From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Kaehlcke Subject: Re: [PATCH 3/6] i2c: i2c-qcom-geni: Add interconnect support Date: Thu, 20 Feb 2020 16:24:00 -0800 Message-ID: <20200221002400.GD24720@google.com> References: <1581946205-27189-1-git-send-email-akashast@codeaurora.org> <1581946205-27189-4-git-send-email-akashast@codeaurora.org> <20200218224709.GF15781@google.com> <84a7d97a-4e10-5509-9c87-af8a545c7385@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: gregkh@linuxfoundation.org, agross@kernel.org, bjorn.andersson@linaro.org, wsa@the-dreams.de, broonie@kernel.org, mark.rutland@arm.com, robh+dt@kernel.org, linux-i2c@vger.kernel.org, linux-spi@vger.kernel.org, devicetree@vger.kernel.org, swboyd@chromium.org, mgautam@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org, dianders@chromium.org To: Akash Asthana Return-path: Content-Disposition: inline In-Reply-To: <84a7d97a-4e10-5509-9c87-af8a545c7385@codeaurora.org> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org Hi Akash, On Wed, Feb 19, 2020 at 07:17:44PM +0530, Akash Asthana wrote: > Hi Matthias, > > On 2/19/2020 4:17 AM, Matthias Kaehlcke wrote: > > On Mon, Feb 17, 2020 at 07:00:02PM +0530, Akash Asthana wrote: > > > Get the interconnect paths for I2C based Serial Engine device > > > and vote according to the bus speed of the driver. > > > > > > Signed-off-by: Akash Asthana > > > --- > > > drivers/i2c/busses/i2c-qcom-geni.c | 84 ++++++++++++++++++++++++++++++++++++-- > > > 1 file changed, 80 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c > > > index 17abf60c..5de10a1 100644 > > > --- a/drivers/i2c/busses/i2c-qcom-geni.c > > > +++ b/drivers/i2c/busses/i2c-qcom-geni.c > > > > > > static void geni_i2c_err_misc(struct geni_i2c_dev *gi2c) > > > { > > > u32 m_cmd = readl_relaxed(gi2c->se.base + SE_GENI_M_CMD0); > > > @@ -563,17 +601,34 @@ static int geni_i2c_probe(struct platform_device *pdev) > > > gi2c->adap.dev.of_node = pdev->dev.of_node; > > > strlcpy(gi2c->adap.name, "Geni-I2C", sizeof(gi2c->adap.name)); > > > + ret = geni_i2c_icc_get(&gi2c->se); > > > + if (ret) > > > + return ret; > > > + /* Set the bus quota to a reasonable value */ > > > + gi2c->se.avg_bw_core = Bps_to_icc(1000); > > > + gi2c->se.peak_bw_core = Bps_to_icc(CORE_2X_100_MHZ); > > > + gi2c->se.avg_bw_cpu = Bps_to_icc(1000); > > > + gi2c->se.peak_bw_cpu = Bps_to_icc(1000); > > > + gi2c->se.avg_bw_ddr = Bps_to_icc(gi2c->clk_freq_out); > > > + gi2c->se.peak_bw_ddr = Bps_to_icc(2 * gi2c->clk_freq_out); > > > + > > > + /* Vote for core clocks and CPU for register access */ > > > + icc_set_bw(gi2c->se.icc_path[GENI_TO_CORE], gi2c->se.avg_bw_core, > > > + gi2c->se.peak_bw_core); > > > + icc_set_bw(gi2c->se.icc_path[CPU_TO_GENI], gi2c->se.avg_bw_cpu, > > > + gi2c->se.peak_bw_cpu); > > error handling needed? > > I will add error handling for GENI_TO_CORE path in all the drivers. Will it > be okay if we don't handle errors for CPU_TO_GENI and GENI_TO_DDR path > > as CPU and DDR will be running at much higher frequency? It may still work, but you might never know that there was a problem. I would be inclined to check the return value of all invocations of icc_set_bw() - including runtime suspend/resume - and log a message if a problem is detected. For runtime suspend/resume it would probably be wise to use dev_err_ratelimited(), to avoid spamming the system log too much in case of a persistent problem. If others think that error checking all icc_set_bw() calls is overkill please speak up :) Thanks Matthias