmable_layout;

diff --git a/drivers/clk/at91/sama5d2.c b/drivers/clk/at91/sama5d2.c
index 1f70cb164b06f310d867d54797dfd0d87be0a1d3..81943fac4537ef3c8e8d0f611a897b2dd6b8171f 100644 (file)
--- a/drivers/clk/at91/sama5d2.c
+++ b/drivers/clk/at91/sama5d2.c
@@ -125,6 +125,14 @@ static const struct {
          .pll = true },
 };
 
+static const struct clk_programmable_layout sama5d2_programmable_layout = {
+       .pres_mask = 0xff,
+       .pres_shift = 4,
+       .css_mask = 0x7,
+       .have_slck_mck = 0,
+       .is_pres_direct = 1,
+};
+
 static void __init sama5d2_pmc_setup(struct device_node *np)
 {
        struct clk_range range = CLK_RANGE(0, 0);
@@ -249,7 +257,7 @@ static void __init sama5d2_pmc_setup(struct device_node *np)
 
                hw = at91_clk_register_programmable(regmap, name,
                                                    parent_names, 6, i,
-                                                   &at91sam9x5_programmable_layout);
+                                                   &sama5d2_programmable_layout);
                if (IS_ERR(hw))
                        goto err_free;
        }