Re: [PATCH v5 4/4] drm/mediatek: config mipitx impedance with calibration data

[Chun-Kuang Hu <chunkuang.hu@kernel.org>]

Hi, Jitao:

Jitao Shi <jitao.shi@mediatek.com> 於 2020年4月10日 週五 下午12:33寫道：
>
> Read calibration data from nvmem, and config mipitx impedance with
> calibration data to make sure their impedance are 100ohm.
>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_mipi_tx.c        | 40 +++++++++++++++++++
>  drivers/gpu/drm/mediatek/mtk_mipi_tx.h        |  3 ++
>  drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c | 21 ++++++++++
>  3 files changed, 64 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_mipi_tx.c b/drivers/gpu/drm/mediatek/mtk_mipi_tx.c
> index e301af64809e..5e91fc2c1318 100644
> --- a/drivers/gpu/drm/mediatek/mtk_mipi_tx.c
> +++ b/drivers/gpu/drm/mediatek/mtk_mipi_tx.c
> @@ -88,6 +88,44 @@ static const struct phy_ops mtk_mipi_tx_ops = {
>         .owner = THIS_MODULE,
>  };
>
> +static void mtk_mipi_tx_get_calibration_datal(struct mtk_mipi_tx *mipi_tx)
> +{
> +       struct nvmem_cell *cell;
> +       size_t len;
> +       u32 *buf;
> +
> +       memset(mipi_tx->rt_code, 0, sizeof(mipi_tx->rt_code));

You use kzalloc() to allocate mipi_tx, so this is already zero-initialized.

> +       cell = nvmem_cell_get(mipi_tx->dev, "calibration-data");
> +       if (IS_ERR(cell)) {
> +               dev_info(mipi_tx->dev, "can't get nvmem_cell_get, ignore it\n");
> +       } else {

If you return when error, you could get rid of the 'else', so you
could reduce many 'tab' and reduce the probability of one line over 80
character.

> +               buf = (u32 *)nvmem_cell_read(cell, &len);
> +               nvmem_cell_put(cell);
> +
> +               if (IS_ERR(buf)) {
> +                       dev_info(mipi_tx->dev, "can't get data, ignore it\n");
> +               } else {

Ditto.

Regards,
Chun-Kuang.

> +                       if (len < 3 * sizeof(u32)) {
> +                               dev_info(mipi_tx->dev, "invalid calibration data\n");
> +                               kfree(buf);
> +                               return;
> +                       }
> +
> +                       mipi_tx->rt_code[0] = ((buf[0] >> 6 & 0x1f) << 5) |
> +                                              (buf[0] >> 11 & 0x1f);
> +                       mipi_tx->rt_code[1] = ((buf[1] >> 27 & 0x1f) << 5) |
> +                                              (buf[0] >> 1 & 0x1f);
> +                       mipi_tx->rt_code[2] = ((buf[1] >> 17 & 0x1f) << 5) |
> +                                              (buf[1] >> 22 & 0x1f);
> +                       mipi_tx->rt_code[3] = ((buf[1] >> 7 & 0x1f) << 5) |
> +                                              (buf[1] >> 12 & 0x1f);
> +                       mipi_tx->rt_code[4] = ((buf[2] >> 27 & 0x1f) << 5) |
> +                                              (buf[1] >> 2 & 0x1f);
> +                       kfree(buf);
> +               }
> +       }
> +}
> +
>  static int mtk_mipi_tx_probe(struct platform_device *pdev)
>  {
>         struct device *dev = &pdev->dev;
> @@ -174,6 +212,8 @@ static int mtk_mipi_tx_probe(struct platform_device *pdev)
>
>         mipi_tx->dev = dev;
>
> +       mtk_mipi_tx_get_calibration_datal(mipi_tx);
> +
>         return of_clk_add_provider(dev->of_node, of_clk_src_simple_get,
>                                    mipi_tx->pll);
>  }
> diff --git a/drivers/gpu/drm/mediatek/mtk_mipi_tx.h b/drivers/gpu/drm/mediatek/mtk_mipi_tx.h
> index eea44327fe9f..c76f07c3fdeb 100644
> --- a/drivers/gpu/drm/mediatek/mtk_mipi_tx.h
> +++ b/drivers/gpu/drm/mediatek/mtk_mipi_tx.h
> @@ -12,9 +12,11 @@
>  #include <linux/delay.h>
>  #include <linux/io.h>
>  #include <linux/module.h>
> +#include <linux/nvmem-consumer.h>
>  #include <linux/of_device.h>
>  #include <linux/platform_device.h>
>  #include <linux/phy/phy.h>
> +#include <linux/slab.h>
>
>  struct mtk_mipitx_data {
>         const u32 mppll_preserve;
> @@ -28,6 +30,7 @@ struct mtk_mipi_tx {
>         void __iomem *regs;
>         u32 data_rate;
>         u32 mipitx_drive;
> +       u32 rt_code[5];
>         const struct mtk_mipitx_data *driver_data;
>         struct clk_hw pll_hw;
>         struct clk *pll;
> diff --git a/drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c b/drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c
> index e4cc967750cb..9f3e55aeebb2 100644
> --- a/drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c
> +++ b/drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c
> @@ -28,6 +28,7 @@
>  #define MIPITX_PLL_CON4                0x003c
>  #define RG_DSI_PLL_IBIAS               (3 << 10)
>
> +#define MIPITX_D2P_RTCODE      0x0100
>  #define MIPITX_D2_SW_CTL_EN    0x0144
>  #define MIPITX_D0_SW_CTL_EN    0x0244
>  #define MIPITX_CK_CKMODE_EN    0x0328
> @@ -108,6 +109,24 @@ static const struct clk_ops mtk_mipi_tx_pll_ops = {
>         .recalc_rate = mtk_mipi_tx_pll_recalc_rate,
>  };
>
> +static void mtk_mipi_tx_config_calibration_data(struct mtk_mipi_tx *mipi_tx)
> +{
> +       int i, j;
> +
> +       for (i = 0; i < 5; i++) {
> +               if ((mipi_tx->rt_code[i] & 0x1f) == 0)
> +                       mipi_tx->rt_code[i] |= 0x10;
> +
> +               if ((mipi_tx->rt_code[i] >> 5 & 0x1f) == 0)
> +                       mipi_tx->rt_code[i] |= 0x10 << 5;
> +
> +               for (j = 0; j < 10; j++)
> +                       mtk_mipi_tx_update_bits(mipi_tx,
> +                               MIPITX_D2P_RTCODE * (i + 1) + j * 4,
> +                               1, mipi_tx->rt_code[i] >> j & 1);
> +       }
> +}
> +
>  static void mtk_mipi_tx_power_on_signal(struct phy *phy)
>  {
>         struct mtk_mipi_tx *mipi_tx = phy_get_drvdata(phy);
> @@ -130,6 +149,8 @@ static void mtk_mipi_tx_power_on_signal(struct phy *phy)
>                                 RG_DSI_HSTX_LDO_REF_SEL,
>                                 (mipi_tx->mipitx_drive - 3000) / 200 << 6);
>
> +       mtk_mipi_tx_config_calibration_data(mipi_tx);
> +
>         mtk_mipi_tx_set_bits(mipi_tx, MIPITX_CK_CKMODE_EN, DSI_CK_CKMODE_EN);
>  }
>
> --
> 2.21.0
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