lkml.org 
[lkml]   [2020]   [Jul]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 05/18] clk: at91: sam9x60-pll: check fcore against ranges
Date
According to datasheet the range of 600-1200MHz is for the
frequency generated by the fractional part of the PLL (namely
Fcorepllck according to datasheet). With this in mind the output
range of the PLL itself (fractional + div), taking into account
that the divider is 8 bits wide, is 600/256-1200Hz=2.3-1200MHz.

Fixes: a436c2a447e59 ("clk: at91: add sam9x60 PLL driver")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
drivers/clk/at91/clk-sam9x60-pll.c | 12 +++++++++++-
drivers/clk/at91/sam9x60.c | 2 +-
2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/at91/clk-sam9x60-pll.c b/drivers/clk/at91/clk-sam9x60-pll.c
index 4b7b6c435d4e..a933abebfbaf 100644
--- a/drivers/clk/at91/clk-sam9x60-pll.c
+++ b/drivers/clk/at91/clk-sam9x60-pll.c
@@ -21,6 +21,9 @@
#define UPLL_DIV 2
#define PLL_MUL_MAX (FIELD_GET(PMC_PLL_CTRL1_MUL_MSK, UINT_MAX) + 1)

+#define FCORE_MIN (600000000)
+#define FCORE_MAX (1200000000)
+
#define PLL_MAX_ID 1

struct sam9x60_pll {
@@ -168,6 +171,7 @@ static long sam9x60_pll_get_best_div_mul(struct sam9x60_pll *pll,
unsigned long bestdiv = 0;
unsigned long bestmul = 0;
unsigned long bestfrac = 0;
+ u64 fcore = 0;

if (rate < characteristics->output[0].min ||
rate > characteristics->output[0].max)
@@ -212,6 +216,11 @@ static long sam9x60_pll_get_best_div_mul(struct sam9x60_pll *pll,
remainder = rate - tmprate;
}

+ fcore = parent_rate * (tmpmul + 1) +
+ ((u64)parent_rate * tmpfrac >> 22);
+ if (fcore < FCORE_MIN || fcore > FCORE_MAX)
+ continue;
+
/*
* Compare the remainder with the best remainder found until
* now and elect a new best multiplier/divider pair if the
@@ -231,7 +240,8 @@ static long sam9x60_pll_get_best_div_mul(struct sam9x60_pll *pll,
}

/* Check if bestrate is a valid output rate */
- if (bestrate < characteristics->output[0].min ||
+ if (fcore < FCORE_MIN || fcore > FCORE_MAX ||
+ bestrate < characteristics->output[0].min ||
bestrate > characteristics->output[0].max)
return -ERANGE;

diff --git a/drivers/clk/at91/sam9x60.c b/drivers/clk/at91/sam9x60.c
index 3e20aa68259f..633891b98d43 100644
--- a/drivers/clk/at91/sam9x60.c
+++ b/drivers/clk/at91/sam9x60.c
@@ -22,7 +22,7 @@ static const struct clk_master_layout sam9x60_master_layout = {
};

static const struct clk_range plla_outputs[] = {
- { .min = 300000000, .max = 600000000 },
+ { .min = 2343750, .max = 1200000000 },
};

static const struct clk_pll_characteristics plla_characteristics = {
--
2.7.4
\
 
 \ /
  Last update: 2020-07-22 09:39    [W:0.238 / U:0.284 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site