ASoC: ti: davinci-mcasp: Streamline pdir behavior across rx & tx streams

Simplify the mcasp_set_clk_pdir caller convention in start/stop stream
function, to make it so that set_clk_pdir gets called regardless when
stream starts and also disables when stream ends.

Functionality-wise, everything remains the same as the previously skipped
calls are now either correctly configured
(when McASP is SND_SOC_DAIFMT_BP_FC - pdir needs to be enabled)
or called with a bitmask of zero (when McASP is SND_SOC_DAIFMT_BC_FC - pdir
gets disabled).

On brief regarding McASP Clock and Frame sync configurations, refer to [0].

[0]:TRM Section 12.1.1.4.2 https://www.ti.com/lit/ug/sprujd4a/sprujd4a.pdf

Signed-off-by: Sen Wang <sen@ti.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Tested-by: Paresh Bhagat <p-bhagat@ti.com>
Link: https://patch.msgid.link/20260203003703.2334443-4-sen@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: SenWang125

sound/soc/ti/davinci-mcasp.c

@@ -236,8 +236,8 @@ static void mcasp_start_rx(struct davinci_mcasp *mcasp)
 	if (mcasp_is_frame_producer(mcasp) && mcasp_is_synchronous(mcasp)) {
 		mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXHCLKRST);
 		mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXCLKRST);
-		mcasp_set_clk_pdir(mcasp, true);
 	}
+	mcasp_set_clk_pdir(mcasp, true);
 
 	/* Activate serializer(s) */
 	mcasp_set_reg(mcasp, DAVINCI_MCASP_RXSTAT_REG, 0xFFFFFFFF);
@@ -312,10 +312,10 @@ static void mcasp_stop_rx(struct davinci_mcasp *mcasp)
 	 * In synchronous mode stop the TX clocks if no other stream is
 	 * running
 	 */
-	if (mcasp_is_frame_producer(mcasp) && mcasp_is_synchronous(mcasp) && !mcasp->streams) {
+	if (!mcasp->streams)
 		mcasp_set_clk_pdir(mcasp, false);
+	if (mcasp_is_frame_producer(mcasp) && mcasp_is_synchronous(mcasp) && !mcasp->streams)
 		mcasp_set_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, 0);
-	}
 
 	mcasp_set_reg(mcasp, DAVINCI_MCASP_GBLCTLR_REG, 0);
 	mcasp_set_reg(mcasp, DAVINCI_MCASP_RXSTAT_REG, 0xFFFFFFFF);
@@ -341,7 +341,7 @@ static void mcasp_stop_tx(struct davinci_mcasp *mcasp)
 	 */
 	if (mcasp_is_frame_producer(mcasp) && mcasp_is_synchronous(mcasp) && mcasp->streams)
 		val =  TXHCLKRST | TXCLKRST | TXFSRST;
-	else
+	if (!mcasp->streams)
 		mcasp_set_clk_pdir(mcasp, false);