Re: [PATCH v7 06/34] i2c: tegra: Remove i2c_dev.clk_divisor_non_hs_mode member

Thierry Reding
2020-09-17T11:26:46Z

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On Wed, Sep 09, 2020 at 01:39:38AM +0300, Dmitry Osipenko wrote:
> The "non_hs_mode" divisor value is fixed, thus there is no need to have
> the variable i2c_dev.clk_divisor_non_hs_mode struct member. Let's remove
> it and move the mode selection into tegra_i2c_init() where it can be
> united with the timing selection.
>
> Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/i2c/busses/i2c-tegra.c | 46 ++++++++++++++++------------------
> 1 file changed, 21 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 720a75439e91..85ed0e02d48c 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -250,7 +250,6 @@ struct tegra_i2c_hw_feature {
> * @msg_buf_remaining: size of unsent data in the message buffer
> * @msg_read: identifies read transfers
> * @bus_clk_rate: current I2C bus clock rate
> - * @clk_divisor_non_hs_mode: clock divider for non-high-speed modes
> * @is_multimaster_mode: track if I2C controller is in multi-master mode
> * @tx_dma_chan: DMA transmit channel
> * @rx_dma_chan: DMA receive channel
> @@ -281,7 +280,6 @@ struct tegra_i2c_dev {
> size_t msg_buf_remaining;
> int msg_read;
> u32 bus_clk_rate;
> - u16 clk_divisor_non_hs_mode;
> bool is_multimaster_mode;
> struct dma_chan *tx_dma_chan;
> struct dma_chan *rx_dma_chan;
> @@ -783,6 +781,7 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
> u32 val;
> int err;
> u32 clk_divisor, clk_multiplier;
> + u32 non_hs_mode;
> u32 tsu_thd;
> u8 tlow, thigh;
>
> @@ -805,24 +804,33 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
> if (i2c_dev->is_vi)
> tegra_i2c_vi_init(i2c_dev);
>
> - /* Make sure clock divisor programmed correctly */
> - clk_divisor = FIELD_PREP(I2C_CLK_DIVISOR_HSMODE,
> - i2c_dev->hw->clk_divisor_hs_mode) |
> - FIELD_PREP(I2C_CLK_DIVISOR_STD_FAST_MODE,
> - i2c_dev->clk_divisor_non_hs_mode);
> - i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR);
> -
> - if (i2c_dev->bus_clk_rate > I2C_MAX_STANDARD_MODE_FREQ &&
> - i2c_dev->bus_clk_rate <= I2C_MAX_FAST_MODE_PLUS_FREQ) {
> + switch (i2c_dev->bus_clk_rate) {
> + case I2C_MAX_STANDARD_MODE_FREQ + 1 ... I2C_MAX_FAST_MODE_PLUS_FREQ:

Is there are particular reason for switching the simple conditional to a
switch here? The old variant looks much easier to understand to me.

Thierry

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