| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 72/92] clk: qcom: fix RCG M/N counter configuration | Date | Sat, 2 May 2015 21:03:27 +0200 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Archit Taneja <architt@codeaurora.org>
commit 0b21503dbbfa669dbd847b33578d4041513cddb2 upstream.
Currently, a RCG's M/N counter (used for fraction division) is set to either 'bypass' (counter disabled) or 'dual edge' (counter enabled) based on whether the corresponding rcg struct has a mnd field specified and a non-zero N.
In the case where M and N are the same value, the M/N counter is still enabled by code even though no division takes place. Leaving the RCG in such a state can result in improper behavior. This was observed with the DSI pixel clock RCG when M and N were both set to 1.
Add an additional check (M != N) to enable the M/N counter only when it's needed for fraction division.
Signed-off-by: Archit Taneja <architt@codeaurora.org> Fixes: bcd61c0f535a (clk: qcom: Add support for root clock generators (RCGs)) Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/clk/qcom/clk-rcg2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/clk/qcom/clk-rcg2.c +++ b/drivers/clk/qcom/clk-rcg2.c @@ -257,7 +257,7 @@ static int __clk_rcg2_set_rate(struct cl mask |= CFG_SRC_SEL_MASK | CFG_MODE_MASK; cfg = f->pre_div << CFG_SRC_DIV_SHIFT; cfg |= rcg->parent_map[f->src] << CFG_SRC_SEL_SHIFT; - if (rcg->mnd_width && f->n) + if (rcg->mnd_width && f->n && (f->m != f->n)) cfg |= CFG_MODE_DUAL_EDGE; ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG, mask, cfg);
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