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phy: ti: am654-serdes: Support all clksel values
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Add support to select all 16 CLKSEL combinations that are shown in
"SerDes Reference Clock Distribution" in AM65 TRM.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
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Roger Quadros authored and Kishon Vijay Abraham I committed Apr 17, 2019
1 parent 71e2f5c commit 7e7b8ca
Showing 1 changed file with 83 additions and 49 deletions.
132 changes: 83 additions & 49 deletions drivers/phy/ti/phy-am654-serdes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -58,13 +58,14 @@

#define SERDES_NUM_CLOCKS 3

#define AM654_SERDES_CTRL_CLKSEL_MASK GENMASK(7, 4)
#define AM654_SERDES_CTRL_CLKSEL_SHIFT 4

struct serdes_am654_clk_mux {
struct clk_hw hw;
struct regmap *regmap;
unsigned int reg;
int *table;
u32 mask;
u8 shift;
int clk_id;
struct clk_init_data clk_data;
};

Expand Down Expand Up @@ -282,48 +283,105 @@ static const struct phy_ops ops = {
.owner = THIS_MODULE,
};

#define SERDES_NUM_MUX_COMBINATIONS 16

#define LICLK 0
#define EXT_REFCLK 1
#define RICLK 2

static const int
serdes_am654_mux_table[SERDES_NUM_MUX_COMBINATIONS][SERDES_NUM_CLOCKS] = {
/*
* Each combination maps to one of
* "Figure 12-1986. SerDes Reference Clock Distribution"
* in TRM.
*/
/* Parent of CMU refclk, Left output, Right output
* either of EXT_REFCLK, LICLK, RICLK
*/
{ EXT_REFCLK, EXT_REFCLK, EXT_REFCLK }, /* 0000 */
{ RICLK, EXT_REFCLK, EXT_REFCLK }, /* 0001 */
{ EXT_REFCLK, RICLK, LICLK }, /* 0010 */
{ RICLK, RICLK, EXT_REFCLK }, /* 0011 */
{ LICLK, EXT_REFCLK, EXT_REFCLK }, /* 0100 */
{ EXT_REFCLK, EXT_REFCLK, EXT_REFCLK }, /* 0101 */
{ LICLK, RICLK, LICLK }, /* 0110 */
{ EXT_REFCLK, RICLK, LICLK }, /* 0111 */
{ EXT_REFCLK, EXT_REFCLK, LICLK }, /* 1000 */
{ RICLK, EXT_REFCLK, LICLK }, /* 1001 */
{ EXT_REFCLK, RICLK, EXT_REFCLK }, /* 1010 */
{ RICLK, RICLK, EXT_REFCLK }, /* 1011 */
{ LICLK, EXT_REFCLK, LICLK }, /* 1100 */
{ EXT_REFCLK, EXT_REFCLK, LICLK }, /* 1101 */
{ LICLK, RICLK, EXT_REFCLK }, /* 1110 */
{ EXT_REFCLK, RICLK, EXT_REFCLK }, /* 1111 */
};

static u8 serdes_am654_clk_mux_get_parent(struct clk_hw *hw)
{
struct serdes_am654_clk_mux *mux = to_serdes_am654_clk_mux(hw);
unsigned int num_parents = clk_hw_get_num_parents(hw);
struct regmap *regmap = mux->regmap;
unsigned int reg = mux->reg;
unsigned int val;
int i;

regmap_read(regmap, reg, &val);
val >>= mux->shift;
val &= mux->mask;

for (i = 0; i < num_parents; i++)
if (mux->table[i] == val)
return i;

/*
* No parent? This should never happen!
* Verify if we set a valid parent in serdes_am654_clk_register()
*/
WARN(1, "Failed to find the parent of %s clock\n", hw->init->name);
val &= AM654_SERDES_CTRL_CLKSEL_MASK;
val >>= AM654_SERDES_CTRL_CLKSEL_SHIFT;

/* Make the parent lookup to fail */
return num_parents;
return serdes_am654_mux_table[val][mux->clk_id];
}

static int serdes_am654_clk_mux_set_parent(struct clk_hw *hw, u8 index)
{
struct serdes_am654_clk_mux *mux = to_serdes_am654_clk_mux(hw);
struct regmap *regmap = mux->regmap;
unsigned int reg = mux->reg;
int val;
int clk_id = mux->clk_id;
int parents[SERDES_NUM_CLOCKS];
const int *p;
u32 val;
int found, i;
int ret;

val = mux->table[index];
/* get existing setting */
regmap_read(regmap, reg, &val);
val &= AM654_SERDES_CTRL_CLKSEL_MASK;
val >>= AM654_SERDES_CTRL_CLKSEL_SHIFT;

for (i = 0; i < SERDES_NUM_CLOCKS; i++)
parents[i] = serdes_am654_mux_table[val][i];

/* change parent of this clock. others left intact */
parents[clk_id] = index;

/* Find the match */
for (val = 0; val < SERDES_NUM_MUX_COMBINATIONS; val++) {
p = serdes_am654_mux_table[val];
found = 1;
for (i = 0; i < SERDES_NUM_CLOCKS; i++) {
if (parents[i] != p[i]) {
found = 0;
break;
}
}

if (found)
break;
}

if (val == -1)
if (!found) {
/*
* This can never happen, unless we missed
* a valid combination in serdes_am654_mux_table.
*/
WARN(1, "Failed to find the parent of %s clock\n",
hw->init->name);
return -EINVAL;
}

val <<= mux->shift;
ret = regmap_update_bits(regmap, reg, mux->mask << mux->shift, val);
val <<= AM654_SERDES_CTRL_CLKSEL_SHIFT;
ret = regmap_update_bits(regmap, reg, AM654_SERDES_CTRL_CLKSEL_MASK,
val);

return ret;
}
Expand All @@ -333,21 +391,6 @@ static const struct clk_ops serdes_am654_clk_mux_ops = {
.get_parent = serdes_am654_clk_mux_get_parent,
};

static int mux_table[SERDES_NUM_CLOCKS][3] = {
/*
* The entries represent values for selecting between
* {left input, external reference clock, right input}
* Only one of Left Output or Right Output should be used since
* both left and right output clock uses the same bits and modifying
* one clock will impact the other.
*/
{ BIT(2), 0, BIT(0) }, /* Mux of CMU refclk */
{ -1, BIT(3), BIT(1) }, /* Mux of Left Output */
{ BIT(1), BIT(3) | BIT(1), -1 }, /* Mux of Right Output */
};

static int mux_mask[SERDES_NUM_CLOCKS] = { 0x5, 0xa, 0xa };

static int serdes_am654_clk_register(struct serdes_am654 *am654_phy,
const char *clock_name, int clock_num)
{
Expand Down Expand Up @@ -407,20 +450,11 @@ static int serdes_am654_clk_register(struct serdes_am654 *am654_phy,
init->num_parents = num_parents;
init->name = clock_name;

mux->table = mux_table[clock_num];
mux->regmap = regmap;
mux->reg = reg;
mux->shift = 4;
mux->mask = mux_mask[clock_num];
mux->clk_id = clock_num;
mux->hw.init = init;

/*
* setup a sane default so get_parent() call evaluates
* to a valid parent. Index 1 is the safest choice as
* the default as it is valid value for all of serdes's
* output clocks.
*/
serdes_am654_clk_mux_set_parent(&mux->hw, 1);
clk = devm_clk_register(dev, &mux->hw);
if (IS_ERR(clk))
return PTR_ERR(clk);
Expand Down

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