linux-kernel - [PATCH v2 1/1] i2c: qcom-geni: Support systems with 32MHz serial engine clock

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Message-ID: <20240926034304.3565278-1-quic_mmanikan@quicinc.com>
Date: Thu, 26 Sep 2024 09:13:04 +0530
From: Manikanta Mylavarapu <quic_mmanikan@...cinc.com>
To: <andi.shyti@...nel.org>, <quic_mmanikan@...cinc.com>,
        <linux-arm-msm@...r.kernel.org>, <linux-i2c@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC: <quic_srichara@...cinc.com>, <quic_varada@...cinc.com>
Subject: [PATCH v2 1/1] i2c: qcom-geni: Support systems with 32MHz serial engine clock

In existing socs, I2C serial engine is sourced from XO (19.2MHz).
Where as in IPQ5424, I2C serial engine is sourced from GPLL0 (32MHz).

The existing map table is based on 19.2MHz. This patch incorporate
the clock map table to derive the SCL clock from the 32MHz source
clock frequency.

Signed-off-by: Manikanta Mylavarapu <quic_mmanikan@...cinc.com>
---
Changes in v2:
	- Dropped IPQ5424 from the commit title
	- Added else part to assign geni_i2c_clk_map_19p2mhz to itr
	- Dropped MHZ macro and used HZ_PER_MHZ macro
	- Expanded SE to serial engine
	- Added the reason for 32MHz clock in commit message

 drivers/i2c/busses/i2c-qcom-geni.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index 212336f724a6..22f2a0d83641 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -16,6 +16,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/soc/qcom/geni-se.h>
 #include <linux/spinlock.h>
+#include <linux/units.h>
 
 #define SE_I2C_TX_TRANS_LEN		0x26c
 #define SE_I2C_RX_TRANS_LEN		0x270
@@ -146,18 +147,30 @@ struct geni_i2c_clk_fld {
  * clk_freq_out = t / t_cycle
  * source_clock = 19.2 MHz
  */
-static const struct geni_i2c_clk_fld geni_i2c_clk_map[] = {
+static const struct geni_i2c_clk_fld geni_i2c_clk_map_19p2mhz[] = {
 	{KHZ(100), 7, 10, 11, 26},
 	{KHZ(400), 2,  5, 12, 24},
 	{KHZ(1000), 1, 3,  9, 18},
 };
 
+/* source_clock = 32 MHz */
+static const struct geni_i2c_clk_fld geni_i2c_clk_map_32mhz[] = {
+	{KHZ(100), 7, 14, 18, 40},
+	{KHZ(400), 4,  3, 11, 20},
+	{KHZ(1000), 4, 3,  6, 15},
+};
+
 static int geni_i2c_clk_map_idx(struct geni_i2c_dev *gi2c)
 {
 	int i;
-	const struct geni_i2c_clk_fld *itr = geni_i2c_clk_map;
+	const struct geni_i2c_clk_fld *itr;
+
+	if (clk_get_rate(gi2c->se.clk) == 32 * HZ_PER_MHZ)
+		itr = geni_i2c_clk_map_32mhz;
+	else
+		itr = geni_i2c_clk_map_19p2mhz;
 
-	for (i = 0; i < ARRAY_SIZE(geni_i2c_clk_map); i++, itr++) {
+	for (i = 0; i < ARRAY_SIZE(geni_i2c_clk_map_19p2mhz); i++, itr++) {
 		if (itr->clk_freq_out == gi2c->clk_freq_out) {
 			gi2c->clk_fld = itr;
 			return 0;
-- 
2.34.1