[PATCH 5/7] nvmem: imx-ocotp: Add i.MX7D timing write clock setup support

[Bryan O'Donoghue]

This patch adds logic to correctly setup the write timing parameters
when blowing an OTP fuse for the i.MX7S/D.

Fixes: 0642bac7da42 ("nvmem: imx-ocotp: add write support")

Signed-off-by: Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
---
 drivers/nvmem/imx-ocotp.c | 61 ++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 55 insertions(+), 6 deletions(-)

diff --git a/drivers/nvmem/imx-ocotp.c b/drivers/nvmem/imx-ocotp.c
index 0cd7e03..40a1669 100644
--- a/drivers/nvmem/imx-ocotp.c
+++ b/drivers/nvmem/imx-ocotp.c
@@ -51,6 +51,7 @@
 #define IMX_OCOTP_BM_CTRL_REL_SHADOWS	0x00000400
 
 #define DEF_RELAX			20 /* > 16.5ns */
+#define DEF_FSOURCE			1001
 #define IMX_OCOTP_WR_UNLOCK		0x3E770000
 #define IMX_OCOTP_READ_LOCKED_VAL	0xBADABADA
 
@@ -60,6 +61,7 @@ struct octp_params {
 	unsigned int nregs;
 	bool banked;
 	unsigned int regs_per_bank;
+	bool mx7_timing;
 };
 
 struct ocotp_priv {
@@ -194,6 +196,25 @@ static void imx_ocotp_set_imx6_timing(struct ocotp_priv *priv)
 	writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);
 }
 
+static void imx_ocotp_set_imx7_timing(struct ocotp_priv *priv)
+{
+	unsigned long clk_rate = 0;
+	unsigned long fsource, strobe_prog;
+	u32 timing = 0;
+
+	/* i.MX 7Solo Applications Processor Reference Manual, Rev. 0.1
+	 * 6.4.3.3
+	 */
+	clk_rate = clk_get_rate(priv->clk);
+	fsource = DIV_ROUND_UP(((clk_rate / 1000) * DEF_FSOURCE), 1000000) + 1;
+	strobe_prog = ((clk_rate * 10) / 1000000) + 1;
+
+	timing = strobe_prog & 0x00000FFF;
+	timing |= (fsource       << 12) & 0x000FF000;
+
+	writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);
+}
+
 static int imx_ocotp_write(void *context, unsigned int offset, void *val,
 			   size_t bytes)
 {
@@ -220,7 +241,10 @@ static int imx_ocotp_write(void *context, unsigned int offset, void *val,
 	}
 
 	/* Setup the write timing values */
-	imx_ocotp_set_imx6_timing(priv);
+	if (priv->params->mx7_timing)
+		imx_ocotp_set_imx7_timing(priv);
+	else
+		imx_ocotp_set_imx6_timing(priv);
 
 	/* 47.3.1.3.2
 	 * Check that HW_OCOTP_CTRL[BUSY] and HW_OCOTP_CTRL[ERROR] are clear.
@@ -373,11 +397,36 @@ static struct nvmem_config imx_ocotp_nvmem_config = {
 };
 
 static const struct octp_params params[] = {
-	{ .nregs = 128, .banked = false, .regs_per_bank = 0},
-	{ .nregs = 64,  .banked = false, .regs_per_bank = 0},
-	{ .nregs = 128, .banked = false, .regs_per_bank = 0},
-	{ .nregs = 128, .banked = false, .regs_per_bank = 0},
-	{ .nregs = 64,  .banked = true, .regs_per_bank = 4},
+	{
+		.nregs = 128,
+		.banked = false,
+		.regs_per_bank = 0,
+		.mx7_timing = false
+	},
+	{
+		.nregs = 64,
+		.banked = false,
+		.regs_per_bank = 0,
+		.mx7_timing = false
+	},
+	{
+		.nregs = 128,
+		.banked = false,
+		.regs_per_bank = 0,
+		.mx7_timing = false
+	},
+	{
+		.nregs = 128,
+		.banked = false,
+		.regs_per_bank = 0,
+		.mx7_timing = false
+	},
+	{
+		.nregs = 64,
+		.banked = true,
+		.regs_per_bank = 4,
+		.mx7_timing = true
+	},
 };
 
 static const struct of_device_id imx_ocotp_dt_ids[] = {
-- 
2.7.4