diff options
author | Dmitry Baryshkov <dmitry.baryshkov@linaro.org> | 2023-01-27 02:03:19 +0300 |
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committer | Bjorn Andersson <andersson@kernel.org> | 2023-02-09 01:31:52 +0300 |
commit | 027726365906fc863265635e545d063a45807fe8 (patch) | |
tree | 6bcc94ab7a3374a2a14a2c786f4e80aa6ff6422a /drivers/clk/qcom/apcs-msm8996.c | |
parent | d4cb3e7113f82f7378527890aa7b4006234665fe (diff) | |
download | linux-027726365906fc863265635e545d063a45807fe8.tar.xz |
clk: qcom: add the driver for the MSM8996 APCS clocks
Add a simple driver handling the APCS clocks on MSM8996. For now it
supports just a single aux clock, linking GPLL0 to CPU and CBF clocks.
Note, there is little sense in registering sys_apcs_aux as a child of
gpll0. The PLL is always-on. And listing the gpll0 as a property of the
apcs would delay its probing until the GCC has been probed (while we
would like for the apcs to be probed as early as possible).
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
[bjorn: Fixed spelling of register, per Stephen's feedback]
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230126230319.3977109-8-dmitry.baryshkov@linaro.org
Diffstat (limited to 'drivers/clk/qcom/apcs-msm8996.c')
-rw-r--r-- | drivers/clk/qcom/apcs-msm8996.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/drivers/clk/qcom/apcs-msm8996.c b/drivers/clk/qcom/apcs-msm8996.c new file mode 100644 index 000000000000..7ec4022c5b43 --- /dev/null +++ b/drivers/clk/qcom/apcs-msm8996.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Qualcomm APCS clock controller driver + * + * Copyright (c) 2022, Linaro Limited + * Author: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> + */ + +#include <linux/bits.h> +#include <linux/clk-provider.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> + +#define APCS_AUX_OFFSET 0x50 + +#define APCS_AUX_DIV_MASK GENMASK(17, 16) +#define APCS_AUX_DIV_2 0x1 + +static int qcom_apcs_msm8996_clk_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device *parent = dev->parent; + struct regmap *regmap; + struct clk_hw *hw; + unsigned int val; + int ret = -ENODEV; + + regmap = dev_get_regmap(parent, NULL); + if (!regmap) { + dev_err(dev, "failed to get regmap: %d\n", ret); + return ret; + } + + regmap_read(regmap, APCS_AUX_OFFSET, &val); + regmap_update_bits(regmap, APCS_AUX_OFFSET, APCS_AUX_DIV_MASK, + FIELD_PREP(APCS_AUX_DIV_MASK, APCS_AUX_DIV_2)); + + /* + * This clock is used during CPU cluster setup while setting up CPU PLLs. + * Add hardware mandated delay to make sure that the sys_apcs_aux clock + * is stable (after setting the divider) before continuing + * bootstrapping to keep CPUs from ending up in a weird state. + */ + udelay(5); + + /* + * As this clocks is a parent of the CPU cluster clocks and is actually + * used as a parent during CPU clocks setup, we want for it to register + * as early as possible, without letting fw_devlink to delay probing of + * either of the drivers. + * + * The sys_apcs_aux is a child (divider) of gpll0, but we register it + * as a fixed rate clock instead to ease bootstrapping procedure. By + * doing this we make sure that CPU cluster clocks are able to be setup + * early during the boot process (as it is recommended by Qualcomm). + */ + hw = devm_clk_hw_register_fixed_rate(dev, "sys_apcs_aux", NULL, 0, 300000000); + if (IS_ERR(hw)) + return PTR_ERR(hw); + + return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, hw); +} + +static struct platform_driver qcom_apcs_msm8996_clk_driver = { + .probe = qcom_apcs_msm8996_clk_probe, + .driver = { + .name = "qcom-apcs-msm8996-clk", + }, +}; + +/* Register early enough to fix the clock to be used for other cores */ +static int __init qcom_apcs_msm8996_clk_init(void) +{ + return platform_driver_register(&qcom_apcs_msm8996_clk_driver); +} +postcore_initcall(qcom_apcs_msm8996_clk_init); + +static void __exit qcom_apcs_msm8996_clk_exit(void) +{ + platform_driver_unregister(&qcom_apcs_msm8996_clk_driver); +} +module_exit(qcom_apcs_msm8996_clk_exit); + +MODULE_AUTHOR("Dmitry Baryshkov <dmitry.baryshkov@linaro.org>"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Qualcomm MSM8996 APCS clock driver"); |