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From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Wed, 14 Jun 2023 15:14:26 +0300
Message-ID: <CAA8EJppY1Ff+zLF4PDxxTzpVj25VKCK9z+is_M0VaTi1iahbBw@mail.gmail.com>
Subject: Re: [PATCH V4 2/4] clk: qcom: camcc-sm8550: Add camera clock
 controller driver for SM8550
To:     Jagadeesh Kona <quic_jkona@quicinc.com>
Cc:     Andy Gross <agross@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>,
        linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Taniya Das <quic_tdas@quicinc.com>,
        Satya Priya Kakitapalli <quic_skakitap@quicinc.com>,
        Imran Shaik <quic_imrashai@quicinc.com>,
        Ajit Pandey <quic_ajipan@quicinc.com>
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On Wed, 14 Jun 2023 at 14:55, Jagadeesh Kona <quic_jkona@quicinc.com> wrote:
>
>
>
> On 6/9/2023 9:52 PM, Dmitry Baryshkov wrote:
> > On Fri, 9 Jun 2023 at 14:52, Jagadeesh Kona <quic_jkona@quicinc.com> wrote:
> >>
> >> Add support for the camera clock controller for camera clients to be
> >> able to request for camcc clocks on SM8550 platform.
> >>
> >> Co-developed-by: Taniya Das <quic_tdas@quicinc.com>
> >> Signed-off-by: Taniya Das <quic_tdas@quicinc.com>
> >> Signed-off-by: Jagadeesh Kona <quic_jkona@quicinc.com>
> >> ---
> >> Changes since V3:
> >>   - No changes
> >> Changes since V2:
> >>   - No changes
> >> Changes since V1:
> >>   - Sorted the PLL names in proper order
> >>   - Updated all PLL configurations to lower case hex
> >>   - Reused evo ops instead of adding new ops for ole pll
> >>   - Moved few clocks to separate patch to fix patch too long error
> >>
> >>   drivers/clk/qcom/Kconfig        |    7 +
> >>   drivers/clk/qcom/Makefile       |    1 +
> >>   drivers/clk/qcom/camcc-sm8550.c | 3405 +++++++++++++++++++++++++++++++
> >>   3 files changed, 3413 insertions(+)
> >>   create mode 100644 drivers/clk/qcom/camcc-sm8550.c
> >>
> >> diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
> >> index 9cd1f05d436b..85efed78dc9a 100644
> >> --- a/drivers/clk/qcom/Kconfig
> >> +++ b/drivers/clk/qcom/Kconfig
> >> @@ -756,6 +756,13 @@ config SM_CAMCC_8450
> >>            Support for the camera clock controller on SM8450 devices.
> >>            Say Y if you want to support camera devices and camera functionality.
> >>
> >> +config SM_CAMCC_8550
> >> +       tristate "SM8550 Camera Clock Controller"
> >> +       select SM_GCC_8550
> >> +       help
> >> +         Support for the camera clock controller on SM8550 devices.
> >> +         Say Y if you want to support camera devices and camera functionality.
> >> +
> >>   config SM_DISPCC_6115
> >>          tristate "SM6115 Display Clock Controller"
> >>          depends on ARM64 || COMPILE_TEST
> >> diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
> >> index 75d035150118..97c8cefc2fd0 100644
> >> --- a/drivers/clk/qcom/Makefile
> >> +++ b/drivers/clk/qcom/Makefile
> >> @@ -101,6 +101,7 @@ obj-$(CONFIG_SDX_GCC_75) += gcc-sdx75.o
> >>   obj-$(CONFIG_SM_CAMCC_6350) += camcc-sm6350.o
> >>   obj-$(CONFIG_SM_CAMCC_8250) += camcc-sm8250.o
> >>   obj-$(CONFIG_SM_CAMCC_8450) += camcc-sm8450.o
> >> +obj-$(CONFIG_SM_CAMCC_8550) += camcc-sm8550.o
> >>   obj-$(CONFIG_SM_DISPCC_6115) += dispcc-sm6115.o
> >>   obj-$(CONFIG_SM_DISPCC_6125) += dispcc-sm6125.o
> >>   obj-$(CONFIG_SM_DISPCC_6350) += dispcc-sm6350.o
> >> diff --git a/drivers/clk/qcom/camcc-sm8550.c b/drivers/clk/qcom/camcc-sm8550.c
> >> new file mode 100644
> >> index 000000000000..85f0c1e09b2b
> >> --- /dev/null
> >> +++ b/drivers/clk/qcom/camcc-sm8550.c
> >> @@ -0,0 +1,3405 @@
> >> +// SPDX-License-Identifier: GPL-2.0-only
> >> +/*
> >> + * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
> >> + */
> >> +
> >> +#include <linux/clk-provider.h>
> >> +#include <linux/module.h>
> >> +#include <linux/of_device.h>
> >> +#include <linux/pm_runtime.h>
> >> +#include <linux/regmap.h>
> >> +
> >> +#include <dt-bindings/clock/qcom,sm8550-camcc.h>
> >> +
> >> +#include "clk-alpha-pll.h"
> >> +#include "clk-branch.h"
> >> +#include "clk-rcg.h"
> >> +#include "clk-regmap.h"
> >> +#include "common.h"
> >> +#include "gdsc.h"
> >> +#include "reset.h"
> >> +
> >> +enum {
> >> +       DT_IFACE,
> >> +       DT_BI_TCXO,
> >> +};
> >> +
> >> +enum {
> >> +       P_BI_TCXO,
> >> +       P_CAM_CC_PLL0_OUT_EVEN,
> >> +       P_CAM_CC_PLL0_OUT_MAIN,
> >> +       P_CAM_CC_PLL0_OUT_ODD,
> >> +       P_CAM_CC_PLL1_OUT_EVEN,
> >> +       P_CAM_CC_PLL2_OUT_EVEN,
> >> +       P_CAM_CC_PLL2_OUT_MAIN,
> >> +       P_CAM_CC_PLL3_OUT_EVEN,
> >> +       P_CAM_CC_PLL4_OUT_EVEN,
> >> +       P_CAM_CC_PLL5_OUT_EVEN,
> >> +       P_CAM_CC_PLL6_OUT_EVEN,
> >> +       P_CAM_CC_PLL7_OUT_EVEN,
> >> +       P_CAM_CC_PLL8_OUT_EVEN,
> >> +       P_CAM_CC_PLL9_OUT_EVEN,
> >> +       P_CAM_CC_PLL9_OUT_ODD,
> >> +       P_CAM_CC_PLL10_OUT_EVEN,
> >> +       P_CAM_CC_PLL11_OUT_EVEN,
> >> +       P_CAM_CC_PLL12_OUT_EVEN,
> >> +};
> >> +
> >> +static const struct pll_vco lucid_ole_vco[] = {
> >> +       { 249600000, 2300000000, 0 },
> >> +};
> >> +
> >> +static const struct pll_vco rivian_ole_vco[] = {
> >> +       { 777000000, 1285000000, 0 },
> >> +};
> >> +
> >> +static const struct alpha_pll_config cam_cc_pll0_config = {
> >> +       /* .l includes RINGOSC_CAL_L_VAL, CAL_L_VAL, L_VAL fields */
> >> +       .l = 0x4444003e,
> >
> > I'd still insist on not touching the config.l field semantics.
> >
>
> We feel it is better to update config->l field and reuse existing code
> than adding separate function for lucid ole pll configure.

As you probably got it, I'm not convinced that it is a better
approach. You are feeding additional data in a single configuration
field and passing constant data as variadic one.

>
> >> +       .alpha = 0x8000,
> >> +       .config_ctl_val = 0x20485699,
> >> +       .config_ctl_hi_val = 0x00182261,
> >> +       .config_ctl_hi1_val = 0x82aa299c,
> >> +       .test_ctl_val = 0x00000000,
> >> +       .test_ctl_hi_val = 0x00000003,
> >> +       .test_ctl_hi1_val = 0x00009000,
> >> +       .test_ctl_hi2_val = 0x00000034,
> >> +       .user_ctl_val = 0x00008400,
> >> +       .user_ctl_hi_val = 0x00000005,
> >> +};
> >> +
> >
> > [skipped the rest, LGTM]
> >
> >> +
> >> +static struct platform_driver cam_cc_sm8550_driver = {
> >> +       .probe = cam_cc_sm8550_probe,
> >> +       .driver = {
> >> +               .name = "cam_cc-sm8550",
> >> +               .of_match_table = cam_cc_sm8550_match_table,
> >> +       },
> >> +};
> >> +
> >> +static int __init cam_cc_sm8550_init(void)
> >> +{
> >> +       return platform_driver_register(&cam_cc_sm8550_driver);
> >> +}
> >> +subsys_initcall(cam_cc_sm8550_init);
> >
> > As it was pointed out, this driver is built as a module by default.
> > Please perform the tesing and cleanup before sending the driver and
> > use module_platform_driver.
> >
>
> We want clock drivers to be probed early in the bootup to avoid any
> probe deferrals of consumer drivers. If there is any scenario where
> clock drivers are built statically into kernel, then subsys_initcall()
> will ensure clock drivers are probed earlier. When built as module,
> subsys_initcall() will fallback to module_init() which is same as
> module_platform_driver().

Consumer driver probe deferrals are nowadays significantly prevented
by using devlink rather than depending on the initialisation level.
And I think both GKI and defconfig build camcc as modules.

>
> Thanks,
> Jagadeesh
>
> >> +
> >> +static void __exit cam_cc_sm8550_exit(void)
> >> +{
> >> +       platform_driver_unregister(&cam_cc_sm8550_driver);
> >> +}
> >> +module_exit(cam_cc_sm8550_exit);
> >> +
> >> +MODULE_DESCRIPTION("QTI CAMCC SM8550 Driver");
> >> +MODULE_LICENSE("GPL");
> >> --
> >> 2.40.1
> >>
> >
> >


-- 
With best wishes
Dmitry