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([82.78.167.145]) by smtp.gmail.com with ESMTPSA id f21-20020a05640214d500b0051e22660835sm5422415edx.46.2023.09.11.21.52.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Sep 2023 21:52:35 -0700 (PDT) From: Claudiu X-Google-Original-From: Claudiu To: geert+renesas@glider.be, mturquette@baylibre.com, sboyd@kernel.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, ulf.hansson@linaro.org, linus.walleij@linaro.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, magnus.damm@gmail.com, catalin.marinas@arm.com, will@kernel.org, prabhakar.mahadev-lad.rj@bp.renesas.com, biju.das.jz@bp.renesas.com, quic_bjorande@quicinc.com, arnd@arndb.de, konrad.dybcio@linaro.org, neil.armstrong@linaro.org, nfraprado@collabora.com, rafal@milecki.pl, wsa+renesas@sang-engineering.com Cc: linux-renesas-soc@vger.kernel.org, linux-clk@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, linux-gpio@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Claudiu Beznea Subject: [PATCH 09/37] clk: renesas: rzg2l: fix computation formula Date: Tue, 12 Sep 2023 07:51:29 +0300 Message-Id: <20230912045157.177966-10-claudiu.beznea.uj@bp.renesas.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230912045157.177966-1-claudiu.beznea.uj@bp.renesas.com> References: <20230912045157.177966-1-claudiu.beznea.uj@bp.renesas.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org From: Claudiu Beznea According to hardware manual of RZ/G2L (r01uh0914ej0130-rzg2l-rzg2lc.pdf) the computation formula for PLL rate is as follows: Fout = ((m + k/65536) * Fin) / (p * 2^s) and k has values in range [-32768, 32767]. Dividing k by 65536 with integer variables leads all the time to zero. Thus we may have slight differences b/w what has been set vs. what is displayed. Thus, get rid of this and decompose the formula before dividing k by 65536. Fixes: ef3c613ccd68a ("clk: renesas: Add CPG core wrapper for RZ/G2L SoC") Signed-off-by: Claudiu Beznea --- drivers/clk/renesas/rzg2l-cpg.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c index d0d086d6dc51..b391c9548421 100644 --- a/drivers/clk/renesas/rzg2l-cpg.c +++ b/drivers/clk/renesas/rzg2l-cpg.c @@ -696,18 +696,22 @@ static unsigned long rzg2l_cpg_pll_clk_recalc_rate(struct clk_hw *hw, struct pll_clk *pll_clk = to_pll(hw); struct rzg2l_cpg_priv *priv = pll_clk->priv; unsigned int val1, val2; - unsigned int mult = 1; - unsigned int div = 1; + unsigned int div; + u64 rate; + s16 kdiv; if (pll_clk->type != CLK_TYPE_SAM_PLL) return parent_rate; val1 = readl(priv->base + GET_REG_SAMPLL_CLK1(pll_clk->conf)); val2 = readl(priv->base + GET_REG_SAMPLL_CLK2(pll_clk->conf)); - mult = MDIV(val1) + KDIV(val1) / 65536; + kdiv = KDIV(val1); div = PDIV(val1) << SDIV(val2); - return DIV_ROUND_CLOSEST_ULL((u64)parent_rate * mult, div); + rate = (u64)MDIV(val1) * parent_rate; + rate += ((long long)parent_rate * kdiv) / 65536; + + return DIV_ROUND_CLOSEST_ULL(rate, div); } static const struct clk_ops rzg2l_cpg_pll_ops = {