Re: [PATCH 2/2] clk: qcom: Add display clock controller driver for SDM845

From: Stephen Boyd
Date: Tue Jun 12 2018 - 03:55:47 EST


Quoting Taniya Das (2018-06-04 00:56:25)
> diff --git a/drivers/clk/qcom/dispcc-sdm845.c b/drivers/clk/qcom/dispcc-sdm845.c
> new file mode 100644
> index 0000000..317ab33
> --- /dev/null
> +++ b/drivers/clk/qcom/dispcc-sdm845.c
> @@ -0,0 +1,679 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018, The Linux Foundation. All rights reserved.
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/reset-controller.h>
> +
> +#include <dt-bindings/clock/qcom,dispcc-sdm845.h>
> +
> +#include "clk-alpha-pll.h"
> +#include "clk-branch.h"
> +#include "clk-pll.h"
> +#include "clk-rcg.h"
> +#include "clk-regmap.h"
> +#include "clk-regmap-divider.h"

Used?

> +#include "common.h"
> +#include "gdsc.h"
> +#include "reset.h"
> +
> +#define F(f, s, h, m, n) { (f), (s), (2 * (h) - 1), (m), (n) }

We really need to move this into the header file.

$ git grep '#define F(' -- drivers/clk/qcom/ | wc -l
13

> +
[...]
> +static const char * const disp_cc_parent_names_4[] = {
> + "bi_tcxo",
> + "dsi0_phy_pll_out_dsiclk",
> + "dsi1_phy_pll_out_dsiclk",
> + "core_bi_pll_test_se",
> +};
> +
> +static const struct alpha_pll_config disp_cc_pll0_config = {
> + .l = 0x2c,
> + .alpha = 0xcaaa,
> +};

Any reason this can't be put on the stack in the probe function?

> +
> +static struct clk_alpha_pll disp_cc_pll0 = {
> + .offset = 0x0,
> + .regs = clk_alpha_pll_regs[CLK_ALPHA_PLL_TYPE_FABIA],
> + .clkr = {
> + .hw.init = &(struct clk_init_data){
> + .name = "disp_cc_pll0",
> + .parent_names = (const char *[]){ "bi_tcxo" },
> + .num_parents = 1,
> + .ops = &clk_alpha_pll_fabia_ops,
> + },
> + },
> +};
[...]
> +
> +static struct clk_rcg2 disp_cc_mdss_pclk0_clk_src = {
> + .cmd_rcgr = 0x2058,
> + .mnd_width = 8,
> + .hid_width = 5,
> + .parent_map = disp_cc_parent_map_4,
> + .clkr.hw.init = &(struct clk_init_data){
> + .name = "disp_cc_mdss_pclk0_clk_src",
> + .parent_names = disp_cc_parent_names_4,
> + .num_parents = 4,
> + .flags = CLK_SET_RATE_PARENT | CLK_GET_RATE_NOCACHE,

Why is the nocache flag needed? Applies to all clks in this file.

> + .ops = &clk_pixel_ops,
> + },
> +};
> +
> +static struct clk_rcg2 disp_cc_mdss_pclk1_clk_src = {
> + .cmd_rcgr = 0x2070,
> + .mnd_width = 8,
> + .hid_width = 5,
> + .parent_map = disp_cc_parent_map_4,
> + .clkr.hw.init = &(struct clk_init_data){
[...]
> +
> +static const struct regmap_config disp_cc_sdm845_regmap_config = {
> + .reg_bits = 32,
> + .reg_stride = 4,
> + .val_bits = 32,
> + .max_register = 0x10000,

This seems arbitrarily large. List the actual end?

> + .fast_io = true,
> +};
> +
> +static const struct qcom_cc_desc disp_cc_sdm845_desc = {
> + .config = &disp_cc_sdm845_regmap_config,
> + .clks = disp_cc_sdm845_clocks,
> + .num_clks = ARRAY_SIZE(disp_cc_sdm845_clocks),
> + .resets = disp_cc_sdm845_resets,
> + .num_resets = ARRAY_SIZE(disp_cc_sdm845_resets),
> + .gdscs = disp_cc_sdm845_gdscs,
> + .num_gdscs = ARRAY_SIZE(disp_cc_sdm845_gdscs),
> +};
> +
> +static const struct of_device_id disp_cc_sdm845_match_table[] = {
> + { .compatible = "qcom,sdm845-dispcc" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, disp_cc_sdm845_match_table);
> +
> +static int disp_cc_sdm845_probe(struct platform_device *pdev)
> +{
> + struct regmap *regmap;
> +
> + regmap = qcom_cc_map(pdev, &disp_cc_sdm845_desc);
> + if (IS_ERR(regmap))
> + return PTR_ERR(regmap);
> +
> + clk_fabia_pll_configure(&disp_cc_pll0, regmap, &disp_cc_pll0_config);
> +
> + /* Enable clock gating for DSI and MDP clocks */

Hardware clock gating? What does this mean.

> + regmap_update_bits(regmap, 0x8000, 0x7f0, 0x7f0);
> +
> + return qcom_cc_really_probe(pdev, &disp_cc_sdm845_desc, regmap);
> +}