Re: [PATCH 4/6] clk: stm32f4: Add I2S clock

From: Gabriel Fernandez
Date: Tue Nov 08 2016 - 11:27:49 EST




On 11/07/2016 03:14 PM, Daniel Thompson wrote:
On 07/11/16 13:05, gabriel.fernandez@xxxxxx wrote:
From: Gabriel Fernandez <gabriel.fernandez@xxxxxx>

This patch introduces I2S clock for stm32f4 soc.
The I2S clock could be derived from an external clock or from pll-i2s

Signed-off-by: Gabriel Fernandez <gabriel.fernandez@xxxxxx>
---
drivers/clk/clk-stm32f4.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c
index 5fa5d51..b7cb359 100644
--- a/drivers/clk/clk-stm32f4.c
+++ b/drivers/clk/clk-stm32f4.c
@@ -216,6 +216,7 @@ enum {
SYSTICK, FCLK, CLK_LSI, CLK_LSE, CLK_HSE_RTC, CLK_RTC,
PLL_VCO_I2S, PLL_VCO_SAI,
CLK_LCD,
+ CLK_I2S,

Sorry, this has just clicked and it applies to most of the other patches, but adding things to this list effectively extends the clock bindings (i.e. the list of valid "other" clocks access with a primary index of 1).

This list if a list of "arbitrary" constants by which DT periphericals can be linked to specific clocks.

So...

1) If a clock is introduced here we should update the clock binding
documentations.

2) If no peripheral can connect to the clock (because it is internal
to the clock gen logic and peripherals must connect to the gated
version) it should not be included in this enum.

3) I failed to mention this when the four undocumented clocks
(LSI, LSE, HSE_RTC and RTC) were added.

4) I *should* have added a comment explaining the above to the code.


ok i agree

END_PRIMARY_CLK
};

@@ -967,6 +968,8 @@ static struct clk_hw *stm32_register_cclk(struct device *dev, const char *name,

static const char *sdmux_parents[2] = { "pll48", "sys" };

+static const char *i2s_parents[2] = { "plli2s-r", NULL };
+
struct stm32f4_clk_data {
const struct stm32f4_gate_data *gates_data;
const u64 *gates_map;
@@ -1005,7 +1008,7 @@ struct stm32f4_clk_data {

static void __init stm32f4_rcc_init(struct device_node *np)
{
- const char *hse_clk;
+ const char *hse_clk, *i2s_in_clk;
int n;
const struct of_device_id *match;
const struct stm32f4_clk_data *data;
@@ -1038,6 +1041,7 @@ static void __init stm32f4_rcc_init(struct device_node *np)
stm32f4_gate_map = data->gates_map;

hse_clk = of_clk_get_parent_name(np, 0);
+ i2s_in_clk = of_clk_get_parent_name(np, 1);

Again this looks like a change to the DT bindings.

ok

Also does the code work if i2s_in_clk is NULL or as you hoping to get away with a not-backwards compatible change?


yes it works if i2s_in_clk is NULL.

BR
Gabriel

Daniel.



clk_register_fixed_rate_with_accuracy(NULL, "hsi", NULL, 0,
16000000, 160000);
@@ -1053,6 +1057,12 @@ static void __init stm32f4_rcc_init(struct device_node *np)
clks[PLL_VCO_SAI] = stm32f4_rcc_register_pll(pllsrc,
&data->pll_data[2], &stm32f4_clk_lock);

+ i2s_parents[1] = i2s_in_clk;
+
+ clks[CLK_I2S] = clk_hw_register_mux_table(NULL, "i2s",
+ i2s_parents, ARRAY_SIZE(i2s_parents), 0,
+ base + STM32F4_RCC_CFGR, 23, 1, 0, NULL,
+ &stm32f4_clk_lock);
sys_parents[1] = hse_clk;
clk_register_mux_table(
NULL, "sys", sys_parents, ARRAY_SIZE(sys_parents), 0,