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clk: bcm2835: Do not use prediv with bcm2711's PLLs

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Contrary to previous SoCs, bcm2711 doesn't have a prescaler in the PLL
feedback loop. Bypass it by zeroing fb_prediv_mask when running on
bcm2711.

Note that, since the prediv configuration bits were re-purposed, this
was triggering miscalculations on all clocks hanging from the VPU clock,
notably the aux UART, making its output unintelligible.

Fixes: 42de9ad400 ("clk: bcm2835: Add BCM2711_CLOCK_EMMC2 support")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200730182619.23246-1-nsaenzjulienne@suse.de
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Nicolas Saenz Julienne 2020-07-30 20:26:19 +02:00 committed by Stephen Boyd
parent 2a08a9232b
commit f34e4651ce
1 changed files with 21 additions and 4 deletions
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25
drivers/clk/bcm/clk-bcm2835.c
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@ -314,6 +314,7 @@ struct bcm2835_cprman {
struct device *dev;
void __iomem *regs;
spinlock_t regs_lock; /* spinlock for all clocks */
unsigned int soc;
/*
* Real names of cprman clock parents looked up through
@ -526,6 +527,20 @@ static int bcm2835_pll_is_on(struct clk_hw *hw)
A2W_PLL_CTRL_PRST_DISABLE;
}
static u32 bcm2835_pll_get_prediv_mask(struct bcm2835_cprman *cprman,
const struct bcm2835_pll_data *data)
{
/*
* On BCM2711 there isn't a pre-divisor available in the PLL feedback
* loop. Bits 13:14 of ANA1 (PLLA,PLLB,PLLC,PLLD) have been re-purposed
* for to for VCO RANGE bits.
*/
if (cprman->soc & SOC_BCM2711)
return 0;
return data->ana->fb_prediv_mask;
}
static void bcm2835_pll_choose_ndiv_and_fdiv(unsigned long rate,
unsigned long parent_rate,
u32 *ndiv, u32 *fdiv)
@ -583,7 +598,7 @@ static unsigned long bcm2835_pll_get_rate(struct clk_hw *hw,
ndiv = (a2wctrl & A2W_PLL_CTRL_NDIV_MASK) >> A2W_PLL_CTRL_NDIV_SHIFT;
pdiv = (a2wctrl & A2W_PLL_CTRL_PDIV_MASK) >> A2W_PLL_CTRL_PDIV_SHIFT;
using_prediv = cprman_read(cprman, data->ana_reg_base + 4) &
data->ana->fb_prediv_mask;
bcm2835_pll_get_prediv_mask(cprman, data);
if (using_prediv) {
ndiv *= 2;
@ -666,6 +681,7 @@ static int bcm2835_pll_set_rate(struct clk_hw *hw,
struct bcm2835_pll *pll = container_of(hw, struct bcm2835_pll, hw);
struct bcm2835_cprman *cprman = pll->cprman;
const struct bcm2835_pll_data *data = pll->data;
u32 prediv_mask = bcm2835_pll_get_prediv_mask(cprman, data);
bool was_using_prediv, use_fb_prediv, do_ana_setup_first;
u32 ndiv, fdiv, a2w_ctl;
u32 ana[4];
@ -683,7 +699,7 @@ static int bcm2835_pll_set_rate(struct clk_hw *hw,
for (i = 3; i >= 0; i--)
ana[i] = cprman_read(cprman, data->ana_reg_base + i * 4);
was_using_prediv = ana[1] & data->ana->fb_prediv_mask;
was_using_prediv = ana[1] & prediv_mask;
ana[0] &= ~data->ana->mask0;
ana[0] |= data->ana->set0;
@ -693,10 +709,10 @@ static int bcm2835_pll_set_rate(struct clk_hw *hw,
ana[3] |= data->ana->set3;
if (was_using_prediv && !use_fb_prediv) {
ana[1] &= ~data->ana->fb_prediv_mask;
ana[1] &= ~prediv_mask;
do_ana_setup_first = true;
} else if (!was_using_prediv && use_fb_prediv) {
ana[1] |= data->ana->fb_prediv_mask;
ana[1] |= prediv_mask;
do_ana_setup_first = false;
} else {
do_ana_setup_first = true;
@ -2262,6 +2278,7 @@ static int bcm2835_clk_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, cprman);
cprman->onecell.num = asize;
cprman->soc = pdata->soc;
hws = cprman->onecell.hws;
for (i = 0; i < asize; i++) {